I did a search, but wanted to see if anyone currently on the board had any suggestions with this.

98 Chevy Blazer LT w/ 4whl Drive
Approx 120k miles

Last "tune up" (wires/plugs/cap/rotor) was less than a year ago.
Last fuel filter replacement was less then 4k miles ago

Ran a injector cleaner a week ago...with some, yet little improvement.
Vehicle still seems sluggish.

I had a feeling it was more of a sensor issue...something with MAS or MAP, but I have no warning lights, and the computer shows no error codes. I dont want to replace either for $100 + and find out its neither.

Any common issues that people have found and fixed?

Noone at all has any advice here?

Well I will get you started.
What engine?
What kind of spark plugs? Air filter? Any missing?
How is that fuel pressure?
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

Pull plugs and have a look at them.
And double check that fuel filter.
Check for good hot blue spark to aall plugs.
Also if good fuel pressure and good ignition.
You may need to check that back pressure on the exhust system.
MT

I do have trouble cold starting. Usually takes the second time around.
I dont want to sound too stupid, but once I get a fuel pressure gauge, how do I connect it to check?
thanks
J

Is it constant or intermittent? You mentioned all the basics that you replaced, but wires have been known to fail. If you say intermittent, are the outside conditions damp, or cold and the problem presents itself (staggering) after a few minutes of driving. Do you have problems after rain or a carwash?

intermittant......and I havent found any consistent conditions that contribute to or lessen the effect.

MAF sensor needs cleaning.

MAF is clean

I do have trouble cold starting. Usually takes the second time around.
I dont want to sound too stupid, but once I get a fuel pressure gauge, how do I connect it to check?
thanks
J

There is a test port/adpter on your fuel rail.
A good type fuel pressure gauge will have the fittings to hook it up.
Even if no cold start problems you need to run a the full fuel pressure test.
It is the only way to seperated from a fuel problem or other.
Tape the fuel gauge to windshield or mirrow and have it on there when it does it.
MT

Regardless of personal feelings and past behavior, personal attacks can not and will not be tolerated. I have removed all the inappropriate material from this thread. If this continues, I'll be forced to lock this thread.

I would still point the finger at a malfunctioning MAF sensor.

Most hesitation on tuned up engines is caused by it.

if both sides of the connection are clean, what more can you do other than replace it? I was trying to get a more definate answer before I dropped $100+ and realized it was still happening

if both sides of the connection are clean, what more can you do other than replace it? I was trying to get a more definate answer before I dropped $100+ and realized it was still happening

A lot of times a good cleaning can help a MAF sensor.
Get some good quick dry electrical cleaner or the special MAT sensor cleaner and just spary the sensor wires inside it good. Do it at least twice spray and let dry and spray it again. No scrubbing or rubbing. Carb cleaner is it next best cleaner.
If you are running a K & N air filter go easy on the oil in it. The oil from them will get in MAF and air tempt sensors and throw them off. Or even road dust from a regular air filter will get dirt in a MAF sensor.
Clean it and see if it helps. Check fuel filter and fuel pressure to post back readings.
How is the spark plugs? How old and what kind? AC-delco?
MT

thanks MT.
Will spray it anyway just as an attempt. I would think it wouldve set off a check engine light if there was a problem with it though. will check the plugs also. replaced them not even a year ago with properly gapped AC Delco plugs.

Josh, You mentioned you did an injector flush, but was this a fuel additive or did you have a professional flush done?

In the past, my mechanic has always done the fuel flush with the single can (IV setup) to the Shrader valve, got the truck running on the cleaner and then pulled the fuel pump relay to run the truck simply on the cleaner. His shop recently switched over to a 3 bottle system. Two bottles hang on the IV rack, one to the Shrader, one hose into the throttle body and a can in the tank afterwards. It does a full cleaning and takes about 30 minutes for the truck to go through the can. The throttle body attachment is like a small injector that sprays into the barrel as the truck idles. My throttle body and butterfly valve had quite a bit of carbon. After the cleaning, a nice bright aluminum/gold colour. Just a thought. I never realized how sluggish my truck felt until after having the system cleaned in this manner. Throttle response is like night and day.

thanks MT.
Will spray it anyway just as an attempt. I would think it wouldve set off a check engine light if there was a problem with it though. will check the plugs also. replaced them not even a year ago with properly gapped AC Delco plugs.

You are welcome.
Give it a whirl and let us all know how it goes.
MT

I just hel;ped a guy over the phone with the exact same problem, he tried everything and then popped in a new MAF and everything was fine.

Remember, you can always take the MAF back after if it is not the cause.

where did you have this done Swalt?

and what would the cleaning be called?

where did you have this done Swalt?

and what would the cleaning be called?

I'm in Toronto so you have a little ways to drive for an injector flush. The flush system is the BG Injector Flush.
http://www.bgfox.com/products.html?type=equip

The best cleaner to use for this is brake cleaner. It evaporates and does not leave any residue on the sensor wires. Some carb cleaners have a lubricant in them to help keep things lubricated when you spray it. Electrical cleaner is good too, but I have always used brake cleaner and always had good results. But I agree with doing you fuel pressure check, and pressure leak down test, at least to rule them out.

I had an injector flush done 2 years ago at the Dealership and it cured my hesitation problems.

I am just curious...........would the recommended 50/50 of Seafoam fix this?

swalt, and cloud -

just made an appointment for 11am today for a full flush at the dealership.
they said it includes a full internal flush for the injectors, and fuel lines, plus a cleaning of the throttle body and a fuel tank additive when theyre done. $129
Not exactly "cheap"....but it'll only take 45minutes total, so I can just go on my lunch break and get it done. I cleaned the MAF the other day with minimal improvment, so I'll post results on this after lunch.

How did it turn out?

those of you that know me, know I did a post about this a while ago.
I checked plugs, all of which looked fine. Nothing out of the ordinary. I changed the fuel filter (way ahead of its needed time), and had a fuel system cleaning done by the dealer to clean the lines and injectors.
Unfortunately, the surging and hesitation still exists. I found out today for a fact that wetness makes it MUCH worse. At slow speeds (i.e. - 1st gear) it sounds like its starving for fuel, and my other symptom is a longer starting time when the car has sat for a while.

I'm going to check the fuel pressure, as I assume this has to be the problem...I might bring it somewhere to have it checked...but I wondered if anyone had any suggestions, given the info just provided about rainy days making the problem MUCH worse.

Sound like a vacuum leak somewhere? Anyone had similar problem with fuel?

PLUG WIRES!!!! Or cap and rotor! I'd put money on it! Check tonight in the dark - take a spray bottle with water in it and mist your wires while the engine is running. I bet you'll see them arcing. I had this problem with cheap wires but even age and wear can cause it. Moisture usually only affects electrical issues and not fuel pressure. I think you can spray the wires with WD-40 or silicone spray to dry them off to get you to the store if need be.

PLUG WIRES!!!! Or cap and rotor! I'd put money on it! Check tonight in the dark - take a spray bottle with water in it and mist your wires while the engine is running. I bet you'll see them arcing. I had this problem with cheap wires but even age and wear can cause it. Moisture usually only affects electrical issues and not fuel pressure. I think you can spray the wires with WD-40 or silicone spray to dry them off to get you to the store if need be.

I agree. That was the first thing that I thought of, too.

I changed them about a year ago. Plugs, Wires, Cap and Rotor. They're Bosche wires. Seems unlikely that they'd be the cause this soon.
Im still thinking its a fuel issue. Never felt a car surge the way this does in only low gear and had it be an electrical problem. Especially with the everpresent starting delay. Seems to me like its not getting enough gas at low speeds and when you step on it, its enough pressure once you get up to speed to keep pressure built up.
But I can try what you're saying. Thanks for the the suggestion.

If it is your wires... You're feeling less problem at higher speed because the truck is actually working less than when you're accelerating to speed. I've had bad wires out of the box. Besides remember K.I.S.S!

K.i.s.s. ????

K.i.s.s. ????
A famous band:
http://www.kissonline.com/news/images/1_kjpn.jpg












j/k
It means "Keep It Simple Stupid" or "Keep It Super Simple"

yea yea. I got it. if I had to guess I'd say its 10 to 1 a fuel issue. but I'll go out in a few and spray the wires and report back

ok did it.
I DID in fact seem some slight arcing.
One where a wire ran against a cooling hose, and the most obvious being the COIL wire...both on the wire, and at the engine connection.
I felt slight hesitation when I drove it like that, although I would think it would have been much more extreme given how bad it was today, and how much more I just soaked them looking for the ARC.

MUZZY and BLAZEE:
You said you had the problem before...have either of you had this issue, and the symptom was what I'm having? A surging on acceleration that feels like the car is almost studdering? Also, is there any chance that it'd be caused by some sort of vacuum leak?

ok did it.
I DID in fact seem some slight arcing.
One where a wire ran against a cooling hose, and the most obvious being the COIL wire...both on the wire, and at the engine connection.
I felt slight hesitation when I drove it like that, although I would think it would have been much more extreme given how bad it was today, and how much more I just soaked them looking for the ARC.

MUZZY and BLAZEE:
You said you had the problem before...have either of you had this issue, and the symptom was what I'm having? A surging on acceleration that feels like the car is almost studdering? Also, is there any chance that it'd be caused by some sort of vacuum leak?

I had your exact symptoms that's why I was so sure it was the wires. Studdering is exactly what's happening. You're tyying to accelerate the truck is trying to accelerate by firing the plugs faster but the arcing is grounding the plug or plugs out so you're truck is studdering. Could there be other issues? Of course it's a Blazer - like the weather, if nothing is wrong wait 15 minutes. You saw arcing so there is your KISS problem. Replace the wires then see how she runs.

will do, they're bosches, so I think I have a warranty anyway

Just replaced the wires, I'll report back if the problem disappears or reappears.

I put a post up here a couple days ago with a similar problem. Thought it was the cap when in fact it was the cap housing cracked where it screws in. My problem would only happen after a few minutes of driving on a cool morning, assuming condensation was building up inside the cap as the engine warmed up.

thanks Swalt, I'll keep my eye on the cap and rotor next if the problem persists....its fairly moist this morning, and will rain in my area this afternoon. its a good test day.

ok...heres the current situation.....

replaced the wires, and although it hasnt surged since, I'm not completely sure it fixed the problem...

BUT..I now have an additional problem since changing the wires. My gas mileage is HORRIBLE. Running through a tank in almost a day of regular driving. All I can think of is that I damaged a plug, or the cap and rotor during the wire change. Im not really noticing a rough idle, but...

Anyone have any other suggestions? Should I have reset the computer after changing the wires? HELP!

ok...heres the current situation.....

was having an arcing issue with 1yr old Bosch wires.
replaced the wires, and although it hasnt surged since, I'm not completely sure it fixed the problem...

BUT..I now have an additional problem since changing the wires. My gas mileage is HORRIBLE. Running through a tank in almost a day of regular driving. All I can think of is that I damaged a plug, or the cap and rotor during the wire change. Im not really noticing a rough idle, but...

Anyone have any other suggestions? Should I have reset the computer after changing the wires? HELP!

also I plan on replacing the fuel filter tonight...although I seriously doubt it caused this sudden drop in gas mileage. Would lean more towards whatever is causing it the hard start when its been sitting

JOSH, Just alot of Two Cent's here????

What year is it? 4wd or 2wd?
What Brand of Sparkplugs are you running in it right now? How old?
When was the last time you changed the cap and rotor?
Air filter is how old?
PCV Valve is how old?
Sticky Brakes possible?
Dirty injectors?
You mentioned Fuel filter already.
I belive that the gasoline we are using is still the winter blend (SHITTY)
Tire pressure OK?
Does your Fan blade spin freely?
Transmission fluid clean and full?

JOSH, Just alot of Two Cent's here????

What year is it? 4wd or 2wd?
What Brand of Sparkplugs are you running in it right now? How old?
When was the last time you changed the cap and rotor?
Air filter is how old?
PCV Valve is how old?
Sticky Brakes possible?
Dirty injectors?
You mentioned Fuel filter already.
I belive that the gasoline we are using is still the winter blend (SHITTY)
Tire pressure OK?
Does your Fan blade spin freely?
Transmission fluid clean and full?

1998 Chevy Blazer LT (4wd)
AC Delco's replaced last March 05 (basically a year old)
Changed wires/cap and rotor at that same time
Air Filter in Feb. of 05 (K&N was checked and is still clean)
PCV Valve was changed in March 05
Brakes seem fine
Just had a full fuel system cleaning done by dealer.
(yes fuel filter is fairly new but will change it anyway tonight)
Tire Pressure fine, no recent changes in it
Fan blade spins freely
Trans. Fluid is clean, but I do have a slow tranny leak at the radiator.
(I have added some occasionally so I beleive its full...why do you ask?)

Clean the MAFS in the air intake. See if that helps. Front O2 sensor could cause this but shiould see a SES light and have a code.

Clean the MAFS in the air intake. See if that helps. Front O2 sensor could cause this but shiould see a SES light and have a code.


hey muddog...thanks. I did this less than a week ago trying to solve the hesitation problem....but saw no change. The gas mileage issue just started.

What is the one electrical CONNECTOR that runs into the distributer cap?

I know this is blurry...but...

although it was changed out less than a year ago, I just pulled the PCV to check it out as well. rattles freely-allowing flow one way only...which I know is the main function....but it shows signs of what looks like burnt fuel (brownish buildup). Just wanted to ask if thats normal or a sign of any other issue?

http://i16.photobucket.com/albums/b40/JoshB_/pcv.jpg

A couple more questions to help us help you if you don't mind.

what was the mpg before ? and for how long?
what is the current mpg ? and for how long?

A couple more questions to help us help you if you don't mind.

what was the mpg before ? and for how long?
what is the current mpg ? and for how long?

I dont know to be honest. It was pretty much average for most Blazer owners before...and its dropped a HUGE amount all of a sudden.

anytime u change wires for a misfire your gonna wanna chane the plugs too because the longer they r not being fired the more fouled they r getting. Im sure some are fouled out pretty badly by now and they wont clear up with everyday driving.

Are you driving with the A/C going or the front defroster or blend on. Using that with the air temp being above 40 degrees F will cause the air conditioning compressor to kick on.

AC compressor on=more load=more gas to do same amount of driving

Check under the hood anyway, there might be a sticky switch or relay that's keeping the compressor going.

Also where you getting your gas? Have you changed brands lately? Some stations are now using a blend of gasoline and ethanol. Dont know if that will help or hurt mileage, mine doesnt like the 10% ethanol blend.

anytime u change wires for a misfire your gonna wanna chane the plugs too because the longer they r not being fired the more fouled they r getting. Im sure some are fouled out pretty badly by now and they wont clear up with everyday driving.

does anyone agree with this?

Is your poor mileage over just one tank of gas? Because it is possible you could have gotten a poor batch from that Gas Station. Try a different one like Sunoco, Shell, Exon. Those are usually the higher quality stations at least in my area. The local SuperAmerica is causing horendous mileage on several family members cars. They are averages 50MPG lower.

They should be changing over to summer grade here shortly, but we have to wait for the Winter Grade to dry up first.

also I plan on replacing the fuel filter tonight...although I seriously doubt it caused this sudden drop in gas mileage. Would lean more towards whatever is causing it the hard start when its been sitting

If you are having a hard start cold.
Here is one thing to check but the fuel pressure specs will depend on year and engine and engine code. Which you have not gave us. Post them back.
MT

Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

somewhat agree.

I would do the cap, rotor, wires and plugs all at the same time if they were being changed because they were very old and had high miles.

If not then I would disagree and only change the bad component.

My symptoms are a bit like yours, but very intermittent and light. It seems to be worse when it is wet , cold, or when all the lights, fans are on.

I can't remember where, but vagualy remember something about unhookling alternator and testing injectors with lower voltage.. I wish I could remember, because My problem is nearly non-existant with no lights on.

they werent being changed due to old age. they're about one year old. which is pretty new in my opinion. I changed them out because I saw the ARCing.

Unfortunately, the surge problem pursists. Any suggestions let me know.
Im starting to really lean towards believing its a fuel pump or pressure leak as I said before. Hard start after it sits persists as well.

Josh,

Where exactly was the arcing?

Josh,

Where exactly was the arcing?


Hey Muzzy -

Re-read post #9

How did it turn out?


This DID NOT solve the problem......search continues

thanks MT.
Will spray it anyway just as an attempt. I would think it wouldve set off a check engine light if there was a problem with it though. will check the plugs also. replaced them not even a year ago with properly gapped AC Delco plugs.

HOW IS THAT FUEL PRESSURE?
Do not leave home without it.
MT

Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

HOW IS THAT FUEL PRESSURE?
Do not leave home without it.
MT

Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

Can you explain the "pinch" off part? How to, where it is, etc?

Find the rubber hose on the return line around fuel filter and check pressure with it pinched off.
Also you can get a direct full fuel pressure test at the line going into fuel filter.
Just do not run fuel pump at full pressure over 30 seconds.
Post back fuel pressures.
MT

Find the rubber hose on the return line around fuel filter and check pressure with it pinched off.
Also you can get a direct full fuel pressure test at the line going into fuel filter.
Just do not run fuel pump at full pressure over 30 seconds.
Post back fuel pressures.
MT

"return line" ????

is the place before the fuel filter a fitting? or do you have to remove the line from the filter? if its just a fitting like the one on the fuel rail, I'd think it would be smart to check BEFORE and AFTER the fuel filter.

Define "full pressure" for the fuel pump? Key on? Or vehicle running?
And if its full pressure with the vehicle running, how in the hell do you get readings WHILE driving like Ive seen so many people suggest?

ALSO - the only tester I can find is at a local AUTOZONE, and they claim it covers all GM vehicles up to 95 or 96. Did it change after that? Or can I use this one on my 98?
If not, anyones suggestions on WHERE TO GET ONE, PRICE, and part number would be greatly appreciated

Return line is the fuel return line from engine back to the fuel tank.
You can plug it off or pinch the rubber hose that it has on it fuel filter to engine lines.
Full fuel pressure is all that the pump will put out with return line close/shut/pinched off. oryou can check full pressure at the fuel line going into fuel filter. Hook a gauge right on the end of it.
Running on the road fuel pressure you need to tape the fuel gauge to the windshield or mirrow and drive down the road 15-20 minutes and watch fuel pressure.
Why did they not check your fuel pressure and check the injectors when they done the injector clean? Or were they in to big of a hurry to get your money with a 30 minutes injector clean job?
Get that fuel pressure gauge on there and tell us what the readings are.
MT
MT.

"return line" ????

is the place before the fuel filter a fitting? or do you have to remove the line from the filter? if its just a fitting like the one on the fuel rail, I'd think it would be smart to check BEFORE and AFTER the fuel filter.

Define "full pressure" for the fuel pump? Key on? Or vehicle running?
And if its full pressure with the vehicle running, how in the hell do you get readings WHILE driving like Ive seen so many people suggest?

ALSO - the only tester I can find is at a local AUTOZONE, and they claim it covers all GM vehicles up to 95 or 96. Did it change after that? Or can I use this one on my 98?
If not, anyones suggestions on WHERE TO GET ONE, PRICE, and part number would be greatly appreciated


You check full pressure with engine off and fuel pump running what ever way you can get it to run. You can jumper the fuel pump prime connecter with a fused jumper or keep fliping the key on with engine off to prime it up to full presure.
Full pressure is checked with return line blocked.
Normal/regular pressure just put the gauge on it.
All 90 and 20 gm engines use the same sise fuel pressure test port on the ones that have a test port.
MT

I'm telling you Josh, go get a new MAF and try it out.

If it doesn't work you can send it back.

May really help you trouble shoot.

Sometimes a cleaning won't help a defective sensor and MAf's aren't that expensive when compared to the cost of the cleaning and treatments and throwing parts at your truck.

The results:

Key Off - 0psi

Key On (engine off/fuel pump prime) - Jumped to 60psi, and then dropped quickly to 0psi

Engine Running - 54psi

WHAT THE HELL!!!!!!!!????????
Is there a check valve? Or is this the fuel pressure regulator!??!?!? Can someone explain exactly WHERE the regulator is as well so I can make sure a vac. line didnt come unplugged etc.

Looks like you have a leak in the system. The most probable causes would be the regulator (in the intake) or the pulsator (in the tank). Does the pressure drop to 0 with the return pinched? A good way to figure out which end the problem is on is to test the pressure at the filter.

Looks like you have a leak in the system. The most probably causes would be the regulator or the pulsator. Does the pressure drop to 0 with the return pinched?

I didnt try this yet....do I do it WHILE its running? Because it doesnt keep pressure in the line with the key OFF or ON for more then 2 seconds!

Wheres the regulator and pulsator?

I edited my post while you were replying again. :)

Pinch it off and then turn the key on. Use a pair of vice grips or get someone to turn the key while you hold it. If the pressure stays then it's most likely the regulator.

I edited my post on you again. :)

Pinch it off and then turn the key on. Use a pair of vice grips or get someone to turn the key while you hold it. If the pressure stays then it's most likely the regulator.


if you pinch it off before turning the key, the fuel pressure will never rise correct? maybe you mean turn the key on and THEN pinch it and watch it?

You pinch the return line not the supply line. After the fuel leaves your tank, it goes to the intake and through the fuel pressure regulator, any extra fuel that you don't need is then sent through the return line and back to the tank. If the regulator is bad it will send too much back to the tank and cause the pressure to drop. Pinching the return line blocks the flow of fuel back to the tank and allows you to see how much pressure your pump can supply. In your case it will let us see if the regulator is sending too much fuel back to the tank and causing your pressure to drop to 0.

You pinch the return line not the supply line. After the fuel leaves your tank, it goes to the intake and through the fuel pressure regulator, any extra fuel that you don't need is then sent through the return line and back to the tank. If the regulator is bad it will send too much back to the tank and cause the pressure to drop. Pinching the return line blocks the flow of fuel back to the tank and allows you to see how much pressure your pump can supply. In your case it will let us see if the regulator is sending too much fuel back to the tank and causing your pressure to drop to 0.

I just did what I think you described.
Got underneath, and pinched the fuel return (the only rubber line I saw which was to the rear of the fuel filter.
Again, with the key off, 0psi.
With the key on, UP TO 60psi for a brief second, then drops immediately down to 0psi.
With the engine running it jumps up to approx 54psi, and as soon as the vehicle shuts off, returns to 0psi.

No difference

I'd suggest checking the pressure at the filter itself, if there's no difference there then the problem is most likely the pulsator.

I'd suggest checking the pressure at the filter itself, if there's no difference there then the problem is most likely the pulsator.


do you have AIM? would be much better to talk to you realtime.
thanks
Josh

AIM=rudemoodz

Is the only way to determine if its IN the tank hooking the gauge into the fuel filter? Id like to be positive that its not something simple UNDER THE HOOD, before I take the time to drop the tank. How difficult of a job is it to drop the tank to replace this pulsator? can it be done WITHOUT dropping the tank? How much are all the parts?
Fuel Pump?
Pulsator?
Fuel Sending Unit?

thanks
Josh

To seperate a injector/fuel pressure regulater problem from a weak/bad fuel pump.
You need to hook a fuel pressure gauge direct to the fuel pressure line out of tank.
You will need some more fittings/adapters to do that.
If the parts store did not give them to you with the fuel pressure gauge go back and tell them you need the fittings to hook straight to the fuel pressure line at fuel filter.
The fuel line that goes into the fuel filter is best place to check it.
Remove it from fuel filter and hook right onto the end of it.
If the fuel pump is good you will see 75-85 lbs of full pressure there and a very slow leak down..
If not your fuel pump is weak.
You need at least 75 lbs full pressure to keep a running pressure 65 lbs to the injector unit.
Also check for good voltage and ground at the fuel pump wiring plug in.
If the fuel pump is weak you will need the complete fuel pump module.
Going to cost you. 250-500 $ US
If it has good full pressure of 75-85 lbs of pressure there .
The next place to check for loss of pressure is the fuel pressure regulater in the intake.
MT

do you have AIM? would be much better to talk to you realtime.
thanks
Josh



Sorry I didn't see this sooner. I don't have AIM anymore, but I guess I could set up another account if need be. Looks like MT-2500 has you on the right track now though.

does anyone have a photo of the fitting I need to check pressure at the filter?
My local parts store are idiots.....and they never have any info more than I already know.

I'm leaning towards the fact that its the valve/pump as opposed to the regulator unfortunately. I havent found a fitting yet, but it seems pretty conclusive that if you cut off the return line to the tank and it still leaks just as fast, then its coming from the pump.
Dealer wants $500 for the pump assembly. That includes sending unit, and the pulsator etc.
I can get a Bosch fuel pump (lifetime warranty) from AutoZone for $346.99 that also inclues the sending unit and pulsator. What does everyone reccommend?

If you have horrible gas mileage.....and horrible fuel pressure either due to the fuel pressure valve, pump, or regulator.........can someone tell me how each would affect the gas mileage?

If the Fuel pressure regulator is leaking badly, the pump will not be able to build pressure.
FPR Dumping lotsa gas into the intake= bad mileage.

If the Fuel pressure regulator is leaking badly, the pump will not be able to build pressure.
FPR Dumping lotsa gas into the intake= bad mileage.


that part seems obvious enough...but what about if the valve on the fuel pump is leaking? would that kill gas mileage too? if so, why?

Not sure which valve on the fuel pump you mean. There is a check valve to help keep the supply line charged or full of fuel, if that check valve is bad you will have longer, harder starts, extra cranking as the line is refilled. It will not cause bad mileage.

You also need to stick to one thread for your problem.

If you have horrible gas mileage.....and horrible fuel pressure either due to the fuel pressure valve, pump, or regulator.........can someone tell me how each would affect the gas mileage?

STAY WITH THE POST YOU ALREADY HAVE RUNNING ON IT.
When you find out what is causing the low fuel pressure fix that and your fuel mileage should return.
MT

STAY WITH THE POST YOU ALREADY HAVE RUNNING ON IT.
When you find out what is causing the low fuel pressure fix that and your fuel mileage should return.
MT


i know, my appologie, its just that i dont really always hear back if its not a specific title on the post.
Noone answered my question about if the only way i can check the regulator is to put the tester in line with the filter.
Ive already cut off the return line as intstructed and fuel pressure still dropped. SO -
I cant find the right fittings to put the tester in line (in place of the filter)
Can I check the regulator some other way so I know before I replace the PUMP?

i know, my appologie, its just that i dont really always hear back if its not a specific title on the post.
Noone answered my question about if the only way i can check the regulator is to put the tester in line with the filter.
Ive already cut off the return line as intstructed and fuel pressure still dropped. SO -
I cant find the right fittings to put the tester in line (in place of the filter)
Can I check the regulator some other way so I know before I replace the PUMP?

First things first.
If fuel pressure is bad it may/or will mess up gas mileage.
You need to check and test the fuel pump first. Get it up to full pressure and working good. Then recheck the fuel pressure regulator.
After you get the fuel pump pressure up to par.
The fittings for testing fuel pressure at the fuel filter or fuel line from fuel pump come with the high dollar fuel pressure gauges but for a one time check and to save you from buying them. 50-100$
If you do not have and can not get the fittings to check the pump at fuel filter take it to a repair shop that does and ask them to run the direct fuel pump pressure test for you.
Just make sure you tell them uou want the direct/full pump pressure and not just the pressure at fuel rail which you already have.
After getting good fuel pump pressure.
If the fuel pressure regulator does not control fuel pressure to specs and or has a fast leak down then work on that end.
MT

would a fuel pressure regulator cause a hard start, even though pressure still drops with return line clamped off?

Forget the fuel pressure regulater untill you.
Find out what is causing low fuel pressure like we posted.
First things first.
Check that fuel pump first.
It all Depends on what is causing low fuel pressure.
If it does not have the right fuel pressure you will get a no start or hard start.
MT

Forget the fuel pressure regulater untill you.
Find out what is causing low fuel pressure like we posted.
First things first.
Check that fuel pump first.
It all Depends on what is causing low fuel pressure.
If it does not have the right fuel pressure you will get a no start or hard start.
MT


I know, but would the regulator cause a hard start if it was leaking?
Yes or No?

I know, but would the regulator cause a hard start if it was leaking?
Yes or No?

You got it. The answer is YES and No. It all depends. :grinyes: :lol:
First things first.
FIX THAT FUEL PRESSURE FIRST THING.
Then worry about the fuel regulator.
MT

You got it. The answer is YES and No. It all depends. :grinyes: :lol:
First things first.
FIX THAT FUEL PRESSURE FIRST THING.
Then worry about the fuel regulator.
MT

I know, Im not being a dick. I dropped it at a shop, the mechanic is doing me a favor, and seems convinced that its the regulator. Although, I dont know if he checked the fuel pressure at the filter.

So, if he's going to go ahead and do that, I wanted to ask if that could possibly be the cause of the whole problem, or am I going to have to do both?

I know the regulator drops excess fuel into the intake, and it burns off...which obviously would kill gas mileage. I wanted to know if it could cause a hard start also...therefore POSSIBLY being the cause of both problems..........OR was I still lookin at replacing the fuel pump to fix the cold start alone anyway.

thanks
J

I know, Im not being a dick. I dropped it at a shop, the mechanic is doing me a favor, and seems convinced that its the regulator. Although, I dont know if he checked the fuel pressure at the filter.

So, if he's going to go ahead and do that, I wanted to ask if that could possibly be the cause of the whole problem, or am I going to have to do both?

I know the regulator drops excess fuel into the intake, and it burns off...which obviously would kill gas mileage. I wanted to know if it could cause a hard start also...therefore POSSIBLY being the cause of both problems..........OR was I still lookin at replacing the fuel pump to fix the cold start alone anyway.

thanks
J

First step would be check fuel pressure at fuel filter.
But it is your time and money
Good luck and the answer is.
Same answer yes and know.
Fix the fuel pressure problem. If you do not have fuel pressure it will not run right.
MT

First step would be check fuel pressure at fuel filter.
But it is your time and money
Good luck and the answer is.
Same answer yes and know.
Fix the fuel pressure problem. If you do not have fuel pressure it will not run right.
MT

wow,
are you listening to me?

I KNOW THAT YOU'RE RECCOMMENDING CHECKING PRESSURE AT THE FILTER...WE'VE ESTABLISHED THAT.

But its at a shop right now, and the mechanic is doing me a favor...i.e. - giving me his discount on dealer manufactured parts, and fixing it for next to nothing. I'm not going to call and tell HIM how to do his job.

He believes its the regulator....

Which is WHY right now, I'm asking others on this board that have knowledge of the function of the regulator....if it can cause the hard start also....I know it would cause the bad gas mileage.

I know it doesnt run right without pressure. Which is why its being fixed to begin with.

I didnt want a "YES AND NO" answer telling me again for the tenth time to "CHECK PRESSURE AT THE FILTER".

Just a:

YES a bad REGULATOR CAN CAUSE A HARD START

or

NO a bad REGULATOR WOULDNT CAUSE A HARD START.

Is that so difficult?

wow,
are you listening to me?

I KNOW THAT YOU'RE RECCOMMENDING CHECKING PRESSURE AT THE FILTER...WE'VE ESTABLISHED THAT.

But its at a shop right now, and the mechanic is doing me a favor...i.e. - giving me his discount on dealer manufactured parts, and fixing it for next to nothing. I'm not going to call and tell HIM how to do his job.

He believes its the regulator....

Which is WHY right now, I'm asking others on this board that have knowledge of the function of the regulator....if it can cause the hard start also....I know it would cause the bad gas mileage.

I know it doesnt run right without pressure. Which is why its being fixed to begin with.

I didnt want a "YES AND NO" answer telling me again for the tenth time to "CHECK PRESSURE AT THE FILTER".

Just a:

YES a bad REGULATOR CAN CAUSE A HARD START

or

NO a bad REGULATOR WOULDNT CAUSE A HARD START.

Is that so difficult?

The answer is still Yes and No.
But Last time I am going answer it. :grinyes: :lol:

I have been listening to and reading about this for over a 100 post that has been made on it but.
It really apears you are the one not listening. :grinyes:
You have had some good help and answers on the problem.
More than Several people have tryed to help and gave you some good info.
But you keep evading the issue and do not listen to what they are trying to tell you. And have not answered all of there questions since post 3 on this thing.
It looks to me like it is getting over your head. No offense intended just a professional obersation.
I think it is time for you to get some professional help with it as you said it is in the shop right now.
Let us know how it goes.
Good Luck MT

Possibly an explanation of what the regulator does and how the system operates will help, I find that explaining well the system will allow nearly anyone to diagnose by them selves far easier,,,

A bad regulator CAN cause a hard start, but in this case it may not be the trouble,,,

Possibly an explanation of what the regulator does and how the system operates will help, I find that explaining well the system will allow nearly anyone to diagnose by them selves far easier,,,

A bad regulator CAN cause a hard start, but in this case it may not be the trouble,,,


thank you 534BC. I appreciate answering the actual question that was asked. some people like to be difficult

I think rather than being difficult it may be a matter of misunderstanding. I would explain the system to you, but am not sure I completely understand it. Like I see no difference in testing fuel pressure anywhere inbetween the pump and where it goes to the engine.

I think rather than being difficult it may be a matter of misunderstanding. I would explain the system to you, but am not sure I completely understand it. Like I see no difference in testing fuel pressure anywhere inbetween the pump and where it goes to the engine.

Well.
All you have to do is go back and read the 99 or more post that was made on it.
It was all explained several times. like look at post 78.
Several people have answered the post and have tryed to help and have gave some good info on it.
But some how Josh Barber evades the questions and wanders off onto something else. If he can not take the advise he has been given and the answers and does not answer his post with the questions that were asked him.
We can not help him. It is time for him to hang it up and get professional help which he has posted he has done.
And it would be consederate of him to post back what he finds or how he comes out on it.
MT

Well.
All you have to do is go back and read the 99 or more post that was made on it.
It was all explained several times. like look at post 78.
Several people have answered the post and have tryed to help and have gave some good info on it.
But some how Josh Barber evades the questions and wanders off onto something else. If he can not take the advise he has been given and the answers and does not answer his post with the questions that were asked him.
We can not help him. It is time for him to hang it up and get professional help which he has posted he has done.
And it would be consederate of him to post back what he finds or how he comes out on it.
MT

I'm not going to argue with you online..its a little pointless.
You can think I'm "over my head" and I'll believe you're intentionally being difficult. I'm a engineering technician for the Dept. of Defense and my job is to build/troubleshoot Mk48 Torpedos. But you go ahead and continue to attempt to be condescending to me. I think its cute.

I will post back my results for anyone that it may help

The explanation in the post 78 was not a complete explantion. A thorough understanding of the components and way it is plumbed is nessecary to troubleshoot. Otherwise one is left doing things or replaceing parts "because the book says to"

I think most posters here have a understanding of the fuel system, if an explanation of how its plumbed is given and the components then it is easy to diagnose.

Here's a few questions pop into my head.

Is the regulator before the injectors? Is it a 2 port regulator?

What is the oputlet pressure?

The explanation in the post 78 was not a complete explantion. A thorough understanding of the components and way it is plumbed is nessecary to troubleshoot. Otherwise one is left doing things or replaceing parts "because the book says to"

I think most posters here have a understanding of the fuel system, if an explanation of how its plumbed is given and the components then it is easy to diagnose.

Here's a few questions pop into my head.

Is the regulator before the injectors? Is it a 2 port regulator?

What is the oputlet pressure?\


BINGO bro.
These to answers would explain a lot.

Here is the question that was asked.

Is the only way to determine if its IN the tank hooking the gauge into the fuel filter? Id like to be positive that its not something simple UNDER THE HOOD, before I take the time to drop the tank. How difficult of a job is it to drop the tank to replace this pulsator? can it be done WITHOUT dropping the tank? How much are all the parts?
Fuel Pump?
Pulsator?
Fuel Sending Unit?

And here is my answer in post 78

To separate an injector/fuel pressure regulator problem from a weak/bad fuel pump.
You need to hook a fuel pressure gauge direct to the fuel pressure line out of tank.
You will need some more fittings/adapters to do that.
If the parts store did not give them to you with the fuel pressure gauge go back and tell them you need the fittings to hook straight to the fuel pressure line at fuel filter.
The fuel line that goes into the fuel filter is best place to check it.
Remove it from fuel filter and hook right onto the end of it.
If the fuel pump is good you will see 75-85 lbs of full pressure there and a very slow leak down..
If not your fuel pump is weak.
You need at least 75 lbs full pressure to keep a running pressure 65 lbs to the injector unit.
Also check for good voltage and ground at the fuel pump wiring plug in.
If the fuel pump is weak you will need the complete fuel pump module.
Going to cost you. 250-500 $ US
If it has good full pressure of 75-85 lbs of pressure there .
The next place to check for loss of pressure is the fuel pressure regulater in the intake.
MT


Note
To separate an injector/fuel pressure regulator problem from a weak/bad fuel pump.
You need to hook a fuel pressure gauge direct to the fuel pressure line out of tank.
If the fuel pump is good you will see 75-85 lbs of full pressure there and a very slow leak down..
If not your fuel pump is weak.
You need at least 75 lbs full pressure to keep a running pressure 65 lbs to the injector unit.
If it has good full pressure of 75-85 lbs of pressure there .
The next place to check for loss of pressure is the fuel pressure regulater in the intake.

Now that is about as plain as I can answer the question and without determining the fuel pump is up to par or capable of putting out full pressure without a fast leak down there is no point of or any way to check the rest of the fuel system.
As far as to how the fuel pressure regulator works it is a pressure regulator that is on the end of the fuel rail that feeds the injector unit from the fuel pump. It has a return line that goes back to the fuel tank and regulates the fuel pressure at 60/66 lbs of fuel pressure depending on engine vacume inside the intake. It can drop fuel pressure by way of a external leak or fail to hold back the fuel pressure at 60/66 lbs the fuel/injector feed rail.
It is a simple vacume operated diaphragm that holds fuel pressure at 60/66 lbs of pressure.
But for it to work right the fuel pump needs to be capable of pumping/holding at least 67 lbs or more fuel pressure to it all of the time.

That is why the fuel pump needs to be tested and checked first.
If the fuel pump is weak or bad the rest of the system will not work right or can not be tested.
First things first. Check that fuel pump. And post results.
Then I would be happie to help you test the rest of the system.
MT

sounds like it is not a regulator at all and simply a simple relief valve , in either case if it's plumbed in between the pump and the next component then it can indeed cause the problem (of low pressure) I supose this is when to pinch that return line off and keep testing at the test port , right?

sounds like it is not a regulator at all and simply a simple relief valve , in either case if it's plumbed in between the pump and the next component then it can indeed cause the problem (of low pressure) I supose this is when to pinch that return line off and keep testing at the test port , right?

Pinching off the return line is one of the first steps in testing.
Pinching off return lines shuts off all pressure from being returned back from tank.
Then if the fuel pump is putting out good pressure and is not leaking back into the fuel tank. And a supply fuel line is not leaking off.
The injector unit/injector and or the fuel pressure regulator is leaking the pressure off.
On this one the injector body and injectors and fuel pressure regulator are all inside the upper intake.
To check them for leakage you need to pull the upper intake and prime up fuel pressure and watch for leakage.
Bright spots and raw gas in the intake is the thing to watch for.
MT

If it is working right it regulates/holds the fuel pressure from 60 to 66 lbs according to engine vacume.
Full load/no vacume it should go to 66 lbs.
No load /full vacume it drops pressure back to 60 lbs.
It does regulate from 60/66 lbs pressure.
And it dumps all extra pressure back into the fuel tank.
But you could say it works as a relief valve to.
It relievs all extra pressure.
MT

If it is working right it regulates/holds the fuel pressure from 60 to 66 lbs according to engine vacume.
Full load/no vacume it should go to 66 lbs.
No load /full vacume it drops pressure back to 60 lbs.
It does regulate from 60/66 lbs pressure.
And it dumps all extra pressure back into the fuel tank.
But you could say it works as a relief valve to.
It relievs all extra pressure.
MT

After enitial teardown, fuel pressure regulator showed no signs of leak off nor while running. Pressure continued to only be 54psi while running....0psi off. Appears to be the fuel pump, or the checkvalve there-in.

This is what I'd told the mechanic ahead of time. I gave him a paper that I printed up giving him all the pressure readings and information I'd already concluded after pinching the return line..as well as making it clear on the phone that I believed it to be the pump or pump valve, although I needed to pull a pressure test at the filter (thanks to MT-500's suggestion). He said he would do so "not to worry about it", that he'd take care of it, and that he wouldnt be charging me to diagnose it.

After diagnosing it originally:

He told me he was sure it was the regulator. I didnt question if he pulled pressure at the filter, as I'd already been adement about it...and felt I was telling him how to do his job when he was doing me a favor to begin with. I told him thats fine, to remember that I told him otherwise.....
sure enough......NOT THE REGULATOR.
So he appologized for the delay/inconvience, and didnt charge me for the tear down.

Current status:
He's now told me he's sure its the fuel pump, and that he checked pressure at the filter with the same result.

Instead, he ordered a new GM pump assembly for 18gallon tank (pump/level sending unit etc) from the dealer normally $500 (received @ his cost) for $420(part) + $90(labor) to drop the tank and install it. $510 total.

I could've got an AutoZone Bosch pump for $346 and had it installed = $436 approx.

But I've been told by many people that the aftermarket pumps die out quick. I figured for an additional $75 it was worth getting a part that is made specifically for my vehicle, and has a better reputation. I'm tired of purchasing cheaper parts from AutoZone and having them not mate up to my vehicle correctly because they're made to fit 20+ various different vehicles.

I'm hoping the fuel pump is the cause of the horrible MPG and surging as well as the hard start. Hey...if nothing else, Im looking forward to a quietter pump, and a accurate fuel guage for the first time since I've owned it! :)

I will report back.

After enitial teardown, fuel pressure regulator showed no signs of leak off nor while running. Pressure continued to only be 54psi while running....0psi off. Appears to be the fuel pump, or the checkvalve there-in.

This is what I'd told the mechanic ahead of time. I gave him a paper that I printed up giving him all the pressure readings and information I'd already concluded after pinching the return line..as well as making it clear on the phone that I believed it to be the pump or pump valve, although I needed to pull a pressure test at the filter. He said he would do so "not to worry about it" that he wouldnt be charging me to diagnose it.

He told me he was sure it was the regulator, although he hadnt checked pressure at the filter. I told him thats fine, to remember that I told him otherwise.....sure enough......not the regulator.
So he appologized for the delay/inconvience, and didnt charge me for the tear down.

Instead, he ordered a new GM pump assembly (pump/level sending unit etc) from the dealer normally $500 (received @ his cost) for $420(part) + $90(labor) to drop the tank and install it. $510 total.

I could've got an AutoZone Bosch pump for $346 and had it installed = $436 approx. But I've been told by many people that the aftermarket pumps die out quick. I figured for an additional $75 it was worth getting a part that is made specifically for my vehicle, and has a better reputation. I'm tired of purchasing cheaper parts from AutoZone and having them not mate up to my vehicle correctly because they're made to fit 20+ various different vehicles.

Will report back after its installed.

Thanks for letting us know how it is going.
And 10-4 on cheaper parts.
Always better to go dealer OEM or if you do go aftermarket make sure it is OEM quality.
A lot of aftermarket parts co. have parts made up to there own specs.
They may even carry a major brand but are not full OEM quality or specs.
After you get the fuel pump replaced I would recheck the fuel pressure and check for leakdown.
Before you can rule out a bad regulator it needs to be tested under normal fuel pump pressure.
The 55 lbs of pressure may not be enough to make it leak or show up bad or good. The normal fuel pressure of 60-66 lbs will test it.
If no leak down down and 60-66 lbs of fuel pressure after fuel pump replacement it will be in good shape. It should run a lot better.
And gas mileage should go back to normal
Good luck and let us know how it goes.
MT

Thanks for letting us know how it is going.
And 10-4 on cheaper parts.
Always better to go dealer OEM or if you do go aftermarket make sure it is OEM quality.
A lot of aftermarket parts co. have parts made up to there own specs.
They may even carry a major brand but are not full OEM quality or specs.
After you get the fuel pump replaced I would recheck the fuel pressure and check for leakdown.
Before you can rule out a bad regulator it needs to be tested under normal fuel pump pressure.
The 55 lbs of pressure may not be enough to make it leak or show up bad or good. The normal fuel pressure of 60-66 lbs will test it.
If no leak down down and 60-66 lbs of fuel pressure after fuel pump replacement it will be in good shape. It should run a lot better.
And gas mileage should go back to normal
Good luck and let us know how it goes.
MT

I assume if it proves to be the pump alone, that the computer must overcompensate for the lack of pressure, and burn more fuel somehow?

I assume if it proves to be the pump alone, that the computer must overcompensate for the lack of pressure, and burn more fuel somehow?

Yes it will do things like that. The computer does not actually know what the fuel pressure is but low fuel pressure will cause less fuel to go threw the injector and the system to burn lean and when the computer sees it has a lean mixture or engine running lean it will try to rich up the fuel mix with more injector pulse and in turn burn more fuel or lower gas mileage.
On that 4.3 engine the injectors are very sensitive to fuel pressure.
Low fuel pressure can cause a no start cold. A lot of times the injector will not squirt fuel without the 65 lbs of pressure cold.
After you get it started cold it will run and start all day on lower fuel pressure but may not run quite right and may actually burn more gas.
MT

Yes it will do things like that. The computer does not actually know what the fuel pressure is but low fuel pressure will cause less fuel to go threw the injector and the system to burn lean and when the computer sees it has a lean mixture or engine running lean it will try to rich up the fuel mix with more injector pulse and in turn burn more fuel or lower gas mileage.
On that 4.3 engine the injectors are very sensitive to fuel pressure.
Low fuel pressure can cause a no start cold. A lot of times the injector will not squirt fuel without the 65 lbs of pressure cold.
After you get it started cold it will run and start all day on lower fuel pressure but may not run quite right and may actually burn more gas.
MT


I figured that was the case. I'm surprised it always has started on the second try with only the jump to the 60lbs psi when the pump primed, then back to zero as soon as it shut off.

I'm going to pick it up now. He said pressure reads and holds perfect.
As I said...$510....(ugh....but at least it fixes a bunch of issues....poor fuel level readings, noisey pump, shitty mileage, hard cold starts, and the surging/hesitating).

You gotta admit...$90 to drain/drop the tank and install the new one is pretty cheap. I've done it without a lift with my father on his truck, and its a PITA. Just wish the Dealer pump wasnt such a ripoff. Oh well...a least I got it for $420~!

Should I assume my plugs are all gunked up from running rich now? Or no?

I'll give another report back after driving.

GODDAMNIT!

Job was completed, unfortunately I couldnt get home to get my fuel pressure gauge to bring with me when I picked it up. So I just had to take his word.

The car started immediately on the first click. Good

Pump was quiet as a mouse...no loud buzzing. Good

No surging at all on the drive home. Good

Get home, replace the fuel filter, and recheck pressure at the fuel rail.

OK explain this:
Key off = 60psi
Key on = 64psi then drop to 60psi when pump stops priming (and holds)
Engine running = 54psi !!!!!!!!! (it moves up a bit with acceleration, but 54psi @ Idle)

WTF!?!?!?!?!?!?!

Where am I leaking NOW!?!?!?!?!?!? Is the regulator leaking when running? Or is it the fact that I have a lower intake manifold gasket leak? I know I have this gasket leak. Would it have anything to do with it? Its supposed to HOLD 60-64 while running right? Im so pissed. I plan on calling him first thing tomorrow and telling him something is still not right.

HELP!

GODDAMNIT!

Job was completed, unfortunately I couldnt get home to get my fuel pressure gauge to bring with me when I picked it up. So I just had to take his word.

The car started immediately on the first click. Good

Pump was quiet as a mouse...no loud buzzing. Good

No surging at all on the drive home. Good

Get home, replace the fuel filter, and recheck pressure at the fuel rail.

OK explain this:
Key off = 60psi
Key on = 64psi then drop to 60psi when pump stops priming (and holds)
Engine running = 54psi !!!!!!!!! (it moves up a bit with acceleration, but 54psi @ Idle)

WTF!?!?!?!?!?!?!

Where am I leaking NOW!?!?!?!?!?!? Is the regulator leaking when running? Or is it the fact that I have a lower intake manifold gasket leak? I know I have this gasket leak. Would it have anything to do with it? Its supposed to HOLD 60-64 while running right? Im so pissed. I plan on calling him first thing tomorrow and telling him something is still not right.

HELP!

Ouch.
Unless you fuel pressure gauge is off/sticking some.
If you have another blazer handy to try it on it .
It looks like the fuel pressure regulator is not regulating right or bypassing the fuel pressure to much.
It would take a large external leak to drop the pressure while running.
Engine running at idle should be 60-62 range full load or engine cranking should be 65-66 lbs range.
Full engine vacume should be 60 lbs and no vacume /engine under full load or engine cranking should be 65-66 lbs.
If the regulator was leaking external you would see a fast leak down on fuel pressure with engine off.
When you take it back to the shop take your fuel pressure gauge with it and check it with his pressure gauge.
It is very easy for a fuel pressure gauge to be off or out of calberation.
The lower intake/coolant leak should not affect the fuel pressure.
Let us know how it goes.
MT

Ouch.
Unless you fuel pressure gauge is off/sticking some.
If you have another blazer handy to try it on it .
It looks like the fuel pressure regulator is not regulating right or bypassing the fuel pressure to much.
It would take a large external leak to drop the pressure while running.
Engine running at idle should be 60-62 range full load or engine cranking should be 65-66 lbs range.
Full engine vacume should be 60 lbs and no vacume /engine under full load or engine cranking should be 65-66 lbs.
If the regulator was leaking external you would see a fast leak down on fuel pressure with engine off.
When you take it back to the shop take your fuel pressure gauge with it and check it with his pressure gauge.
It is very easy for a fuel pressure gauge to be off or out of calberation.
The lower intake/coolant leak should not affect the fuel pressure.
Let us know how it goes.
MT


Compare the Before and After (Im thinking maybe he only checked the regulator with the key on...which meant it only had a bit of pressure when the pump primed, and then dropped to 0psi as soon as it stopped...which might have not shown a leak) Does this sound like the regulator.

BEFORE-------------------------------------AFTER

KEY OFF : 0psi--------------------------------------55-60psi

KEY ON: 60psi prime - immed. drop to 0psi------------60psi prime - immed drop/hole @ 54psi

ENGINE @ IDLE : 54psi-------------------------------54psi


Sound like the regulator is opening to quickly?
The new pump basically just solved the problem with the line not holding ANY pressure. With the old pump it ran at 54psi but didnt hold when engine was off. Now it runs at 54psi, and holds in the line when shutoff.

Compare the Before and After (Im thinking maybe he only checked the regulator with the key on...which meant it only had a bit of pressure when the pump primed, and then dropped to 0psi as soon as it stopped...which might have not shown a leak) Does this sound like the regulator.

BEFORE-------------------------------------AFTER

KEY OFF : 0psi--------------------------------------55-60psi

KEY ON: 60psi prime - immed. drop to 0psi------------60psi prime - immed drop/hole @ 54psi

ENGINE @ IDLE : 54psi-------------------------------54psi


Sound like the regulator is opening to quickly?
The new pump basically just solved the problem with the line not holding ANY pressure. With the old pump it ran at 54psi but didnt hold when engine was off. Now it runs at 54psi, and holds in the line when shutoff.

That is what the pressure reading indicate.
But to be sure that the fuel pump is good even if it is new pinch off the return line and see if the fuel pressure jumps up to around 75-85 lbs of pressure or more.
But do not hold/run it at full pressure on it for over 30 seconds.
If the fuel pump is not putting out good full pressure check things like voltage to it and grounds.
If it is good and capable of putting out the full pressure of 75-85 lbs then it points to the fuel pressure regulator not holding the correct pressure.
Let us know how it goes.
MT

That is what the pressure reading indicate.
But to be sure that the fuel pump is good even if it is new pinch off the return line and see if the fuel pressure jumps up to around 75-85 lbs of pressure or more.
But do not hold/run it at full pressure on it for over 30 seconds.
If the fuel pump is not putting out good full pressure check things like voltage to it and grounds.
If it is good and capable of putting out the full pressure of 75-85 lbs then it points to the fuel pressure regulator not holding the correct pressure.
Let us know how it goes.
MT


I just spoke to him and asked him a few questions. He said you cant run the vehicle with the cover off to watch the regulator for leaks...not sure if thats true or not. But that means he only took the cover off to view the regulator for clean spots, and to look for a leak with the key on.

As I said before, when he looked at it, it only held pressure when the fuel pump primed, then dropped IMMEDIATELY when the pump stopped. So perhaps there wasnt any sign of obvious leakage when there was so little pressure from the pump leak, like you'd mentioned....although, I asked if there were any clean spots and he pretty much said it didnt look like it, there was consistant buildup of carbon throughout.

He's saying maybe my fuel pressure tester is shit...(from AutoZone) but I doubt it. I'm thinking he didnt bother to locate the source of the 54psi after he saw that the pressure was now staying in the line.

I'm going to check the return line again tonight when I get home around 430pm. I'll post my results.

The trucks new fuel gauge doesnt seem to be completely accurate either. Kind of a let down. Maybe all the pumps for our vehicles have a little play in the sender unit? I dont know. Still no sign of surging.

10-4 On you can not run it with the cover off.
But you can jumper the fuel pump and watch for external leakage and with fuel pump jumped the pressure reg should hold and regulate 65-66 lbs of fuel pressure at the fuel rail with the fuel pump running.
And while it is running you can pinch off return fuel line and the pressure should jump to 75-85 lbs of pressue. Just do not let the fuel pump run over 30 seconds at that full pressure.
When the pressure jumps to 75-85 lbs unplug fuel pump jumper. And then recheck regulator for external leaks.
But in your case if the new fuel pump is putting out good pressure and the fuel pressure on fuel rail is not up to par and it will jump up if you pinch return line off the regulator is not holding the right pressure.
You might as well get a new one for it.
MT

I dont know if yours hads went this far gone. but my regulator leaked to the point where it ended up dumping 1ltr of gas into my oil when it finaly pop'd ..

easyest way to tell is take the plenum off and get someone to turn the key on and watch it presure up.. we knew what had happend right away when it"gas" spit out the side of the regulator.

Ive seen sites where you can buy the regulator replacement but most places will want you to buy the whole "spider" setup. you can get them like 300 rebuilt/refurbished.

I know the "vacume leak" sound you speak of. sounds verry similar to me my truck. used to start good in the mornings but if i drove it down town shut it off it, I would have to wine over to start. its worth a look. 10$ gasket and just tighten it back to spec if you see nothing wrong.

what vac leak are you referring to

ugh, no progress yet.

I did try to pinch the return line off again, but this time when I looked at the rubber line I'd pinched off in the beginning, it doesnt really look like its a return line from the engine.....more like a loop from and to the tank. But its gotta be it, as its the only short bit of rubber tube there.

The guy working on the car hasnt pulled the upper cover to look at the regulator again yet. I think I'll tell him to do that with the key on now that the pressure is up, and see if he sees ANY signs of leakage. He said he didnt want to replace the regulator and have that NOT be the cause...and also brought up the common leak with the spider assbly in there. I'd assume he'd be able to locate the leak if it was one or the other with the cover off right? I can smell fuel (but cant tell where from) at times, and my gas mileage is at an all time low. Im talking easily single digits. I live 15 minutes from work, no traffic, and driving at approx 55-70mph, I can literally see the drop in gas by the time I've arrived. I'm hearing a slight pop in the exhaust when you goose the accelerator (like raw fuel is getting in the exhaust), and a small puff of smoke was seen this weekend on a single start up. It also surged more today......which seems to be consistant with the wet weather once again.

Chevy Dealer told me that it is possible for the fuel to be getting into the exhaust if one or both of these were leaking. I dont really know what else to do other than to take the top off, and replace the regulator. Its the cheapest fix. $90/regulator from Dealer, $60/from Autozone.

Anything setting off a light with you guys here? These symptoms point to anything? HELP?

ugh, no progress yet.

I did try to pinch the return line off again, but this time when I looked at the rubber line I'd pinched off in the beginning, it doesnt really look like its a return line from the engine.....more like a loop from and to the tank. But its gotta be it, as its the only short bit of rubber tube there.

The guy working on the car hasnt pulled the upper cover to look at the regulator again yet. I think I'll tell him to do that with the key on now that the pressure is up, and see if he sees ANY signs of leakage. He said he didnt want to replace the regulator and have that NOT be the cause...and also brought up the common leak with the spider assbly in there. I'd assume he'd be able to locate the leak if it was one or the other with the cover off right? I can smell fuel (but cant tell where from) at times, and my gas mileage is at an all time low. Im talking easily single digits. I live 15 minutes from work, no traffic, and driving at approx 55-70mph, I can literally see the drop in gas by the time I've arrived. I'm hearing a slight pop in the exhaust when you goose the accelerator (like raw fuel is getting in the exhaust), and a small puff of smoke was seen this weekend on a single start up. It also surged more today......which seems to be consistant with the wet weather once again.

Chevy Dealer told me that it is possible for the fuel to be getting into the exhaust if one or both of these were leaking. I dont really know what else to do other than to take the top off, and replace the regulator. Its the cheapest fix. $90/regulator from Dealer, $60/from Autozone.

Anything setting off a light with you guys here? These symptoms point to anything? HELP?

Blazee/MT -

should I just go ahead and try with the regulator first here? If I do the pressure pinch test, its going to show an increase most likely whether its the regulator or spider assmbly. I can smell strong fuel inside the intake. I just wish I could rule one or the other out before I go and replace it.

ugh, no progress yet.

I did try to pinch the return line off again, but this time when I looked at the rubber line I'd pinched off in the beginning, it doesnt really look like its a return line from the engine.....more like a loop from and to the tank. But its gotta be it, as its the only short bit of rubber tube there.

The guy working on the car hasnt pulled the upper cover to look at the regulator again yet. I think I'll tell him to do that with the key on now that the pressure is up, and see if he sees ANY signs of leakage. He said he didnt want to replace the regulator and have that NOT be the cause...and also brought up the common leak with the spider assbly in there. I'd assume he'd be able to locate the leak if it was one or the other with the cover off right? I can smell fuel (but cant tell where from) at times, and my gas mileage is at an all time low. Im talking easily single digits. I live 15 minutes from work, no traffic, and driving at approx 55-70mph, I can literally see the drop in gas by the time I've arrived. I'm hearing a slight pop in the exhaust when you goose the accelerator (like raw fuel is getting in the exhaust), and a small puff of smoke was seen this weekend on a single start up. It also surged more today......which seems to be consistant with the wet weather once again.

Chevy Dealer told me that it is possible for the fuel to be getting into the exhaust if one or both of these were leaking. I dont really know what else to do other than to take the top off, and replace the regulator. Its the cheapest fix. $90/regulator from Dealer, $60/from Autozone.

Anything setting off a light with you guys here? These symptoms point to anything? HELP?

On replacement parts remember OEM dealer parts only hurt one time.
That el cheapo aftermarket stuff can bite you in the rear many times.
:grinyes: :lol:

Proper testing step by step will tell the story on it.
The return line is the small line from the engine down by fuel filter.
The large line from filter to engine is the pressure line.
Just pinch off the return line on the rubber part of hose.
If pressure jumps up to fuel fuel pump pressure/75-85 lbs of pressure with return line pinched off that tells you the fuel regulator is bypassing to much if pressure does not hold but 55 lbs with return line not pinched off.
Make sure the fuel pump is putting out good pressure first thing. By pinching off return line.
Then check the fuel regulator for leakage and bypassing pressure.
And if it is bad get the regulator from the dealer.
Remember OEM dealer parts only hurt one time.
The 98 does not have a common leak on the spider assembley.
Not even a spider assembley. Each injector is seperate.
Run all of the fuel pressure test and then go for it.

After you get fuel pressure up to par there is a injector balance test that can be done with a good engine capable scanner. But you will have to have good fuel pressure first to run it.
MT

might be worth noting as well.

when you actuate the throttle from under the hood with the engine running, the two fuel lines that enter the top of the intake look like they're jumping up each time the throttle is goosed, and a strong vacuum sound can be heard from it.

Is that normal?

might be worth noting as well.

when you actuate the throttle from under the hood with the engine running, the two fuel lines that enter the top of the intake look like they're jumping up each time the throttle is goosed, and a strong vacuum sound can be heard from it.

Is that normal?

The fuel lines that go in there are both under fuel pressure. Big One the in line and small one return. They should not be lose or leaking.
That may explain the gas smell.
They are held down with one screw and a clamp that fits over the shoulder on fuel lines.

The vacume leak noise would be another problem. There is a seal around the injector body where the fuel lines and wiring goes into intake.
Check for vacume leak there and other places on intake.

If your mechanic had the intake off he is the last person that worked on it.
Are you going to fix it yourself or take it back to him to finish up the job?
MT

The fuel lines that go in there are both under fuel pressure. Big One the in line and small one return. They should not be lose or leaking.
That may explain the gas smell.
They are held down with one screw and a clamp that fits over the shoulder on fuel lines.

The vacume leak noise would be another problem. There is a seal around the injector body where the fuel lines and wiring goes into intake.
Check for vacume leak there and other places on intake.

If your mechanic had the intake off he is the last person that worked on it.
Are you going to fix it yourself or take it back to him to finish up the job?
MT

I just went and bought the regulator from the dealer for approx $90. Will I need a gasket for this upper plastic intake cover when I reinstall? I planned on tackeling the job tonight when I get out of work, why do you ask? Frankly I'm tired of the hassle with the mechanic I was using, and have little faith in his ability. These symptoms I've mentioned of a vacuum sound ("pfffft"), and jump on each goose is not supposed to be heard? I just tried to tighten the screws, and it didnt make a difference. Its not just the lines, its the whole "fuel meter body" that they attach to thats moving/making the noise. It only does it on a hard quick goose of the accelerator. Similar to the sound the air intake makes. Should I assume the seal around the injector body needs to be replaced? Or is the regulator part of what could cause this? I just called the dealer, the seal only comes as a kit with the lower intake gasket etc.
Could someone with a 98 style Blazer check this on theirs? Do you hear a vac. sound when you goose the accerator, or see any movement in the two lines entering the intake? I'm going to spray it with a small amount of starting fluid to see if it sucks in and changes the rpms.

The reason I as.ked was it sounds like the mechanic done messed it up.
If you are going to do it yourself get the intake gasket and seal set.
It actually sounds like the seal was left off or fell of of the injector body.
if the seal was on there the injector body would be fitting sung in the intake.
With no vacume leak.
If the fuel lins are lose or leaking see if the dealer has the seals and plastic bushings for the lines. There is several seals and washers/bushings for each fuel line.
The dealer should have a good picture of them. Have him print it off for you.
Nothing like fixing something after someone has messed it up.
Good luck
And let us know how it goes.
Mt

The reason I as.ked was it sounds like the mechanic done messed it up.
If you are going to do it yourself get the intake gasket and seal set.
It actually sounds like the seal was left off or fell of of the injector body.
if the seal was on there the injector body would be fitting sung in the intake.
With no vacume leak.
If the fuel lins are lose or leaking see if the dealer has the seals and plastic bushings for the lines. There is several seals and washers/bushings for each fuel line.
The dealer should have a good picture of them. Have him print it off for you.
Nothing like fixing something after someone has messed it up.
Good luck
And let us know how it goes.
Mt

Along with the regulator; I actually picked up the full gasket set (which includes the throttlebody gasket/upper intake cover gasket, and the one we're mentioning) just in case, as well as a second kit for the plate that the system screws into (which includes fuel line o-rings etc) at $30 a piece. I'll return it/them unopened if they're not needed. If I do a job I know its done right, not half ass. Last thing I want to do is get into it tonight and find out I'm without a simple piece that needs to be replaced (after the dealer is closed). I'm hoping just the gasket came off as suggested, and thats where the vac. leak/movement is coming from (as opposed to the mounting bolts that secure it) Would you think the seal itself, if missing, would allow that extra movement? It might have been this way BEFORE he even took off the cover, I'm not sure. But I couldnt detect any change in RPM with the starting fluid. Regardless, I'll replace anything that's suspect.

Along with the regulator; I actually picked up the full gasket set (which includes the throttlebody gasket/upper intake cover gasket, and the one we're mentioning) just in case, as well as a second kit for the plate that the system screws into (which includes fuel line o-rings etc) at $30 a piece. I'll return it/them unopened if they're not needed. If I do a job I know its done right, not half ass. Last thing I want to do is get into it tonight and find out I'm without a simple piece that needs to be replaced (after the dealer is closed). I'm hoping just the gasket came off as suggested, and thats where the vac. leak/movement is coming from (as opposed to the mounting bolts that secure it) Would you think the seal itself, if missing, would allow that extra movement? It might have been this way BEFORE he even took off the cover, I'm not sure. But I couldnt detect any change in RPM with the starting fluid. Regardless, I'll replace anything that's suspect.

You are on the right track.
When you get the intake off you will see the injector body is on a floating/sliding type of bracket on the bottom of it.
The seal on top of it where it goes into the intake holds the top of it in position.
When you put the intake back on oput a little lubercant on the seal and intake where it goes in.
Good luck and let us know how it goes.
MT

You are on the right track.
When you get the intake off you will see the injector body is on a floating/sliding type of bracket on the bottom of it.
The seal on top of it where it goes into the intake holds the top of it in position.
When you put the intake back on oput a little lubercant on the seal and intake where it goes in.
Good luck and let us know how it goes.
MT

I'm mid-job right now. Taking photos for a HOW-TO to be posted later

OK, top is off, and these are my findings. MT, if you're looking at this and can help. I'd greatly appreciate what this photo tells you. The three injectors on the passenger side have a small reserviour above them that are vented. All three have liquid pools in them that smell more like oil than gas...but I could be wrong. The injector closest to the firewall had the most in it. Please get back to me asap, you can call me if you feel up to it. thanks
J
http://www.geocities.com/rudemoodz2001/leak2.jpg

OK, top is off, and these are my findings. MT, if you're looking at this and can help. I'd greatly appreciate what this photo tells you. The three injectors on the passenger side have a small reserviour above them that are vented. All three have liquid pools in them that smell more like oil than gas...but I could be wrong. The injector closest to the firewall had the most in it. Please get back to me asap, you can call me if you feel up to it. 401 787 3176
thanks
J
http://www.geocities.com/rudemoodz2001/leak2.jpg

I do not see that is is anything to worry about on it. They are more or less dead spots that collect fuel and oil. May not look good but will not hurt anything.
Just sponge the old gas and oil out.
MT

I do not see that is is anything to worry about on it. They are more or less dead spots that collect fuel and oil. May not look good but will not hurt anything.
Just sponge the old gas and oil out.
MT


ok, can you give me a call and I'll write everything down after on the howto/findings? it'll take me two minutes to explain what I have and maybe you can tell me what to do ?

The regulator showed no signs of leaking...but underneath the spider assembly, all 6 ports seemed to have fuel in them, as if they were all leaking. Is this common?
http://www.geocities.com/rudemoodz2001/spider.jpg

Should I wait till tomorrow and replace all 6 lines? Or at least their 2/orings per injector? And also, the question regarding the vac leak in the spiderassembly...the bolt that holds the bracket is secure, but theres free movement in the bracket itself. Thanks
Like I said...please give me a call asap..Im waiting to continue.

The fuleregulator is on the left side of the engine if your leaning over the hood "towards window from grill" if you have one side super clean looking "gas washes down oil" and one side of the plenum oil covered like in your pick that also would tell me its leaking.

you can turn your key on " DONT START IT " have someone just turn the key and watch the regulator for a leak. if it presures up and no spray.. aswell as your left side of the plenum when your faceing over the hood looking in is not washed looking. its probly not doing anything major if anything at all. then your problem most likely lies elsewhere..

you will probly need a dif torks bit, one with a hole in the center to get that regulator off the spider if i remember correctly.

thanks for the call MT. I'm going to try to just replace the 12 Orings on the injectors...as the approx $75/each to replace the injectors...is WAY over my budget.

cross your fingers! I'm going to try to ask one of the techs at the dealership if they think anything is wrong where those ports had pools in them. Something seems wierd there....but I hope you're right that its normal.

I'll report back on the Orings etc.

I'm livid.
Got it all back together after replacing the regulator, and injector o-rings, and now not only is the pressure still at 54psi, but its running horrible, and I got a trouble code indicating a problem with cyllinder #2. This is one of the three from the passenger side that'd shown the excess pooling of liquid in the vent above them. I'm thinking I need to just replace all the injectors....but its rediculously expensive. $100 approx. each.
I'm so pissed. anyone got help, or ideas?

I've found two places that sell the injectors for much less.

What do you think? I know anyone is going to say buy the injectors new from the Dealer etc. but I don't have another $600 to spend. Thanks

If you have a code for miss on no 2 cylinder you have a problem on no 2 injector.
Did you check fuel pressure and check for leaks before you put it back together?
Does the fuel pressure leak down or hold steady?
Are you sure your fuel pressure gauge is right?
Check it on another vechicle just like yours or with another gauge.
And last but not least you need to check the direct or full pressure on the fuel pump.
You need to make sure it is putting out full pressure of 75-85 lbs of fuel pressure.
What is the fuel pressure with the return line blocked/pinched off?
If fuel pump and gauge is working right it should jump up to 75-85 lbs with return pinched off. Does it do that?
MT

If you have a code for miss on no 2 cylinder you have a problem on no 2 injector.
Did you check fuel pressure and check for leaks before you put it back together?
Does the fuel pressure leak down or hold steady?
Are you sure your fuel pressure gauge is right?
Check it on another vechicle just like yours or with another gauge.
And last but not least you need to check the direct or full pressure on the fuel pump.
You need to make sure it is putting out full pressure of 75-85 lbs of fuel pressure.
What is the fuel pressure with the return line blocked/pinched off?
If fuel pump and gauge is working right it should jump up to 75-85 lbs with return pinched off. Does it do that?
MT


yea MT, if you read my latest post you'll see my situation got a lot worse today. I dropped a nut from the fuel line into the lower intake. So I have to remove the intake now to try to retrieve it.
As far as the cyllinder #2, I figured that was probably one of the cyllinders that was leaking. Probably filling with extra fuel and that caused the code. Who knows, I may have worsened the leak when I was changing Orings, or pulling on the injectors to remove them. My plan was to recharge the pressure and check with the cover off.......and was in the process of reconnecting the lines when I dropped the nut in. So now I'm screwed. Got to fix my new problem before I go on to the next.

yea MT, if you read my latest post you'll see my situation got a lot worse today. I dropped a nut from the fuel line into the lower intake. So I have to remove the intake now to try to retrieve it.
As far as the cyllinder #2, I figured that was probably one of the cyllinders that was leaking. Probably filling with extra fuel and that caused the code. Who knows, I may have worsened the leak when I was changing Orings, or pull on the injectors to remove them. My plan was to recharge the pressure and check with the cover off.......and was in the process of reconnecting the lines when I dropped the nut in. So now I'm screwed. Got to fix my new problem before I go on to the next.

Ouch on that.
Good luck without all of the bad luck
MT

I'm assuming this is a sign of the surging problem when its moist out??? It's like a chalky residue.....
I've already replaced the wires in an attempt to fix this....to no avail. Does this look abnormal? The cap is about a year old.

http://i16.photobucket.com/albums/b40/JoshB_/distributercap.jpg

Have you got any other symptons or is your engine running OK?


Mark

I did a full tune up, including cap and rotor at 115,000 and mined looked the same way. on my cap, the metal ends looked preety ceroded. i didn't think twice and just replaced them. Ive haven't had a problem before or after i changed them

Josh, if possible can you reduce the picture size before you post them. It's a pain for people on dial up to download them, and that picture is just so big that it's almost tough to focus on.

It's a pretty comon thing. There's a magnetic field in the distributer that is the most likely cause of it. I've never seen it cause any problems before.

Although I've never seen the carbon deposits on the inside of a distributer cap look anything like yours, so that might be a problem. They always face the center of the distributer not multi directions.

if there isn't a driveability issue quit tryen to fix it lol

if there isn't a driveability issue quit tryen to fix it lol

did you read the post or just look at the picture?

DM would have done both, he's really good that way. However he probably missed the surging problem part.

I just changed my distributer cap a few days ago, and I don't think that I've thrown the old one out yet. When I'm back on monday I'll take some pic's of it, it I think of it and post them

DM would have done both, he's really good that way. However he probably missed the surging problem part.

I just changed my distributer cap a few days ago, and I don't think that I've thrown the old one out yet. When I'm back on monday I'll take some pic's of it, it I think of it and post them


explain what you meant by "in all directions" in your first response?
this shit is really chalky, as you can see where I whiped my finger across part of it

Have you got any other symptons or is your engine running OK?


Mark

Just the surging in moist or wet weather

As you can read/view pix in my other post titled "Dropped Nut into Intake", I had to remove the lower intake, and retrieve the nut from one of the cyllinders. Very long.....very unpleasant......lesson learned....PLUG YOUR INTAKE PORTS IMMEDIATELY!

As far as the fuel problem...I was in the process of hooking the fuel lines back up with the cover off to look for leaks when the nut was dropped so it all was put on hold.

After careful inspection of the spider assembly removed, the underside, which originally looked like this:
http://www.geocities.com/rudemoodz2001/spider.jpg
was now good and dry after the replacement of the injector O-rings. Granted, it was only driven one day after that...and still may leak...but the fact that the car still held only 54psi, and I had a code telling me there was a problem with Cyllinder #2 misfiring, I'm assuming at least the #2 injector is leaking inside the cyllinder, if not others.

Rather than replace an injector at a time, which from the dealer is $100/ea (you cant buy the full set), so it'd be over $600 for them all....I've found a few places online that sell rebuilt systems. You can buy the full set of 6 (or 8 depending on your vehicle) thats made up of new and rebuilt parts....at about half the price.

AutoCraft 1(800) 550 1424
sells full spider assembly for: $299.95 + $100(core)

50 MotorSports 1(562) 394 7218
sells full spider assembly for: $199.50 + $60(core)

I opted for the AutoCraft, as they'll be here by Tuesday. I'll install those and recheck pressure. I'm pretty sure that it should fix the problem of HORRIBLE gas mileage, misfires detected (Im assuming it may send a code if the injector is leaking?), and a 10psi fuel pressure leak (after regulator and fuel pump replacement)

On a side note.. if you look at the photo below (mentioned earlier in this thread) showing the ports along the passenger side of the intake that contained liquid, I found out while cleaning the intake, that these vents mentioned are vents for the EGR system. So the liquid collecting in these was not directly from the injector, but from the EGR system.
http://www.geocities.com/rudemoodz2001/leak2.jpg

replaced it with the new assembly. its amazing...but GM didnt list that part number in there computer system to come up when you search for the spider assembly for my vehicle. here's what I think happenend. GM realized the original injector system was a POS. They frequently got stuck either open or closed......surprisingly, even though so many different years and models used this system, they never recalled it...but came up with this NEW injector system.

Sooooo........

They stopped making/selling the old system as a whole...but instead continue to sell the individual injectors for it. So if you have a single bad injector on the original system, you can replace it for about $100.
What's so odd though...is that you can order this NEW IMPROVED spider assembly as a whole, for under $300 with the regulator included. I told the dealer they should make a note of that......because until I gave them (and other dealers) the exact part number for the new spider assembly, they had no full assembly available for my vehicle....only single injectors. Don't know if its an intentional mistake by GM to rape customers at $100 per injector, or if its just a screw up in the way their listing is.

Thanks to Blazee for the info!

Here's the part numbers:
12568332 - MFI Assembly
88894355 - Bracket
17113215 - Seal kit

But, the bottom line is, I bought the new fuel spider. The gasket kit, I'd already purchased when I was trouble shooting...it includes the gasket for the throttle body, the gasket for the upper intake cover, and the gasket for the fuel spider where it seals inside the cover (seen below in orange).
The bracket IS different from the original, and although it appeared to be similar enough to use the original, its not. The NEW injector lines are thicker then the originals, and the bracket needs more clearance for them all to fit in. Once all the injectors are inserted, they put slight pressure on the fuel spider in the direction of the firewall...which keeps the bracket seated firmly.

http://i16.photobucket.com/albums/b40/JoshB_/18.jpg

Cross your fingers that this takes care of my horrible MPG...unless my pressure gauge is wrong, my pressure is still only 54psi after the new fuel pump, fuel filter, fuel line o-rings, and new spider assembly/regulator. Go figure~!

I'll report back after I have a better idea on if it fixed the symptoms