Hard start / dies when hot.

The latest gremlin to appear on my 1992 Park Ave. Non Supercharged w/ 63,000 miles, is a hard start, sometime stall condition when hot.

When hot, it has to turn over quite a bit to get the engine started. If I don't step on the throttle a little once it starts it will immediately die.

On 2 occasions, one of them being today, after I have been sitting stopped and idling, at a drive through lane at a fast food restaurant for example, when I let my foot off the brake and start to pull away the engine has died.
No hesitation, nothing, just dead.
Then, I go through the routine in starting it I mentioned above all over again and it will run fine.
Doesn't matter if the AC is on or not.

Maintenance items that have been done over the past year other than fluids.
New AC plugs.
New AC Plug wires.
New fuel filter about 90 days ago.
New coil pack and ignition module to correct a rough running / stutter problem.
At the time I was diagnosing the rough running / stutter problem, I tested fuel pressure and it was within spec at 45 lbs. (If I recall correctly)
No codes are ever stored when I check.

As a cheap, what the heck solution, I have run a can of injector cleaner through it.

Any ideas before I spend the money for a shop to diagnose it?
I am for the most part a do it myself guy and have both the mechanical & electrical factory service manuals for the car. Though, they aren't as layman friendly as they used to be.
The only thing I have used shops for in 31 years of driving is tire mounting and balancing.
But I digress.

Thanks in advance!

Dale

well i see you never had your maf sensor check.but when it gets hot a dies could even be your coilpack that sets on top moduler.

well i see you never had your maf sensor check.but when it gets hot a dies could even be your coilpack that sets on top moduler.

No, haven't checked the MAF sensor.
Both the coil pack & ignition module are less than 60 days old though.

The maf could cause this, so can the crank sensor.

You might want to try cleaning the MAF sensor wire with MAF cleaner before testing. Of course, a scan tool is the best method of testing. A full function scanner will show air flow in terms of grams of air per second (gps), with a range from 3gps to 150 gps. The MAF sensor produces a frequency output between 32 and 150 hertz.


The harness to your MAF sensor is three wires labeled A, B, and C. (it is that thing near the air intake area) It has a pink/black wire (C), a black/white wire (B), and a yellow wire (A). Wire C goes to a fuse in the relay center under the passenger side dash. Wire B goes to ground. Wire A goes to the PCM.

First thing: check the wires and harness for trouble.

Second: disconnect electrical connector, turn key to ON position, engine stopped. Read voltage between wire A and ground. It should be between 4-6 volts. Is it? If yes, connect test light between wires B and C. Light should be on. Is it? If yes, you have a faulty MAF sensor connection or sensor. If no, connect test light between C and ground. Test light should be on. Is it? If yes, the ground wire (B) has an open. If no, the pink/black wire (C) has an open.

If the voltage was not between 4-6 volts above:

If it was less than 4 volts, either the yellow wire (A) is open or shorted to ground, or you have a faulty PCM.

If it was more than 6 volts, the yellow wire (A) is either open to voltage or you have a faulty PCM.

connect test light between wires B and C. Light should be on. Is it? If yes, you have a faulty MAF sensor connection or sensor. If no, connect test light between C and ground. Test light should be on. Is it? If yes, the ground wire (B) has an open. If no, the pink/black wire (C) has an open.

I'm confused.
If in both cases, the test light should be on, and it is, that indicates trouble?
Did you mean to say the light should be on, but if it isn't that indicates trouble?
Can you clarify please?

Otherwise, you have given me clear directions for testing. I will check it out tomorrow.

I appreciate your help! :)

Did you mean to say the light should be on, but if it isn't that indicates trouble?
Can you clarify please?
Either way could indicate a problem!

Wire A goes to the PCM.
Wire B goes to ground.
Wire C goes to a fuse in the relay center under the passenger side dash.

Remember, you are checking for proper voltage going to the MAF sensor. If the voltage checks ok going to the MAF, then you have a problem with the MAF. If not, you have wiring, connector, fuse, or PCM problem. Read the instructions several times, for a better understanding of the procedure.

Ok, checked it out.
Voltage between wire A & ground is 5.02 volts.
Test light between wires B & C results in test light being on.
Test light between wire C & ground results in test light being on.

The procedure made more sense to me when I found the flow chart in the service manual for it.

It also mentions the throttle position sensor binding, or having a high voltage signal with the throttle closed. "Should read between .33 - .46 volts @ 0% throttle angle."
Or, the coolant temp sensor.
What are your thoughts on these being the cause?
Is there a way to check these using a multi meter?

Man, I am surprised by how much a MAF sensor costs! About $140.00 for a rebuilt one with a $70.00 core.
Wish I had access to a known good one to swap out to be certain it is the cause before buying one.


I appreciate the help!

Update.
My neighbor let me swap in the MAF sensor from his Olds 98 for test purposes, and what a difference! :runaround:
Fires right off, and when idling at a light the engine is so smooth you would think it wasn't running.
Now I feel better about spending the money.

Thanks for all the help!

I was about to ask when you were planning to change the MAF! :sunglasse Anyway, we appreciate the feedback and I hope that this thread will help save others alot of time and frustration. :)

It's nice to have spare MAF; I found they are somewhat specific to the engine model. If you can match part numbers, all the better. I think they all start with AFH50M, but the last 3 digits indicate a certain engine application curve. And I'm sure that's why they cost so much.

I my situation, I tried using a MAF from a junked non-supercharged '3800 on my '92 PAU. The numbers were pretty close, when I used it on my supercharged engine, boy did I see performance problems....mostly under hard acceleration and a Code 57 popped up out of the blue.

I came across a listing on another forum as to what fits what; sorry, I don't have the link.

I'll pay attention to the part # when I go to the yard this weekend.

I did notice that for an aftermarket sensor from Autozone for example, shows the same part # for both the Supercharged, and non supercharged.

I have a feeling they are calibrated (if that's the word) as a compromise between the 2, and not the way GM would have intended.

Below is the table I was referring to earlier..I did not send the original link for fear of "advertising" the site. This is probably easier anyway. BTW, it was a site devoted to Bonnevilles. Now, the original MAF on my PAU is a '02C. I pulled a '02E from the junkyard and had troubles. I thought I got one from a '92 but at this point who knows. Good Luck!

http://i98.photobucket.com/albums/l266/psue_1984/buick/3800-maf.jpg

I guess I'm on a roll on this issue....I checked the AC Delco web site for the part and the MAF for a '92 PA is either 213-230 or 213-1619. For the '92 PAU the number is a 213-231 or 213-1620. I didn't check Rock Auto, but they're pretty good on the cross references. Anyway, be careful.
Also, at my junkyard the MAF modules seem to go quickly. There usually isn't one on any of the cars that have been there for a while. I hope you find one.

I guess I'm on a roll on this issue....I checked the AC Delco web site for the part and the MAF for a '92 PA is either 213-230 or 213-1619. For the '92 PAU the number is a 213-231 or 213-1620. I didn't check Rock Auto, but they're pretty good on the cross references. Anyway, be careful.
Also, at my junkyard the MAF modules seem to go quickly. There usually isn't one on any of the cars that have been there for a while. I hope you find one.

Yeah, I'm not sure I will find one at the yard, but what the heck?
Some yards pull parts like these and have them on a shelf.

But, I need to find a couple of other parts like the chrome bumper strips / trim that run along the quarter panel.
My car is in great condition except for these.
It was a little 'ol lady car with 30,000 miles on it 3 years ago when I bought it.
Why is it that on all the trashed & rusty Park Avenue I see, these chrome strips are in nice shape while mine have rust holes in them? :banghead:

I haven't gone yard scrounging in a long time so I am looking forward to it.
So many yards I used to go to are long gone and housing developments now stand in their place. :crying:

Any ways, thanks for the info.
Was that site you mentioned the Pontiac Bonneville Club forum?

Why yes it was PBCF; not long ago I included a couple of cross forum links and got chided for it. No big deal.
I have some bumper trim on mine that I'd love to find a replacement at the yard. It's the plastic wrap-around strip. On the right side of the front bumper it's torn and sort of hanging down. It will be a mess if it comes apart. I love the car, I just keep putting off a trip to the body shop. Soon the headliner will be down.
The SC version is a blast to drive....with 250k on it I just got 27mpg on a trip to my mom's. All the best!

Update:

Replaced MAF sensor, removed and cleaned the throttle body and IAC valve.
(it was pretty crusty.)
Runs well, and gas mileage has improved.

Still has to spin over quite a bit before it starts though, compared to my Mother's '94 Park Avenue which you just tap the key into the start position and it fires off.

I've read about a sticky check valve in, or near the fuel pump.
What are thoughts on this being part of the problem?

Perhaps this is just how the car is, and I will have to live with it. But if I can cure it all the better.
Especially with winter approaching the less cranking the better.

The car has always had this threshold of -12*. Any colder and forget it. :disappoin

well have you replaced cps since you've had it? and have you had your fuel pump tested latley? a air filter could cause that to. and you might want to take hose off and spray that little butterfly in the multiport fuel injectshon they tend to stick if not cleaned with the spray.because also yours should just be bumped to get it started like you say your moms pa bump and it takes right off.good luck........

well have you replaced cps since you've had it? and have you had your fuel pump tested latley? a air filter could cause that to. and you might want to take hose off and spray that little butterfly in the multiport fuel injectshon they tend to stick if not cleaned with the spray.because also yours should just be bumped to get it started like you say your moms pa bump and it takes right off.good luck........

From my first post.

"Maintenance items that have been done over the past year other than fluids.
New AC plugs.
New AC Plug wires.
New fuel filter about 90 days ago.
New coil pack and ignition module to correct a rough running / stutter problem.
At the time I was diagnosing the rough running / stutter problem, I tested fuel pressure and it was within spec at 45 lbs. (If I recall correctly)
No codes are ever stored when I check."

I failed to mention the air filter, but it is fairly new also.
Throttle body has been cleaned.

CPS? :confused:

Still has to spin over quite a bit before it starts though, compared to my Mother's '94 Park Avenue which you just tap the key into the start position and it fires off.
Try a double pump prime before starting; turn the ignition switch ON until the fuel pump primes and shuts off, (usually 2-sec) then turn OFF ign switch. Repete the same procedure and wait 2-sec then start. Let us know what happens.

Try a double pump prime before starting; turn the ignition switch ON until the fuel pump primes and shuts off, (usually 2-sec) then turn OFF ign switch. Repete the same procedure and wait 2-sec then start. Let us know what happens.

Gave it a shot.
It still spun over quite a bit before starting. Perhaps 3-4 seconds, and once it started it acted as though it wanted to die until I gave it a little gas to keep it running.
Once running, if I shut it off and turn the key again immediately, it pops right off.

and once it started it acted as though it wanted to die until I gave it a little gas to keep it running.Actually, if you open the throttle, you are giving it air, not gas. What is your TPS voltage on the blue wire @ closed throttle? Will it start quicker with the throttle partially open? Personally, I could not tolerate an engine that did not start within 1-sec! :shakehead

Actually, if you open the throttle, you are giving it air, not gas. What is your TPS voltage on the blue wire @ closed throttle? Will it start quicker with the throttle partially open? Personally, I could not tolerate an engine that did not start within 1-sec! :shakehead
Ahh yes! you are correct! adding more air is what I am doing.
You knew what I meant though.
It will start quicker if I partially open the throttle as I crank it over.
Over time this is what I have done without really realizing what I was doing.

I'll have to check that voltage tomorrow. What range voltage should I be looking for?
And yes, it has been very annoying to live with.

I can go out to my garage right now and with one pump and a turn of the key my '70 Riviera will start right up and run smoothly even when it has sat for weeks!
I am far better at performance tuning a Quadrajet than I am fuel injection.
'ol school ya know. :iceslolan

Thanks for all your help and education on doing these diagnostics!
http://www.fadzter.com/smilies/beerchug.gif

(Hope it's ok to add smileys not provided by the board)

I'll have to check that voltage tomorrow. What range voltage should I be looking for? You should have .45 to .55 @ closed throttle. Do you have a scanner?

You should have .45 to .55 @ closed throttle. Do you have a scanner?

No, just a multimeter.

maybe a cps or coil so what you say now.lol.oops maybe fuel pump getting hot and ready to go.

You should have .45 to .55 @ closed throttle. Do you have a scanner?


Checked the voltage this morning.
It was at .52 volts.
My Buick service manual says it should be between .38 - .42 volts with the throttle closed.
I adjusted the TPS so the voltage was right at .40
While it started and ran, I will have to drive it today to see if it made any improvement.

So far, so good after adjusting the TPS.
The car seems more responsive and starts much faster.

I really need to pick up a scanner for future troubleshooting.

Thanks!

Well, I was still having a problem with it stalling when I let my foot off the gas, and it idling slow. (400 rpm in drive.)
I have been driving around the last couple of weeks with my eye on the tach whenever I had to let my foot off the throttle to catch it when the tach needle would drop abruptly.
I could blip the throttle a little to prevent the stalling and the RPM's would recover.
This is usually an issue when making a turn at a stop sign after sitting at idle for a few minutes, accelerating from a stop, and then letting off a little while making the turn, though I can sometimes induce it while going down the road.
Never when cold, just after the engine is to full temp. I imagine it runs fine cold since it is in open loop mode.

After doing much research, it logically seemed to point to a sticking, slow responding idle control valve.

(There never have been any codes stored, or any service engine light activation.)

Yesterday I picked up a new IAC valve and installed it last night.
In test driving last night, and driving to work this morning the abrupt drop of RPM's when de accelerating seems to be cured, but it still idles at 400 in drive.
(I was able to make it stall, but I was really trying. :biggrin: )

At what RPM is considered normal? 400 seems a couple hundred low in my mind.
Is there any way I can physically raise the idle to 550-600?

Also, I am wondering how does moving the TPS setting one way or another effect performance?
Is it better to be on the high side? (.42 volts) or low side of that setting? (.38 volts)
As mentioned earlier, I have my TPS set in the middle at .40.

Move it up to .45 or .48 if you can. RPM and throttle response will be better!

Move it up to .45 or .48 if you can. RPM and throttle response will be better!
Thanks! That is exactly what I wanted to know!

http://www.clicksmilies.com/s1106/ernaehrung/food-smiley-004.gif

Changing the TPS value helped throttle response, but didn't help idle speed.

Well, I thought all was well until today on the way home from work it stalled on me 4 times!:banghead:
Runs fine, until I let off the throttle and then dead. Starts right back up.
I've gotten good at putting it in neutral and re-starting without missing a beat.


I am now wondering if the EGR valve is suspect.

that still sais coil's or module or maf sensor can you smell gas when it does this moods it's in?

that still sais coil's or module or maf sensor can you smell gas when it does this moods it's in?

The coil, ignition module, MAF, Idle control valve, PCV are all brand new in the last 4-5 months.

have you pulled harmontic and checked the cps? other than that i do not no unless map sensor.

have you pulled harmontic and checked the cps? other than that i do not no unless map sensor.

No, that would be last resort. But is in the back of my mind.
Is it really a big deal to line that sensor up without the special GM tool?

Anyone know what a bad harmonic balancer sounds like?

I have had what sounds like a sheetmetal heat shield rattle at light throttle when driving for a long time now, and haven't been able to narrow down where it is coming from since it doesn't make the noise when idling.
Just curious.
I would think if the rubber in it had broke and the outer ring shifted, I would have a rough running, out of time engine.

if it was balancer you would know it because sounds like a big big nock.but thats not what i said earler cps is behind that balacer.

My 99 PAU has a rattle that might be described as a light sheet metal rattle. It is most predominant at 1300-1500 rpm, but can sometimes be heard from 1200-1600 rpm. It can only be heard under load (as opposed to park or neutral with enough accelerator to bring it up to those rpm), and while I don't know, I am guessing it is just one of the catalytic converters broken loose in the exhaust. If yours does it in park/neutral as well (and just as loud), though, it is probably something else.

do you no anyone that works for a shop or dealer? maybe they can get it for you? it is easy to line up with the cps tool. i don't no it you want to do this but you can set them with brass fealer gage. if you do it your self dont forget to use locktite because ones it's in line with the jaws cps goe's into and it will loosen up with no locktite and there goe's a new cps again again.

good luck.....

scrapper1

All 93-up Vin-L & Vin-K & Vin-1 use the CKPS shown below. No adjustment necessary! It is aligned with a dowel pin and two bolts. Be sure the reluctor rings behind the balancer are straight & not bent!

http://img115.imageshack.us/img115/7229/1995ckpshe5.jpg

My 99 PAU has a rattle that might be described as a light sheet metal rattle. It is most predominant at 1300-1500 rpm, but can sometimes be heard from 1200-1600 rpm. It can only be heard under load (as opposed to park or neutral with enough accelerator to bring it up to those rpm), and while I don't know, I am guessing it is just one of the catalytic converters broken loose in the exhaust. If yours does it in park/neutral as well (and just as loud), though, it is probably something else. This is the typical sound of a loose or broken catalyst in the converter!

I'm crossing my fingers, but I think I cured my stalling problem.
First, I was looking closer at the throttle linkage, and did find a set screw for the throttle stop.
I turned it in about 3/4 of a tun.
Then, I did the idle learn procedure that I saw in another thread posted by Doorunrun.
Last night during a test run, and again this morning on my way into work I had absolutely none of the symptoms I have been having.
When I decelerate the tach needle comes down steadily with no abrupt drops or fluctuations up and down.

Time will tell for sure though.


This is the typical sound of a loose or broken catalyst in the converter!

That is my noise exactly!