just wont run right!!!!! 2001 cylinder 4 misfire

i just got a really good deal on a 2001 lincon ls v8 model. when i got it it had a misfire i took it and put it on a scanner and it read bank 1 lean bank 2 rich or the other way around i dont remember and misfire on cyl 2 and 4 i read on all the fourms about the cops going bad. well i replaced both of them and i put 2 new plugs in the 2 cyl that were misfiring. and while i was at it i checked the plugs that were in it and they wernt oil fauled or anything like that no signs of leaking valve covers. got it all back togeather erased the codes and drove it. still was misfiring. well scanned it again and it only came up as cyl 4 misfire. still to lean and rich. i pulled the coil out and put a extra plug in it and grounded it. started the car and it was sparking. so the coil and plug are good. i even pulled the injector out of the cyl that is misfiring switched it with another injector erased the code and guess what. still misfireing. im out of ideas. i bought a hand held scanner and a compression tester. i am out of ideas when it comes to this car.

PLEASE HELP

at a idle you can feel the car misfiring. but when your driving you dont really feel it. and the exaust smells a little rich.

Welcome to the forum!

Hopefully you are not discovering why you got such a good deal on the car....

Have you tried the compression tester yet to confirm cylinder #4 is close to having the same compression as the other cylinders? What brand of spark plugs did you install? Are you sure you are counting cylinders correctly? Cylinder #4 would be the passenger side nearest the firewall on your V8.

-Rod

yea fords go from the passenger side 1234 then driverside closest to the fan 5678 right? is loss of compression a commom problem with the 3.9?

You're correct on the cylinder numbering. I wouldn't say it's common for the 3.9L to have compression issues, but it's easy to check on this installation and inexpensive since you already have the tester. Ruling things out is important when trying to troubleshoot these types of issues.

-Rod

just did a compression test on cyl 2 3 and 4 were all above 170. those are the only 3 i did a compression test on. i thought for sure i wouldnt have any compression on number 4. would the compression test read low if a valve was sticking shut? but if that was the case the motor would be making some kind of noise wouldnt it?

Make sure the fuel injector signal + ignition signal wires to the COP cylinder 4 are getting good continuity signals,
the copper wire could break inside the insulation.

Also make sure, there's no extra fuel injector seals in the fuel rail going to injector 4.

does the rubber line going to the passengerside fuel injector rail just disconnect or pull off? thats for the suggestion about the clogged fuel injector rail. how would i check the contunity of the injector conector? i ohmed all the injectors them selfs and the ohm at 11 to 12 ohms. a bad sensor would cause a random misfire would it? thanks all of yall for all the help. i really hope i can figure this out.

i just went and sepent 68 on a new injector im gonna try replacing number 4 and blow the fuel rail out with compressed air real good and make sure theres nothing clogging it up.

put the new injector in and guess what????

still misfire hahahhaha


before doing that i relieaved the fuel pressure and took the number 4 injector out. put a cup under it and turned the key and a lot of gas came out quick so i dont think clogged.

installed the new injecor put it all back together and it still misses. i put my scanner on it and did the live data stream. it showed

fuel system 1 cl
fuel system 2 cl -fault ????
calc load percent 35.69
ect temp 165
stft b1 percnt 4.69
ltft b1 percent -19.53
stft b2 percent 14.06
stf b2 percent -19.53

You're correct, a valve that was stuck closed would cause the engine to make noise.

Since you had previously swapped injectors around according the post #1 above, I'm sorry that you purchased a new injector. The fact that the misfire remained on #4 even with the injectors, plugs, and COP should have been an indication that the injector is not the problem. At least now you know that the fuel rail is also not the problem and is providing plenty of fuel to the injectors.

Your long term fuel trims suggest rich mixtures on both banks over the long term (double check your numbers for bank 2 above), but the STFT on Bank 2 indicates the PCM is attempting to compensate for a really lean condition on Bank 2. The STFT for bank 1 though looks to be okay. Maybe the problem isn't cylinder #4 afterall....

During the datastream how were the oxygen sensor responding, both sensor 1 and sensor 2? Does your scan tool give you the option to monitor the cylinder misfires real time?

-Rod

scan tool isnt that good lol. i was looking and what the cl fault ment closed loop fault o2 up stream i switched the 2 up stream 02 sensors around thinking it would change the error to the other bank but it didnt help. it still showed miss fire cyl 4. iv about had it with cyl 4. when i looked at the 02 sensors they appeared to be factory. would the 02s cause the misfire like it is? sending the computer wrong signal there for sending ot much fuel to the injectors and causin misfire? that would explain the rich smell coming form the exaust.

stft b2 percent 4.06 typo

i thought about what you said the o2 sensors are just picking up on what the motor is telling it. the down stream 02s dont deal with the fuel managment do they? theres got to be another sensor making the bank 2 lean. my scanner only does freez frame data. it wont do the live data streaming.

i did a fuel pressure test and its about 30 or 40 maybe a little more.

Check the spark plug boss on cylinder 4 for water contamination, we have seen bad COP covers leaking water thus causing misfires.

The upstream O2 sensors gives a feedback signal to the ECU for Air/fuel mix, the engine is still missing on cylinder 4 (bank 1)!

Did you Reset + clear code, after COP replacement?
Was there a rust residue on the original COP's?

Tran
4 8
3 7
2 6
1 5
Fan

Bank1 = cylinders 1-4, and bank2 = cylinders 5-8.

What about the long term fuel trim numbers, are they really both the same (-19.53)? Also, please confirm the second -19.53 is LTFT rather than 'stf' that you have it labeled. If that's the case, this would suggest that long term the PCM has been trying to lean out the mixture on both banks quite significantly.

And you're correct, the purpose of the O2 sensor 2 is primarily to help the PCM determine the catalyst efficiency. Sensor 1 is one of the factors that will cause the PCM to alter air/fuel ratio. Unfortunately having a scan tool with datastream mode could really help you confirm if the oxygen sensors are doing what they should be doing.

It might be interesting as a short experiment to unplug the fuel injector for cylinder #4 and see if that makes the engine run noticeably worse and/or if it gets rid of the raw fuel smell in the exhaust.

-Rod

every time i do something to it i clear the codes before i strart it back up. new cop on cyl 4 plug is new neither one of the 2 had rust or any kind of traces of water. iv been reading about the bank 1 and stft and stuff at a idle my car is

stft b1 10.9
ltft b1 -18.7
stft b2 15.6
ltft b2 -18.7

at 2500 rmps
stft b1 1.56
ltft b1 -12.5
stft b2 14.6
ltft b2 -12.5

come to find out that typo wasnt really a typo it was 14. so the whole motor isnt breathing right. its not just 4 like rod said. thats just the only one the computer is reading. what causes such a varity of reading in my 02s

i have unplugged the cyl 4 injector and it didnt make any diffrence but i didnt put it on the scan tool though. sould i try doing that? i double checked all the numbers i wrote down at idle and 2500 and all those are right no typos there. and i did mean to put stft sorry bout that.

i just thought of soemthing also each time i clear the codes its deleting the freeze frames along with the long LTFT thats why the numbers are coming out the same in the stft and the ltft

If cylinder 4 is a consistant misfire, the ECU will throw a DTC P0304.
By disconnecting the fuel injector, or COP on cylinder 4 , your engine would sound the same.

but iv ruled out every cause i could think of in cyl 4 new injector plug and cop. the coil is firng fine. would just the cyl 4 cause the lean readings? im getting that code for cyl 4 misfire and im getting p0174 and p0172 which i could see from the stft and ltft. if sprayed the whole motor with carb clean thinkin it was a vacumm leak but the motor never reved up not even one bit. could egr or pcv valve cause this motor symptom? if so how would i go about checking them?

like rod said maybe it isnt even a misfire after all...

i have unplugged the cyl 4 injector and it didnt make any diffrence but i didnt put it on the scan tool though. sould i try doing that?

Okay, so that indicates that there really IS a misfire on cylinder #4 and it's not a phantom code, ie: you are focusing on the correct cylinder. We're trying to take baby steps here. As Danielsatur mentioned, you will expect to have a misfire code since you definitely forced a misfire. Also since the engine sounded the same it would suggest that it's a pretty constant misfire, not just an intermittent misfire. Did you notice, with the injector unplugged, if your rich smelling exhaust was gone? You may want to connect the scan tool again and clear the codes one more time just to be sure you're back to your baseline with everything reconnected.

While clearing the codes will reset the STFT and LTFT numbers, what you're reporting is not that they are the same. The STFT numbers are positive values (suggesting the PCM is increasing the injector pulse width) and the LTFT numbers are negative numbers (PCM decreasing the IPW). A few years ago I read a good article on diagnosing with fuel trim numbers, I think it was something put on the Internet by MOTOR magazine. This is a auto tech trade magazine, not one of the car enthusiast mags. You might try searching the Internet for it if you have time today. I seem to recall that it mentioned the critical part is the mathematical difference between the STFT and LTFT per bank. It also suggested typical manufacturer limits and I think your LTFT numbers are approaching those (between 15 and 25 typically). What's very intriguing to me is the B1 STFT at 2500 rpms. This would nearly suggest the misfire is not present, or not being registered by the O2 sensors, at 2500 rpms. How smooth was the engine at 2500 rpms? You don't want to get much higher in engine speed while in Park or Neutral though as the rev limiter will kick in and feel like a horrible misfire.

-Rod

If you miss one of the 4 strokes on cylinder 4, it will cause a misfire.
Intake, compression, combustion (power), and exhaust.

Test's:
Air Intake - Smoke test for unmetered air leaks
Compression - ok
Ignition - Fire ok
Exhaust - back pressure test on catalytic converter.

If the catalytic converter was plugged, fuel problems,MAF sensor, or unmetered air leaks on your intake, would cause random misfires on both banks.

How many miles are on your upstream O2 sensors?
Force a misfire, and a DTC!

how do i do a back presser test on the cat? and what is a smoke test. im thinkin the 02s are factory. they say ford on them. anything after 1800 to 2000 rpms the miss is gone. dont hesitate dont loss power runs great its just between idle and 1800 or so. i read that if you stft is low or high and you take it to 2500 and they almost return to normal chances are you have a vacumm leak. were else could there be a vacum leak whats the eblow under the intake that brakes or cracks called?

Smoke Test video, see www.youtube.com/watch?v=FfiQ7qWiG-M (http://www.youtube.com/watch?v=FfiQ7qWiG-M)
Catalytic converter test, www.youtube.com/watch?v=IzyvL5tQLzU (http://www.youtube.com/watch?v=IzyvL5tQLzU) , any local muffler shop will check for free.

If the miss is during idle only, check the PCV/ Air supply line, and port on the valve cover, it gets plugged with PCV gunk.
The air tube on the bank 1 valve cover going to the throttle body, it supplys air for the engine during the closed throttle body condition (Idle).

Because of Age/mileage consider getting two H02 sensors for the upstream cat's only.

just put two new upstream o2s on it just to make sure it wasnt them and it wasnt. still missing. but i can mark off bad o2s as a problem now. the driver side cat looks as if its been replaced.... it looks newer then the one on the passenger side. would this make a diffrence?

on the v8 models were is the pcv valve? is it the same place as the v6 models? if so is it easy to check? :headshake im just waiting to put a new part on clear the codes and start the car and it idle perfect... is there a such thing a perfect on a ls hahahaha

Keep the old HO2 sensors for spare down stream replacements.

Have a back pressure test done free @ the local muffler shop, so we can rule that out too!

Also find a shop, that can perform a smoke test only.

There is a separate converter for each bank, so once plugged converter would not cause a misfire on both banks. It might cause a lack of power, but wouldn't explain a misfire that remains on a single cylinder or explain why forcing a misfire on #4 would not make a difference in the way the engine idled. Restrictions in the exhaust would typically be more apparent under higher load and not so much at lower rpm, opposite of what you're experiencing.

The V8 does not have a PCV valve or the PCV elbow that is a common issue on the V6, so don't waste time looking for that.

The EGR valve should be closed at idle and begin to open as the engine goes off idle. If it's not completely closing at idle that would be a vacuum leak, but again that would not explain the cylinder #4 misfire or results when forcing the misfire.

-Rod

just got back from the muffler shop they said the cats were fine. iv called a few places around here and they dont to the smoke test.... if the plug going to the connector was bad the coil wouldnt even be firing would it? at a idle the stft are off but under a load of under rpms they almost go back to normal.... iv read a few things that say a vacum leak would cause this. but i can not find one. would acam sesor going out maybe cause this?

Need to find a shop todo a smoke test, need to rule out unmetered air leaks, see
forum search ''P0171''

Compression Test - OK
Catalytic converter Test - OK

i found a shop that will do it for 67 dollars im gonna try to get it done tomorrow as i cant think of any way of making a smoke tester my self. i thought about a fog machine but i see that going really bad really quick. :runaround:

hopefully i have a guy coming later today with a nice scanner that will tell me more. could it be that the computer is telling injector 4 to stay open? and during an idle its pooling up in the cyl 4 causing a misfire but under a load its able to process all that fuel at one time causing the car to run rich?

what sould i look for when he scans it?

RedNeck smoke Test -
1) Remove Air filter

2) Wrap plastic around the air filter, and plug filter back in Air filter Box.

3) Remove Brake booster vacuum hose.

4) Light a Black & Mild cigar, blow smoke into the brake booster vacuum hose, and plug hose between drags.

5) Watch for smoke leaks.

LOL- Maybe we can use pot !
+ K9 police dog to find leaks.
$65 isn't bad, because the Machine is $1500 + Tech per hr.

:rofl:

thats just up my alley hahaha
i think ill just take it to the shop tomorrow. i hope it something like the computer is messed up or a vacuum leak i cant find.

im just hoping everything in the motor is fine and isnt hurt. if something was messed up in it surely id be getting more codes.

by the time somebody filled up the vacuum system with pot smoke, the person doing it wouldnt know what there even blowing into it for. :evillol:

just put it on one of the nice scanners and they didnt see anything. when i unplug number 3 cyl the miss doesnt get worse or better. they guys here seem to think that bank 1 jumped time. they said one of there ls that came in did the samething but wasnt off enough to throw any codes.....

this sound believeable.

still gonna try to go tomorro and get smoke test done.

I am having some similar problems on my brothers 2004 V8 LS. I was thinking vacuum leak to, have a lean condition on bank 1 on my bros car. Just read a TSB for LS 2000-2004. A good way to check for vacuum leaks is to record the STFT and LTFL for both banks at idle and 2500 RPM, then you add the number for bank 1 and bank 2, take yours for example:
stft b1 10.9
ltft b1 -18.7
stft b2 15.6
ltft b2 -18.7

at 2500 rmps
stft b1 1.56
ltft b1 -12.5
stft b2 14.6
ltft b2 -12.5

So STFT B1 + LTFT B1=-7.8 for bank one at idle, do this for each bank at idle and 2500 RPM. The numbers are
IDLE:
B1 -7.8
B2 -3.1
2500 RPM
B1 -10.94
B2 2.1.
Now the difference between B1 idle and B1 2500 RPM should be less then 15, if its greater then 15 then you probably have a vacuum leak. Looking at your numbers you are much less then 15 so probably no vacuum leak-according to this TSB from Ford.

thats some good information to know. what did you ever firgure out about the car your working on? im gonna go in the morning to get that smoke test done. all iv been doing is working on this car the past few days. :runaround:

i had a machenic look at it and hes just as stumped as i am. all he could come up with his snap on scanner was get the computer flashed or a vacum leak. thats what his scanner showed.

if the smoke test comes back negative for no leaks i guess next step it to look into a new motor. id rather by a motor then put timing chains and crap in one. my 2002 sport trac timing chain broke in it one day and i priced a new timing chains and gaskets and stuff by the time i did all that it was cheaper to buy a motor with a warante then try to fix it.

there 32 valve motors with 4 cams. if one cam jumped a tooth of or something wouldnt it throw a code?

Focus on Test's 1st , befor throwing parts + service.
Compression - OK
Catalytic converter - OK
Vacuum Smoke test?
Fuel pressure test low/high?
Battery/Alternator Load test ?
HO2 sensors - New
MAF?

If timing was off, the compression test wouldn't be good.

$3.5K was spent on a bad fuel filter, see LS-nightmare www.lincolnforums.com/forums/index.php?showtopic=5675 (http://www.lincolnforums.com/forums/index.php?showtopic=5675) , Low pressure fuel problem.
? $ , because of a bad fuel pump, see Car dies out www.automotiveforums.com/vbulletin/showthread.php?t=975424 (http://www.automotiveforums.com/vbulletin/showthread.php?t=975424) ,high fuel pressure problem.

30psi of fuel presser running im keeping the fuel pressure gauge attached to the car i check it after i drive it and before i drive it to make sure theres no change. after i get the smoke test dont im going to get a temp gauge that looks like a gun that reads temps with a laser. im going to point it at each part of the manafold that bolts to the head. im going to get every temp from each cyl. maybe a temp reading will tell me more about what is happening on each bank.

Still working on mine as well to figure out the problem. My fuel PSI is running around 55, that's according to the scan tool at Orielys, stays the same at 2500 RPM. I have also done my own back PSI test on the cats-good. My bank 2 is giving the rich code and bank 1 lean, I shot the exhaust with an ifared gun, bank 2 the rich bank is running much cooler then bank 1, also when I pulled the plugs on mine I could tell bank ones really lean-plugs white. One problem on mine is that I can disconnect all the coils or injectors on bank 2 and the car doesent seem to miss any worse, but do just one cylider on bank 1 and each one you disconnect it gets worse, dissconect all of bank 1 and it wont hardly run. Is your car doing any thing like that? Let me know what your exhaust temps are doing. I also swapped all the coils from bank 1 to bank 2 to rule those out. Replaced fuel filter and plugs, replaced both 1 O2 sensors on bank 1 & 2. Taken voltage readings to confirm that all coils/injectors are receiving 12 v DC on one of the two wire going to them-did this with kOEO. Also checked them while running to make sure other wire was giving it signal to operate, just made a very voltage fluctuation but was the same for all coils and injectors. I was debating having a smoke test done as well because I cant find a leak. I am just about at my wits end with this car too. If I do a smoke test and it doesent show any leaks then I figure its got to some thing with the PCM.
P.S. You can view your cam timing with a live data stream tool, at least on the 04, I have a varible intake cam which can make it even more of a problem but my cam timing looked good on the scan tool.

man sounds like mines doing the exact same. i havnt looked at the temps yet. my bank 1 is the one acting funny. i talked to a guy that said he worked on a ls and he said it jumped time. it run fine after a certain rmps. but im going to get all the test done first just to rule everything else out if your getting 50 im only getting 30???? i wonder if i sould get a fuel pump

the more i think about it if the timing was off like the other guy said the compression wuldnt be no were near as good as it was. im going monday at 8 am to get the smoke test done. thats the earliest i can get in. do you still drive your ls every day?

No its not being driven right now, its in my shop, think I am going to look at a smoke test as well just to see. Mine runs rough at idle and starts to smooth out around 1500-1800 RPM. When driving if you step on it about 4 grand I can here some chatter from the engine, not sure if its valves or from it misfiring. I have gotten random misfire codes and misfires on 5, 7, and 8 cylinders as well. But like I said I can disconnect the whole bank 2 and it doesn't run any different. But the car still has plenty power and take's off like a bat out of hell. I have pulled my EGR and cleaned it, disconnect the vacuum line at idle and plugged it to make sure the EGR solenoid isn't keeping it open-all good with that. My fuel PSI was 55 according to what the engine is reading-if that's accurate, no schrader valve on mine to hook up to, I need an additional tool from Rotunda to read fuel PSI with a gauge, not sure how that unit would hook up though. I just bought a scan tool that hooks up to my laptop, should give me alot more info but wont be in till next week, should be able to do a few more tests with that. Will let you know if I find anything.

According to the tech manual for your car your fuel PSI should be 35-65, mine says 35-70. Also your flow rate should be 21 lb./hr, they don't give a flow rate for mine. It also give a resistance of 8.5-15.5 ohms, I am guessing that's for the injectors-the charts not real clear on that part.

Compression Test - OK
Catalytic Exhaust - OK
Fuel Test - OK
HO2 sensors - OK
Unmetered Air leaks?
MAF?
Load Test on Batt & Alternator?

If you can't get a smoke test done until Monday, have a free Load test done on your Battery + Alternator.

Because of age, mileage, wear + tear, consider a new MAF sensor.

Did you clean the air port, and air tube on bank 1 valve cover going to the throttle body?

i just ordered a new maf it wont be here till tomorro. iv been ordering parts and putting them on and if they dont fix it i take it back off and get my money back hahahaha...

i kept the 02s though and the coils. i hope one of us figures out something soon.

Good! ,lets do a good Throttle body + IAC cleaning too.

Lick a tick on a dog, you will get it.

i bought a new egr valve to im only gettin 10 mpg tops highway!!!!

Man I know the pain you are going through with your lincoln ls... Heres the bad thing with mine but its also a good thing too. I bought everything for that car brand new parts spent $ after $ after $ gaaaa. Mine was doing the opposite of what yours is doing mine was running fine at idle but under load it would damn near shut off or even shut off. Well after buying new parts and scratching my head and getting greasy which didnt mind, my last option was F*** it take it to a shop. Took it to a shop and running fine then stalls losing fuel pressure. Fuel pressure dropped to 13lbs. Come to find out it was the fuel pump which I thought was new. Well it was it was the Jet Fuel Pump that was going out. Hopefully you will get your LS back to normal. I know one thing these cars are not cheap by any means. Good Luck on finding that problem. Hopefully you will find it soon. I asked the guy that fixed mine about yours he says it sounds like a vacuum leak to him. I dunno. Good Luck

altnator and battery tested good. ordered a new iac yesterday egr didnt fix it i took it back hahahha

what about a fuel pressure reglator?

mas air flow sould be here today i gotta go check it out. how many cam sensors are in this motor? it having 4 diffrent cams are there 4 diffrent ones?

just wondering

im not going to give up on this thing untill i fix it damn it.

There's no fuel PSI regulator on mine, so you might not have one as well, pump just comes on and off to keep psi in range. Should be one cam sensor per bank. When you had a scan tool hooked up with live data could you see the MAF sensor increasing in air flow as you revved the engine up? If so then it is probably still ok.

true.... why would i be getting such bad gas milage? what controls how much fuel the cyls get? i know the computer controls the injectors. but what ever is messing up is telling the computer to send to much fuel to the motor.

coolant temptaure sensor??

mass air flow didnt work didnt change it a bit.

Compression Test - OK
Catalytic exhaust test - OK
Fuel pressure test - OK
HO2 sensors - OK
Load Test Batt/Alt - OK
MAF - OK
Unmetered Air smoke test - pending
A smoke test would pin point a bad Egr, or gasket.
Let's look & log all problems-
Misfires on bank 1, cylinders 2 + 4
P0171
Poor fuel economy

Get this car to throw some more DTC's!

Reset + Clear codes
Take her out on the highway, and push some horses.

thats a good idea.... ill take it out on the high way and get on it. hell i drive it like a race car now :naughty:

ill drive it atleast 20 mins at highway speeds and see if she throws any more dtcs.