Lumina Dies randomly... weird problem

My 91 Lumina Euro 3.1 dies randomly.. its scaring me, i have been driving my 73 Chevy Cheyenne C20 Camper special ;) (with a 454 Big block 4:6:3 gears 12 bolt posi) and the truck is nice and all... but i would like to get more than 7 miles per gallon....

Now the lumina does not have any codes, always checked fluids, refilled when needed, all those kinds of things. timing belt was replaced at 120k miles, car now has 144k, and its not the transmission my car has the TH-125 (3 speed no overdrive) Now for what its doing.

The car randomly dies when warmed up, or at least i think only when warmed up. Once she starts dieing, she will keep doing it if you start her back up. When she dies you can feel a rpm surge sometimes and then she just dies, othertimes i dont notice it like if im in park its a nice and quiet car.

When she dies you can turn the key and start her right back up, and she runs like normal. It died on me a few times, one time i was getting on the freeway on one of those loops that go from an overpass to get to the freeway which is going another direction. she died about halfway through since there was no throttle input.

the other time i was just sitting in the parking lot at 7-11 waiting for my friend to get out of the store, and i went to shift and pressed the gas and she was dead. started right back up though.

the third time i was driving back from a few cities over, i was doing 65 MPH and 3000 RPM all of a sudden i feel a big grab, like something locked up in the tires and i look down at the Tach and wathced the needle bounce fro 3000 right down to about 700 or so and right back up to 3000 and stopped, the car kept driving like normal. so i gave her some more gas sped up to about 80ish since if shes going to be doing this i want to be home or at least closer to it. i felt her give me another one but smaller, so i was about 20 exits from my place, about 5 miles. i let off the gas a little, and the entire way back i can feel these little rpm drops and hear them too, but it was random.

now i went around and checked all the fuses, they are fine. Altenator is new within a year its fine, battery is fine, car could use some new spark plug wires and plugs but that cant cause this, its not ignition related im sure of that.

My grandfather is a GM tech, he was thinking that it could be electrical if it happened that fast. My brother tells me he think its a Vacuum leak, and my neighbor who is a GM tech said it could be a Fuel pump. But if it was a fuel pump could it still make it run fine untill it warmed up?

Im leaning towards a Vacuum line, can anyone give me any insight on this. i really want to get her fixed by this weekend.

Thanks
-Jeff

yes, question for you? 3.1V6? or 3.4 DOHC V6? The 3.1's all come with timing chains I believe, and the 3.4's came with belts. It doesnt matter, but you said euro, so I was kinda wondering if that 3.1 was a typo. Ok, next, Dont rule out the spark plugs and wires. Actually, as I was reading your problem, I immediatly thought the plug wires may be arching over to something when they get warm. Do yourself a favor and if the plugs and wires look bad, chances are they are, and spend a little time and money and replace them. It may solve your problem. If nothing else, give you better gas milage and rule out plugs and wires as the problem. AS for a fuel pump. They are usually either completly good and working, or completly bad, not many cases of in between. You can hook it up to a fuel pressure guage and see if there is enogh pressure there. I think around 40psi is the spec. Not sure. Could also be a sticky injector, have you tried fuel injector cleaner lately? Get some that wont harm an o2 sensor, I was using some one time, and my o2 sensor took a crap. Good luck.

I can't see this gripe ending up to be just a vaccum leak. As a vaccum leak would be the most likely cause of a high idle, and not a engine stall. I just did a search for "fuel pressure" ( http://www.automotiveforums.com/vbulletin/search.php?searchid=1182853 (http://www.automotiveforums.com/vbulletin/search.php?searchid=1182853) ) and found some usefull information. Check it out

How old is the fuel filter, test the fuel pressure to get a general idea if the pump is getting weak.

Yea Tblake, its the 3.1 The Euro edition just had the same Suspension package as the Z34, but with 15 in rimcs instead of the 16. they look exactly the same though.

One thing also, thre old owner of the car was my neighbor and at 120k miles it had a major tuneup done, she said shes not sure if the PCV ever got replaced. and im wondering if that can do it also? maybe cause some kind of weird thing. i know that it can cause high idle if clogged. but i will check into getting wires, and maybe even some new plugs. I just hate doing the rear plugs and wires... just gotta rock that engine forward for an extra 4 inches hahaha.

the Fuel pressure is fine, it was like 40 psi i think my brother said. im not sure

me too, same problem, will apreiciate any imput!
dies randomly

A vacuum leak is overcome as soon as the throttle plate is open, so if it dies under any throttle, it's most likely not a vacuum leak.

Why do you say it's not ignition? That sounds most likely, like an intermittant loss of crank sensor signal or module control.

Usually (but not always) an iffy fuel pump will lay down on acceleration, then refuse to start for a while till it cools a little. Might be worse the lower the tank is on gas.

I'd start by putting a fuel filter on, regardless of how old or new the current one is. Then I'd check the battery terminals and any other primary power junctions I could get to easy. Then have a look at the CPS and module connections/wiring.

See if that turns up anything.

Even if the sensor is losing signal. wouldnt that throw out a code? hmm well im going to replace the PCV since its $2.99 at autozone lol. then im going to look at the prices on a CPS, and i have been wondering if the ECM could be going bad, or have a bug in the PCM. i mean she high idles but only by a couple hundred RPM, doesnt always start up right, wont go up to 2k RPM and drop down like she used to, she might go to 1500 and just sit there for a sec and drop to 1200 - 1300 and just start trying to idle there. after about 10 mins or so she goes a little more down. i dunno im tired of driving the truck and i miss my lumina... im attached to my baby :D

thats the other thing Jeffco, if im sitting there waiting for her to die, and i see the RPM flux and gas it she wont die. she has never died on me with throttle input. the freeway thing was the only time she did anything with throttle input

thats the other thing Jeffco, if im sitting there waiting for her to die, and i see the RPM flux and gas it she wont die. she has never died on me with throttle input. the freeway thing was the only time she did anything with throttle input

Oh, OK. That makes more sense. It could be a vacuum leak then. EGR and IAC would be likely suspects.

If it died when you lifted off the throttle that time on the freeway, that would put that episode in the same area of suspicion.

The PCV is a good idea. I've never bought one for my own car, I always just flush them with carb cleaner and put it back in.

is it possible that maybe the EGR or IAC is going bad and at some point allowing an electrical current through the engine. or shutting down the current? i know Vacuum leaks can do odd things. but my grandfather who was a GM tech for 30+ years says it sounds electrical. im not sure but a lot of things make sense lol

your ECM is under the hood on your car, and since it's 15 model years old, I'd check the wiring harness to the ECM. IT is located under the radiator overflow bottle on the passenger side. While your in there, check the bottom side of the underhood relay center for possible corrosion. This of course is assuming that you have had the ignition module checked and you've replaced the crank sensor. The crank sensor comes out with one bolt and costs about $15. Change it, that eliminates it from the equation.

Picked up a $20 CPS and a $2.99 PCV total was 24.99 exact after tax lol. so im going to throw those in, and i checked the relay center no sign of corrosion same with ECM the wiring looks fine.

im going to talk with my grandpa about checking the Ignition module checked

Earlier i had my car in park after taking her for a drive, and she died when i tried to shift her in reverse because i wanted to go to the gas station.

She only dies and acts up if she is warmed up, otherwise she is fine. so im going to keep driving her for short trips and nothing more. and my first Gear if i throw it down into 1st on the Steering Colum makes a loud high pitched whine.. is that bad? in drive its fine but yea lol any ideas on that one?

okay took the ECM to autozone to figure out that they dont test them... well w/e they can go screw themselves for now :D i slapped it back into my car, relearned idle and the car seemed to run fine. so i took her for a longer ride where she could get warmed up nicely. on the way back home i felt a grab 2 times 1 a few seconds after the other, but didnt see the RPMs jump. im wondering, could this be the TCC? i know i can just disconnect that jumper and see if she still does it. and if not then im good. My only concern is that i dont have any SES codes comming up at all. and im hoping that if i dont drive her and it is the TCC that i can repair it myself without having to worry about much.

I have the same problem. Did you find the problem? We have checked and replaced the following

plugs/wires/fuel filter, air filter, throttal positioning sensor, crank sensor, and computer module. After every attempt problem reappeared when auto hot.

I found what I "think" is a vaccumn hose. The shape of it looks like it goes into the "throttal body" somewhere but I haven't found the connection yet.

replace your Ignition control module, that is what i am told is wrong with mine. they are about $152 new at autozone (bay area C) and like a $15 gasket, if you have replaced the comp and that has not done it replace the ICM. mine is being done on monday by my brother at his GMC/pontiac dealership he works at. we used a tech1 scan tool and it wasnt the comp. and the ICM was acting odd... and i was told by a couple mechanics that usually the ICM is going bad but people think its the computer.

okay took the ECM to autozone to figure out that they dont test them... well w/e they can go screw themselves for now :D i slapped it back into my car, relearned idle and the car seemed to run fine. so i took her for a longer ride where she could get warmed up nicely. on the way back home i felt a grab 2 times 1 a few seconds after the other, but didnt see the RPMs jump. im wondering, could this be the TCC? i know i can just disconnect that jumper and see if she still does it. and if not then im good. My only concern is that i dont have any SES codes comming up at all. and im hoping that if i dont drive her and it is the TCC that i can repair it myself without having to worry about much.

i had and could be still having injector problems
i was crusing on the inter state
nd going about 45 mph
then opened it up to aroud 85
then was decellerating again then the car fell flat on its face
and won't idle at all
and i could only go about ten mph
i found one bad injector but replaced then all
ran good for about a month now having similar problems again sounds like yours \
mine seems worse when is warned up
it also idles alittle rough
not nice and smooth like when injectors where first replaced

maybe have the injectors checked or cleaned

every oil change i use injector cleaner, and i checked them they all ran fine with the right voltage. yours sounds much diffrent then mine, when my car did its little thing on the freeway it just dropped a lot of rpms like there was no spark so no engine and then jumped right back up. we have got it down to being the ICM and i am having it replaced today or tomorrow whenever i get the time and my car back from my bro.

Okay my car is now fixed and working perfectly.

I replaced the ICM (Ignition Control Module) It cost me $99 at Autozone. Lifetime warranty and made by wells. Car runs like a champ. no more problems i hope :D and more work is picking up with my 2nd job now and im going to start doing my interior work on her.

i started working on her this morning at 7:00 in the freezing cold with no jacket.. my head was steaming hahaha. i finished at 11:00 My Lumina ate my 7/32 Socket and extension 1 time, i recovered it after about 20 mins.... and then it ate my 7/32 socket... i couldnt get that one out, i had another so it didnt matter at the time. getting the coils and stuff back in place was a pain in the butt. but i found if u shove it all the way up left, it kind of sits in place and just screw in the far right coil and life is easier.

This is an experience i would rather not do again, although my car was dead cold... was very stressful at times. i still have yet to find that missing socket in my car :D and im driving it! hahahaha. it will eventually fall out. I know it went behind the starter and down into the cradle somewhere, or i think it did. im not worried. my car has eaten my tools before. once it was a Socket wrench that took some time and work to get back.. now i promised her if she worked good i would clean her :D time to wash and 2x coat wax my baby.

She really is the devil in a red dress : / :cwm27:

Okay my car is now fixed and working perfectly.

I replaced the ICM (Ignition Control Module) It cost me $99 at Autozone. Lifetime warranty and made by wells. Car runs like a champ. no more problems i hope :D and more work is picking up with my 2nd job now and im going to start doing my interior work on her.

i started working on her this morning at 7:00 in the freezing cold with no jacket.. my head was steaming hahaha. i finished at 11:00 My Lumina ate my 7/32 Socket and extension 1 time, i recovered it after about 20 mins.... and then it ate my 7/32 socket... i couldnt get that one out, i had another so it didnt matter at the time. getting the coils and stuff back in place was a pain in the butt. but i found if u shove it all the way up left, it kind of sits in place and just screw in the far right coil and life is easier.

This is an experience i would rather not do again, although my car was dead cold... was very stressful at times. i still have yet to find that missing socket in my car :D and im driving it! hahahaha. it will eventually fall out. I know it went behind the starter and down into the cradle somewhere, or i think it did. im not worried. my car has eaten my tools before. once it was a Socket wrench that took some time and work to get back.. now i promised her if she worked good i would clean her :D time to wash and 2x coat wax my baby.

She really is the devil in a red dress : / :cwm27:

...Please forgive my ignorance (American cars seem "Foreign" to me [:D]), but is the ICM the same as the ignition coil? Instead of the standard "distributor" which is fed by a seperate coil, this car has a harness that plugs directly in there (I'm assuming the coil module is inside?).

Your symptoms/solutions also sound similar to my reply on this thread: (http://www.automotiveforums.com/vbulletin/showthread.php?t=268400)

...Please forgive my ignorance (American cars seem "Foreign" to me [:D]), but is the ICM the same as the ignition coil? Instead of the standard "distributor" which is fed by a seperate coil, this car has a harness that plugs directly in there (I'm assuming the coil module is inside?).

Your symptoms/solutions also sound similar to my reply on this thread: (http://www.automotiveforums.com/vbulletin/showthread.php?t=268400)





Okay, your best bet. if you have a day off, and another ride to autozone go ahead and pull your Ignition control Module, the coils sit on top of it. take it to autozone and they can test it. just make sure you have your car nice and cold when you do this. the coils are in the front of the car above the front exhaust manifold. you will have to take the bolts out kinda blindly but it can be done.

When putting the ICM back in place, shove it all the way up left, and it will kind of find its little groove to sit in. you will feel it once you hit it. then slap on teh far right coil, bottom bolt first and start screwing them all in.

Okay, your best bet. if you have a day off, and another ride to autozone go ahead and pull your Ignition control Module, the coils sit on top of it. take it to autozone and they can test it. just make sure you have your car nice and cold when you do this. the coils are in the front of the car above the front exhaust manifold. you will have to take the bolts out kinda blindly but it can be done.

When putting the ICM back in place, shove it all the way up left, and it will kind of find its little groove to sit in. you will feel it once you hit it. then slap on teh far right coil, bottom bolt first and start screwing them all in.

UPDATE: I did what you told me... in fact, I just picked up 3 new coils from Autozone and swapped them out. I did the factory recommended specs and tested the coils w/ the multimeter (iirc the specs are 0.5-0.9vdc), and they showed to be "bad". The wires were also replaced as well. The minute I put them in, I tried cranking... the engine turned over and fired up immediately. Repeated it couple of times all with good results.

HOWEVER, the idle would still be very jerky.. with RPM's flutuating up and down. I tried giving it some gas... the RPM's when then drop the instant I tap it, then climb up...and immediately drop to a point of stalling (it stalled a few times). I tried resetting the ECU to let the ECU re-learn... no luck. This time I opened up the air box, removed the MAF, and cleaned the TB and maf w/ intake/carb cleaner and everything else... and a lot of gunk came out. I tried starting the motor again...same results... I let the car idle to burn off all the junk. It idles for about 5min or so. I then tried giving it gas again after... and the second I even tap the gas, engine splutters then stalls. Keep in mind, the whole time the engine has been running super rich... as if the combustion chamber has been flooded.

I did some more searches, and found these other possible causes:

EGR
IAT (I believe this car has one?)
ECT (coolant temp sensor)

Does anybody have a diagram of these components (location, procedures, etc)...or can suggest anything else?

Thanks again

-Jeff

UPDATE: I did what you told me... in fact, I just picked up 3 new coils from Autozone and swapped them out. I did the factory recommended specs and tested the coils w/ the multimeter (iirc the specs are 0.5-0.9vdc), and they showed to be "bad". The wires were also replaced as well. The minute I put them in, I tried cranking... the engine turned over and fired up immediately. Repeated it couple of times all with good results.

HOWEVER, the idle would still be very jerky.. with RPM's flutuating up and down. I tried giving it some gas... the RPM's when then drop the instant I tap it, then climb up...and immediately drop to a point of stalling (it stalled a few times). I tried resetting the ECU to let the ECU re-learn... no luck. This time I opened up the air box, removed the MAF, and cleaned the TB and maf w/ intake/carb cleaner and everything else... and a lot of gunk came out. I tried starting the motor again...same results... I let the car idle to burn off all the junk. It idles for about 5min or so. I then tried giving it gas again after... and the second I even tap the gas, engine splutters then stalls. Keep in mind, the whole time the engine has been running super rich... as if the combustion chamber has been flooded.

I did some more searches, and found these other possible causes:

EGR
IAT (I believe this car has one?)
ECT (coolant temp sensor)

Does anybody have a diagram of these components (location, procedures, etc)...or can suggest anything else?

Thanks again

-Jeff


i had similar problems with my 91 w/3.1
i was running extremely rich
after pounding my head agianst a wall for a couple of days
checking different things
i finally took off the upper intake manifold
and checked the injectors
with an ohm meter
i found one realy bad one and a few others
were on the low side of being good
the realy bad one masured only 4 ohms
others were from 11.6 to 12.5
they all should be around 12 ohms
i replaced them all with reconditioned ones
since i couldn't aford new
and car runs well now
idles drive ect.
maybe look there

i had similar problems with my 91 w/3.1
i was running extremely rich
after pounding my head agianst a wall for a couple of days
checking different things
i finally took off the upper intake manifold
and checked the injectors
with an ohm meter
i found one realy bad one and a few others
were on the low side of being good
the realy bad one masured only 4 ohms
others were from 11.6 to 12.5
they all should be around 12 ohms
i replaced them all with reconditioned ones
since i couldn't aford new
and car runs well now
idles drive ect.
maybe look there

Did you check your IAC and EGR and clean them out?..or did you replace the injectors immediately?

Did you check your IAC and EGR and clean them out?..or did you replace the injectors immediately?

i had replaced iac
a while ago
so i new it was good
the egr will cause a code if it is bad
(one of its componets not working or if it is stuck)
if an egr is stuck open will cause a lean fuel mix
and through a code

if you have the time check your injectors
i would deffinitly check them before buying new ones
new one are like $65 each (at autozone)
i found reconditioned at injectors4u.com for $16 each

but i am not an expert
just sounds similar to my problem

iac will only affect idle

i had replaced iac
a while ago
so i new it was good
the egr will cause a code if it is bad
(one of its componets not working or if it is stuck)
if an egr is stuck open will cause a lean fuel mix
and through a code

if you have the time check your injectors
i would deffinitly check them before buying new ones
new one are like $65 each (at autozone)
i found reconditioned at injectors4u.com for $16 each

but i am not an expert
just sounds similar to my problem

iac will only affect idle

My problem is all idle related. With the coils and wires now replaced...the car would start up immediately. HOWEVER, the idle would be very jerky (with a scent of unburned carbon/fuel). I will have to rev the car up a few times for the idle to settle, but sometimes it doesn't settle...and instead..the RPM's would drop even lower and sometimes stall the car.

Forgive my ignorance, but where exactly is the IAC located at? Any diagrams/pics would be appreciated. I figured the car has 115k, and I dont think the IAC was ever cleaned or replaced.

Also..any thoughts about replacing the fuel filter that could probably be another remedy?

-Jeff

My problem is all idle related. With the coils and wires now replaced...the car would start up immediately. HOWEVER, the idle would be very jerky (with a scent of unburned carbon/fuel). I will have to rev the car up a few times for the idle to settle, but sometimes it doesn't settle...and instead..the RPM's would drop even lower and sometimes stall the car.

Forgive my ignorance, but where exactly is the IAC located at? Any diagrams/pics would be appreciated. I figured the car has 115k, and I dont think the IAC was ever cleaned or replaced.

Also..any thoughts about replacing the fuel filter that could probably be another remedy?

-Jeff


iac is in the throtle body
it is black with two torx screws
holding it in place
it has like 4 or 5 wires
going to it
it is sort of round with a oval flange that the bolt go thru

i think this too would give you a code but
it is worth looking at
is your check engine light on?
the car runs fine off idle?

if your check engine light is on autozone can read your codes
for free and they may even help you locate the sensor

or the have these key things you can buy for like a dollar or two
that you can plug into the aldl connector
to get the codes your self
and i would buy a haynes manual ($15-$20)
it tells you and shows you a pretty good descripition of
the idle air controler

iac is in the throtle body
it is black with two torx screws
holding it in place
it has like 4 or 5 wires
going to it
it is sort of round with a oval flange that the bolt go thru

i think this too would give you a code but
it is worth looking at
is your check engine light on?
the car runs fine off idle?

if your check engine light is on autozone can read your codes
for free and they may even help you locate the sensor

or the have these key things you can buy for like a dollar or two
that you can plug into the aldl connector
to get the codes your self
and i would buy a haynes manual ($15-$20)
it tells you and shows you a pretty good descripition of
the idle air controler

Just picked up a scan tool lastnight. Scanned the car for codes, and it gave me missfire codes. Missfires in Cylinder #6, and "Random Missfires". My plugs are only a week old, but they are completely FOULED and scorched black with carbon (richness). I didn't get any other codes other than "Evap/Emissions", which could be due to it running rich and missing.

A faulty IAC or EGR would have thrown a code i suposse? I've had a few people (including yourself now) telling me it's the injectors, and I will have them tested tonight and let you guys know the results. If it IS the injectors, it could possibly be #6 (most people are complaining about that one), and that's the same cylinder giving me the missfires.

Thanks again

Jeff

Just picked up a scan tool lastnight. Scanned the car for codes, and it gave me missfire codes. Missfires in Cylinder #6, and "Random Missfires". My plugs are only a week old, but they are completely FOULED and scorched black with carbon (richness). I didn't get any other codes other than "Evap/Emissions", which could be due to it running rich and missing.

A faulty IAC or EGR would have thrown a code i suposse? I've had a few people (including yourself now) telling me it's the injectors, and I will have them tested tonight and let you guys know the results. If it IS the injectors, it could possibly be #6 (most people are complaining about that one), and that's the same cylinder giving me the missfires.

Thanks again

Jeff


just make sure you check them before you buy them
you also may want to get a noid light
it is a test light that plugs into the injectors electrical connector
to check for a pulse from the computer you may have to do this with the manifold off
so i would disable your ignition by pulling the dis fuse
to prevent the car from starting
plug in the noid light and crank the engine
you may need an assitant
to look at the light or crank the engine
also look at your wiring for the injectors
make sure none of them are worn thru and shorting out
this could cause your injectors to not work
but it if there was a short it would or should blow the injector fuse

good luck

Just picked up a scan tool lastnight. Scanned the car for codes, and it gave me missfire codes. Missfires in Cylinder #6, and "Random Missfires". My plugs are only a week old, but they are completely FOULED and scorched black with carbon (richness). I didn't get any other codes other than "Evap/Emissions", which could be due to it running rich and missing.

A faulty IAC or EGR would have thrown a code i suposse? I've had a few people (including yourself now) telling me it's the injectors, and I will have them tested tonight and let you guys know the results. If it IS the injectors, it could possibly be #6 (most people are complaining about that one), and that's the same cylinder giving me the missfires.

Thanks again

Jeff


i have also been told to replace all
because one going bad is a sign that all are getting
week
or what ever
i don't know for sure if you should but it would save you time
in the long run
if another one fails in the future

if you have 3 wires on your oil sending unit short out the 2 across from each other. at the plug with a paper clip. fuel pump won't come on if the oil pressure is low.

Problem was fixed.

Cause: Fuel Pressure Regulator ;) Pulled the vacuum hose off the FPR during idle, and massive amount of fuel squirted out of the valve, indicating a torn diaphram which is keeping the fuel pressure from being lower during idle (which explains why the car idled badly and fouled plugs, but ran normally at WOT). Cost me $70 at AutoZone, and took 30min to replace.

Future Note: Check the FPR by pulling the vacuum, to check for any fuel leaks. Fuel should NOT make it's way out to the vacuum, nor should you smell any unburned fuel from the line. Any signs of fuel in the vacuum is an indication of a FPR going bad, which will throw all the "Missfire codes", which is NOT caused by bad coils, wires, or plugs, but by the combustion chamber flooding itself. :)

Problem was fixed.

Cause: Fuel Pressure Regulator ;) Pulled the vacuum hose off the FPR during idle, and massive amount of fuel squirted out of the valve, indicating a torn diaphram which is keeping the fuel pressure from being lower during idle (which explains why the car idled badly and fouled plugs, but ran normally at WOT). Cost me $70 at AutoZone, and took 30min to replace.

Future Note: Check the FPR by pulling the vacuum, to check for any fuel leaks. Fuel should NOT make it's way out to the vacuum, nor should you smell any unburned fuel from the line. Any signs of fuel in the vacuum is an indication of a FPR going bad, which will throw all the "Missfire codes", which is NOT caused by bad coils, wires, or plugs, but by the combustion chamber flooding itself. :)


good diagnossis
but don't say that the coils can't cause a miss fire code
a combination or problems can cause one code
or one problem u don't even think could cause the problem
the computer isn't smart
it only knows if some thing is wrong
so if its miss firing it will only know its missing
and not exactly way it is

i didn't have any codes telling me my injectors were bad
i didn't even have a miss fire code
but eventually i got a o2 sensor code
after running it with the super rich mix
one or more of my injectors was stuck open
i din't have any fuel in vac line to regulator
and ohm test found a few bad injectors

good diagnossis
but don't say that the coils can't cause a miss fire code
a combination or problems can cause one code
or one problem u don't even think could cause the problem
the computer isn't smart
it only knows if some thing is wrong
so if its miss firing it will only know its missing
and not exactly way it is

i didn't have any codes telling me my injectors were bad
i didn't even have a miss fire code
but eventually i got a o2 sensor code
after running it with the super rich mix
one or more of my injectors was stuck open
i din't have any fuel in vac line to regulator
and ohm test found a few bad injectors


Of course we cant say it's always NOT the coils. Unfortunately these cars have a pretty prehistoric diagnostic system, in which one must use reason and proper judgement to diagnose and fix the problem. In my case, the injectors were trimming properly, and I believe the on-time was intact, only with full WOT fuel pressure which was flooding it out. Only codes I had were "Random Missfires" and "Missfire Cyl #6". For future reference, before the guy goes out and spends ~$200+ in new coils, wires, and plugs and pulling their hair out like I did, the FPR is a fairly easy check.

Thanks again for all the help guys.

Of course we cant say it's always NOT the coils. Unfortunately these cars have a pretty prehistoric diagnostic system, in which one must use reason and proper judgement to diagnose and fix the problem. In my case, the injectors were trimming properly, and I believe the on-time was intact, only with full WOT fuel pressure which was flooding it out. Only codes I had were "Random Missfires" and "Missfire Cyl #6". For future reference, before the guy goes out and spends ~$200+ in new coils, wires, and plugs and pulling their hair out like I did, the FPR is a fairly easy check.

Thanks again for all the help guys.


well it is very important to check everything before buying parts
cars are not like they use to be
all thought they are not as complicaced as some people make them out to be
they are deffinately not as easy to trouble shoot
with out access to some special tools and equpment they are all most impossible to find the exact problem

well it is very important to check everything before buying parts
cars are not like they use to be
all thought they are not as complicaced as some people make them out to be
they are deffinately not as easy to trouble shoot
with out access to some special tools and equpment they are all most impossible to find the exact problem

I think I may be too spoiled by my Audi's Motronic ECU system, which can pinpoint a simple burnt headlight bulb, to a system too rich/lean code such as this one. A burnt our coil pack is also clearly distinguish between a "Internal Resistance Too Low/High" code, to a simple "Missfire" code. [;)]

My 91 Lumina Euro 3.1 dies randomly.. its scaring me, i have been driving my 73 Chevy Cheyenne C20 Camper special ;) (with a 454 Big block 4:6:3 gears 12 bolt posi) and the truck is nice and all... but i would like to get more than 7 miles per gallon....

Now the lumina does not have any codes, always checked fluids, refilled when needed, all those kinds of things. timing belt was replaced at 120k miles, car now has 144k, and its not the transmission my car has the TH-125 (3 speed no overdrive) Now for what its doing.

The car randomly dies when warmed up, or at least i think only when warmed up. Once she starts dieing, she will keep doing it if you start her back up. When she dies you can feel a rpm surge sometimes and then she just dies, othertimes i dont notice it like if im in park its a nice and quiet car.

When she dies you can turn the key and start her right back up, and she runs like normal. It died on me a few times, one time i was getting on the freeway on one of those loops that go from an overpass to get to the freeway which is going another direction. she died about halfway through since there was no throttle input.

the other time i was just sitting in the parking lot at 7-11 waiting for my friend to get out of the store, and i went to shift and pressed the gas and she was dead. started right back up though.

the third time i was driving back from a few cities over, i was doing 65 MPH and 3000 RPM all of a sudden i feel a big grab, like something locked up in the tires and i look down at the Tach and wathced the needle bounce fro 3000 right down to about 700 or so and right back up to 3000 and stopped, the car kept driving like normal. so i gave her some more gas sped up to about 80ish since if shes going to be doing this i want to be home or at least closer to it. i felt her give me another one but smaller, so i was about 20 exits from my place, about 5 miles. i let off the gas a little, and the entire way back i can feel these little rpm drops and hear them too, but it was random.

now i went around and checked all the fuses, they are fine. Altenator is new within a year its fine, battery is fine, car could use some new spark plug wires and plugs but that cant cause this, its not ignition related im sure of that.

My grandfather is a GM tech, he was thinking that it could be electrical if it happened that fast. My brother tells me he think its a Vacuum leak, and my neighbor who is a GM tech said it could be a Fuel pump. But if it was a fuel pump could it still make it run fine untill it warmed up?

Im leaning towards a Vacuum line, can anyone give me any insight on this. i really want to get her fixed by this weekend.

Thanks
-Jeff

I had a lot of problems with stalling until I pull all the sensors and valves out of the throttle body and gave a a real good cleaning.

I had a lot of problems with stalling until I pull all the sensors and valves out of the throttle body and gave a a real good cleaning.



i know this is the lumina forum and not pontiac grand am
forum but
has any body had problems with the trans in those cars slipping in 1
and 2 but being ok in d
the car is my sisters
i don't drive it
but she told my dad who told me
and he thinks its the tranny on its way out
and i didn't know if a trans fluid change and filter change would help
or if the tranny is shot
he says the fluid looks ok
the engine is the 2.5 four cylinder
tranny is an automatic 3spd
don't know if its th125
the car has about 140000 miles
and never had the fluid changed
so i was hoping that would help
because i don't want to take out the transaxle
but i guess if i have to i will