'90 3.1 Lumina stalling when warm

[CNCguy]

The ECM has a rev limiter when the trans is in Park or Neutral. Since it stalls/hesitates during accel, I would suggest checking or replacing the TPS (throttle position sensor).

[Roadbastard]

When my car did this it was the head gasket. It would be fine you first started it up, and then as soon as it got hot enough no dice and the motor killed off, probably because of all the coolant spewing into the piston chamber. Thought it was the icm so I changed that and just about anything electronic related that could kill the motor of. It was a small leak. Didn't know how bad it was till I dropped the pan and saw all the yogurt waiting for me. Probably the worse case Scenario but my car leaked for a year leading up to it eventually getting hot and dying never know. Sometimes its something simple and sometimes its something that will make you cry.

[burgermen]

1990 lumina troubles

hey everyone! have a 1990 3.1 lumina sedan. It runs rough, stalls and cuts out when accelerating too fast? Also cold or hot engine loops then cuts out when revving too high in park. Have replaced fuel pump, filter, crankshaft positions sensor, checked ICM and coils. help! and Thanks!

[snappin]

Did you get this resolved? I'm having the same problem on my lumina as well.

[no2guncntrl]

There is a guy over at this forum that was saying these things are
notorious for half a** ECM's. Course don't go changing out the ECM
om my word, but you might take it up and have it tested. I guess you
did check out the ICM. Here's that site. Might find some help..>

http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=1100

Oh, I was just reading the whole thread over again and saw Manic is helping
you out. He's trying to help me, but I've dropped the ball. Hope you find
the prob.

[snakemandingo]

OK next time you get no spark, disconnect ICM 2 pin connector and make sure there's ignition voltage with key on. Then unhook ICM 3 pin connector and measure for proper resistance of the crank sensor, about 1K ohms, at yellow and purple wire I think. If you have a voltmeter that measures A/C current check it for the pulsing signal, or if you have a scanner it should show rpms when cranking. If this checks OK and you have no spark the ICM is most likely the problem.


The main thing is if you're getting a crank signal from your crank sensor and no spark then it just about has to be a faulty ICM.

Hey Manic, 2 and 3 pin checked out OK. I found a new symptom while waiting for the engine to warm up then shut down. When I was warming up the engine, I kept the rpms a little high because I noticed the engine stumbled one time prior before stalling. Once the engine began stumbling, I fully accelerated the engine (from under the hood at the throttle body) and was able to keep the engine running. However, the stumbling was really bad and I could hear the engine fire back through the intake plenum into the air filter area a couple of times. So apparently there is enough spark to keep it running yet it immediately stalls when the accelerator is released. Also, The Catalytic converter is extremely hot for the short 10 minute warm up. any ideas anyone?

[manicmechanix]

When cold the car appears to run fine. Approximately 10-15 minutes later idling (warm up) it will stop running. Upon cranking after it has stopped, the spark plug wires, which while running showed spark, will not show spark from any of the three coil packs. I have taken the ICM and coils to a shop that tested them both OK. I even went as far as bringing a hot air gun and heated up the ICM to a blistering surface temp (much hotter than it is attached to the block) and multiple tests were OK.

OK next time you get no spark, disconnect ICM 2 pin connector and make sure there's ignition voltage with key on. Then unhook ICM 3 pin connector and measure for proper resistance of the crank sensor, about 1K ohms, at yellow and purple wire I think. If you have a voltmeter that measures A/C current check it for the pulsing signal, or if you have a scanner it should show rpms when cranking. If this checks OK and you have no spark the ICM is most likely the problem.


The main thing is if you're getting a crank signal from your crank sensor and no spark then it just about has to be a faulty ICM.

[snakemandingo]

Stalling 3.1 Lumina

I thought you said your car ran until it gets hot then stalls and it loses ignition spark? Will it run until hot before stalling? And does it actually lose ignition spark? If so, this might be a case where your ICM and coils (more likely the ICM though) craps out when hot. This might be a case where you might want to go to the junkyard and get substitute ICM with coils for cheap and try it out.

Does it run till hot and lose spark or what? also your not getting a CPS code when this happens are you?

When cold the car appears to run fine. Approximately 10-15 minutes later idling (warm up) it will stop running. Upon cranking after it has stopped, the spark plug wires, which while running showed spark, will not show spark from any of the three coil packs. I have taken the ICM and coils to a shop that tested them both OK. I even went as far as bringing a hot air gun and heated up the ICM to a blistering surface temp (much hotter than it is attached to the block) and multiple tests were OK.

[manicmechanix]

Had the ICM tested along with all 3 coil packs and passed. I will be rechecking the fuel pressure at running, stalling and post stall cranking. You know you're getting bummed out when you start hoping for a part to test bad.

I thought you said your car ran until it gets hot then stalls and it loses ignition spark? Will it run until hot before stalling? And does it actually lose ignition spark? If so, this might be a case where your ICM and coils (more likely the ICM though) craps out when hot. This might be a case where you might want to go to the junkyard and get substitute ICM with coils for cheap and try it out.

Does it run till hot and lose spark or what? also your not getting a CPS code when this happens are you?

[snakemandingo]

The problem I am having has not been resolved....just narrowed down. I would get a auto parts store in your area to test your ICM and coil packs prior to the purchase of a new one. Mine were all OK and now I will have to move on to the next step....whatever that is?

[no2guncntrl]

I haven't even worked on since the last time I posted. I got a
factory service manual which sent me looking for things UNDER
the engine's fuse box area. I'm going to install the new ICM
when it warms up here and see what happens. Next stop
will be inj. I'll go with the Bosch. What a PITA..I'm glad
someone got their 3.1 going again. I hope to as well.
n2gc

[snakemandingo]

Had the ICM tested along with all 3 coil packs and passed. I will be rechecking the fuel pressure at running, stalling and post stall cranking. You know you're getting bummed out when you start hoping for a part to test bad.

[manicmechanix]

I agree with your fuel injector idea. I previously tested the fuel rail pressure (post stall) while cranking it was at 35-37psi and increased to 40+psi within minutes after I stopped cranking. I assume the pressure rose due to the injectors being closed and fuel heat expansion.

Yeah, I think to check the that the fuel injectors are opening you would check fuel pressure before cranking and see that it had around 41 psi. But unhook the pressure regulator vaccuum hose, then crank and see that fuel pressure drops. If you leave the regulator vacuum hose attached it might pull enough vaccuum to lower while cranking, but I'm not really sure if you ned to unhook the vaccuum. But the bottom line is the pressure should drop while cranking if the injectors are opening since the fuel pump doesn't run while crank, or does it lol?

Anyway your problem really sounds like it's the ICM.

[snakemandingo]

Hey Mainc,

I will get the ICM tested as you eliminated my ICM spark interrupt suspicions. I agree the exhaust temp may be the contributing factor.

I agree with your fuel injector idea. I previously tested the fuel rail pressure (post stall) while cranking it was at 35-37psi and increased to 40+psi within minutes after I stopped cranking. I assume the pressure rose due to the injectors being closed and fuel heat expansion.

As mentioned in earlier posts, there were never any codes found.

I will keep you all posted! (so to speak)

Thanks

[manicmechanix]

Hello again,

I forgot to mention, I thought it was the ICM due to the fact that there is no spark to the plugs when cranking after it warms up and stalls. I am told by a local auto parts store they can test my particular ICM. Also, I have checked the TPS, power source to the ICM and oil pressure switch. A additional question I have is, would something be signaling the computer to shut off the spark to the plugs after it stalls to preserve the engine? I am hoping to reduce the amount of remove and replace work involved with a misdiagnosis.

Thanks again for everyone's help!

No nothing other than the oil pressure sensor or low battery voltage will cause the computer to intentionally shut down the fuel injectors/fuel pump. I don't think it ever shuts the ignition down on the 3.1. Just have your ICM tested. I guess on the 3.1 the ICM being near the exhaust makes it run hot perhaps.

Regarding the injectors, I read through this thread and I didn't see that Wilbur made it clear whether the fuel pump was or wasn't supplying fuel pressure when engine was hot and stalling/no start. Anyway, those Multecs do screw up. And the newer Multec 2's also plug up from deposits. I don't know if I'd do all that work to replace the injectors and trust it to junkyard ones even if their resistance was in spec, but you can't be that price .

On the 3.1, all 6 injectors are wired together and they all fire simultaneously-twice per crank revolution I think or maybe once-that's not really important. There's only one injector driver (well there's 2 injector drivers in the OBD1 ECM, but the 3.1 wires them together). Anyway, you check the resistance at the main injector harness near the engine and are checking the overall resistance. If it's off spec, then off comes the upper intake manifold and then you can check imjector resistance individual. I don't see how you could get an ohm meter on each injector with the manifold on.

I can't remember the diagonistic for the 3.1, but had he tested fuel pressure while cranking wouldn't it drop some s specific amount normally and if not that clue in on the injectors?

One other lesson in this thread is one should never guess and try to diagnosis by replacement. It'd be cheaper, and probably easier and faster to take it to a dealer and pay for the $90 or so diagnostic. If a sensor isn't throwing a code, then it's more than likely not the culprit. Test the suspected part and only replace it if it tests bad.