'90 3.1 Lumina stalling when warm

[Wilbur]

Thanks Torq,Yea I replaced coilpacks,ICM,Ecm,MAP,CPS,Fuel pump/filter,and it runs untill warm, then shutsdown,it will start back up, run rough, and die.Before it dies I can spray carb cleaner in its throat and it'll stay runnin.Everything I have replaced is new/not used(salvage yard) Wilbur P.S. Still getting Code 34(map low volt/high vac)

[Wilbur]

Would the fuel Pressure Reg. cause this problem?

[SappySE107]

Have you messed with the oil pressure sending unit? It has a wire in it that will kill your fuel pump if it reads 0 pressure. I think thats what its deal is. I had the wrong one in or I had bad wiring (didn't have the car long) but I had to mess with the oil pressure sender to get my car to start. It has to be something shutting off the fuel pump or its overheating or perhaps wiring to it.

[merlot566jka]

fuel pump,

i know this is old, was looking for coolant temp problems and saw this/...maybe he still needs help?

[Wilbur]

Thanks

Thanks merlot, that was the first thing I did believe it or not,that and the filter, and after about 500 bucks I left it sitting for about a year, and now with gas prices going through the roof I decided to try injectors I bought a used rail and all 6 injectors for $40 worked great and runs perfect, wanted to thank everybody for there help and input, Thanks Again Everyone

[IanSzgatti]

Just to further the value of this thread... the idea would be to use an ohm meter and touch a lead to each pin on the injector. on a 3.1 im sure 10 to nearly 13 ohms would be acceptable, but if one was particularly low it would be worth replacing.

of course, the problem here was the injector got warm and went open, so you can only ohm for this problem when the symptom shows itself

[Juglenaut]

Usually a bad fuel reg will cause the engine to run rich, and possibly throw a o2 code, rich black smoke out of tail on start up cold. Pulling the map should cause the engine to whimper and try to stall on a down rev but in most cases not.

I didn't think that OBD1 could override the fuel pump, don't see it on the schematic, if OBD1 monitored the oil pressure it would have a code right?? Even then when I changed my oil and after draining I can start the engine I only know this because way back I accidently started it before plugging or even adding oil. If it did I believe to prevent issues with a wire problem trobleshooting, if pressure is there a few seconds after starting a ground signal is monitored at the ECM from a pressure switch, if the ground is lost the engine in theory will not start and or will stall soon after starting, the reason I believe it is not a open circuit with pressure is then you wouldn't know if it was the wire or the switch, grounding the oil switch wire will rule out the wire.

I am pointing a possibility of the TPS and EGR problem since in closed loop the TPS, and EGR go hand and hand. Unplug the EGR and attempt a cold start.

[Wilbur]

I think I tried all that a year or so ago, this is an old Post, like I said the fuel rail fixed the problem, be it injectors or regulator, I think you gave me a reply on it a long time ago about 1 fuel injector circuit ties into 3 injectors, and if one is bad it shuts down the rest, so in turn when it reaches the 140 degrees where it runs in open loop (runs of of sensors and not off ECM presets) the fuel pump would shut down killing the motor, on a cool day (35- 40 deg.)it could take an hour or so, and take several hours to start back up, it was very frustrating.
All is good now runs great probably better than before, and I am back to saving fuel (Hemi 4X4 was killin me) and loving my3.1 . It should be good for a while I hope after replacing everything that I have, today oil and tranny fluid change so I can keep tooling around in my 18 year old Lumina Thanks again Juglenaut

[snakemandingo]

Another stalling Lumina on the chopping block!

Hey all, I have the same/similar problem with a 1990 Chevy Lumina 3.1 4 door. The car recently stopped running when it appeared to get hot but not over normal temp. I noticed that when it had cooled down the next AM, It will start and run fine. I have also tried driving the car a short distance, maybe 7-15 miles, and after shutting it off it will crank but not fire. I checked the codes and there none except the communicating code of 12. I have unplugged, cleaned and reconnected all the OBD sensor connections with no improvment. I will try all the suggestions and let you all in on the result.

Thanks.

[Wilbur]

Hey snakemandingo, I replaced everything on it, it costed me a small fortune, and finally I bought a used fuel rail w/injectors for it at the local salvage yard for $40 and it runs great and haven't had a problem since, it was the same as yours in every way, no codes, shutting down when temp got halfway up, restart after completely cool, hope this helps and good luck man...

[IanSzgatti]

Hey snakemandingo, I replaced everything on it, it costed me a small fortune, and finally I bought a used fuel rail w/injectors for it at the local salvage yard for $40 and it runs great and haven't had a problem since, it was the same as yours in every way, no codes, shutting down when temp got halfway up, restart after completely cool, hope this helps and good luck man...

yep. it's the windings of the injectors that cause an open circuit when hot and expanded... the circuit closes once they cool

[no2guncntrl]

Man I'm right in the middle of this same mess. I thought
it might be a ICM since I recall they die after a while.
Now if the same continues to thing happen, I'll send
the inj's to Lindertech for service.

Just great..I just found this. Check out the statement
on the 2.8/3.1 up to 93 Multecs..

http://www.lindertech.com/pattern_failures.htm

[snakemandingo]

Lumina 3.1 stalling

Hey no2guncntrl,

Finally getting back to the lumina stalling issue. Was your problem also solved with replacing the injectors prior to replacing everything else? This info would be a great help and $ savingings for me. The posts are very helpful when diagnosing the problem.

Thanks

[snakemandingo]

1990 Lumina 3.1 stalling

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!

[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.