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3.1 stalls and won't restart


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male114
New User

Feb 23, 2008, 5:34 PM

Post #1 of 4 (2867 views)
3.1 stalls and won't restart Sign In

i have a 2002 pontiac grand prix with a 3.1 engine. vehicle runs until it reaches operating temp and then shuts down and won't restart. maintains approx. 50 psi fuel pressure when cranking and unit will start with starting fluid and then shut right down which tells me the plugs are firing. i'm guessing that something is stopping the injectors from firing. can anyone tell me what sensors could keep the injectors from firing. scan tool shows both crank sensors are operating and i have already replaced the cam sensor. vehicle will start back after cooling off.


autojoe
User

Feb 24, 2008, 11:44 AM

Post #2 of 4 (2855 views)
Re: 3.1 stalls and won't restart Sign In

should be 52-59 psi key on engine off.What is your fuel pressure with car running and as car stalls?


male114
New User

Feb 24, 2008, 4:24 PM

Post #3 of 4 (2849 views)
Re: 3.1 stalls and won't restart Sign In

about 48 psi. pressure stays up until engine quits and then falls


autojoe
User

Feb 25, 2008, 9:55 AM

Post #4 of 4 (2842 views)
Re: 3.1 stalls and won't restart Sign In

48 seems little low.if you turn key on for few seconds off few seconds on ect. to see if fuel pressure will go higher and crank to see if starts.Could disconnect injector harness multi-way connector and probe appropriate fuel injector control circuit at pcm side of the fuel injector harness multi-way connector with a test light connected to battery positive and crank engine and see if test light flashes.This would tell you if pcm is pulsing injectors. (C)BLACK WIRE number 1 injector.(D)LIGHT GREEN/BLACK WIRE Number 2 injector.(E)PINK/BLACK WIRE Number 3 injector.(F)LIGHT BLUE/BLACK WIRE Number 4 injector.(G) BLACK/WHITE WIRE Number 5 injector.(H)YELLOW/BLACK WIRE Number 6 injector.Do when it won't start.Do you have any stored codes on pcm?If you had enhanced scan tool it would list cylinders 1-6 injector circuit status parameters okay or not.Something electronic is shutting down.I hope not pcm very expensive plus to have flashed but then again what isn't expensive these days.The injectors may be working but the pulse width may be narrow based upon inputs from various sensors.Could do a fuel pump volume test.I would suspect the injectors would test okay.Good spark.....fuel pressure little low?What does your scan tool show for pulse width while cranking?






 
 
 






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