Mechanics

3.1 LITER

2002 Pontiac Grand Prix • 127,000 miles

I have a 2002 Grand Prix 3.1 liter that won't start. I have spark and it will hit with starting fluid. I have 59 psi fuel pressure on the rail. I have 12 volts on the pink wire to the injectors which tells me I must not be getting an injector pulse, to verify I would have to remove the upper intake. A Mechanic gave me an ICM to try and I have same symptoms with it. G.M. Mechanic says the crank sensor is good or I wouldn't have spark. Any ideas?
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Davekyguy
August 12, 2011.



Do you have a security light on/blinking? Do you have accsess to a scanner, can you scan for dtc's?


PROTECH1980
Aug 12, 2011.
No security light blinking. Car was running rough intermittently the day it started. Tachometer would dance around and then stay at 0 for a long period of time only to act normally for a while then act up again, this happened when the car was not even missing. I shut car off and it would not restart. Code PO401 EGR flow insufficient. After disconnecting the battery for a while the car started, I drove it 3 miles and shut it off and it will not start at all now, even after disconnecting the battery.

Thanks


Tiny
Davekyguy
Aug 12, 2011.
Meant to mention the EGR code was because a mechanic suggested I disconnect the EGR valve to see if that was the problem.


Tiny
Davekyguy
Aug 12, 2011.
One more interesting symptom. If I disconnect the battery for a few hours and reconnect it the car will start. If I shut it off and try again it will NOT start. I know everyone may say ECM but I read of another car same model that did exact same thing and ECM did not fix it. The person never posted what did fix it. . I am going to check some sensors then yell real loud. My thoughts are, maybe ECM, or maybe it is getting no signal from a sensor that clears when batt. Is disconnected only to come back when it finally starts. I know TPS could be stuck in clear flood mode so i'll check that. Any help would be appreciated.
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Tiny
Davekyguy
Aug 12, 2011.
***Ok, here is what I know now. Have spark, have 59# fuel pressure. Spray starting fluid in intake and it hits. Cam sensor ok because when cranking I get 200rpm or so on code scanner, also because I have fire to plugs. ICM is good because I tried another one. Security light does not flash and bulb is good. Dis-connect battery a few hours and it starts and runs but will not restart if turned off.

If anyone don't have any suggestions I'm going to throw some money at a computer and more for the dealer to program it.

Thanks


Tiny
Davekyguy
Aug 12, 2011.
Update. I disconnected the battery so the car would start, drove it 20 miles and it gave a crank sensor A fault, I replaced that and same problem. I also found if I pull the ecm fuse for 40 minutes the car will restart. If I turn it off it won't start. If I drive it for 20 minutes or so it will restart until it cools down. Tach also goes crazy until it runs 20 minutes and then it functions normally.

Found someone online with exact same problem and it was a bad wire.


Tiny
Davekyguy
Aug 17, 2011.

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