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2002 Pontiac Grand Prix Question: WHY WILL CAR NOT RUN UNLESS I SPRAY FUEL DIRECTLY INTO INTAKE- SPARK IS STRONG.

 

Question

HWY20, 3.1L V6, Waterloo, AL, July 16, 2013, 07:39
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FUEL RAIL PRESSURE IS AT 45 PSI-HAVE CHANGED ICM,CRANK POS SENSOR, PRESSURE REG, MASS FLOW SENSOR.
THE ONLY CODE STORED WAS FOR THE O2 SENSOR. NO OTHER CODE STORED. I SUSPECT THE PCM,BUT DON'T KNOW PROPER PROCEDURE TO CHANGE IT. PLEASE HELP AND THANKS!

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  • Answer #1

    pushrod July 16, 2013, 07:50
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     Master

    Check for injector pulse with a noid light! Post results. Need this info. first! If you dont have the GM MPFI noid light, parts store may rent/loan you one. Dont have the pressure specs here, but best i can remember that's enough. (45 psi)

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    HWY20, July 18, 2013, 18:50
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    CHECKED WITH A NOID LIGHT-NO SIGNAL-NO LIGHT ,NOTHING

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    pushrod, July 18, 2013, 20:42
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     Master

    Most likely the ecm injector driver is defecfive. Need to check the circuits to be sure ,once you buy this preflashed computer, it's yours! You need a wiring schematic for testing! If there is a shorted circuit you may fry the new ecm also. If there is an open circuit you can repair that!
    Good luck with it.

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    HWY20, July 19, 2013, 04:55
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    IF THE CIRCUITS CK OUT GOOD-I WILL REPLACE THE PCM THAT HAS BEEN PRE-FLASHED. MY QUESTION IS, DO I NEED TO HAVE IT REPROGRAMED BY A GM DEALER AFTER INSTALLATION?
    AND IF THE PCM IS THE PROBLEM, AND THE REPLACEMENT IS NEEDED, WILL IT RUN TO THE DEALER SHIP TO HAVE IT REPROGRAMED,OR WILL I HAVE TO TOW IT TO THE DEALERSHIP.
    I AM A RETIRED MECHANIC, BUT DO NOT HAVE VERY MUCH EXPERIENCE WITH PCM OR ECU'S. THANKS AGAIN

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    pushrod, July 19, 2013, 06:28
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    Call parts store, some can be done pre purchase and all you have to do is install. You will need the vin and computer numbers.

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    pushrod, July 19, 2013, 06:28
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    Call parts store, some can be done pre purchase and all you have to do is install. You will need the vin and computer numbers.

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