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Thread: E40 randomly wont prime fuel pump...

  1. #1
    Lifetime Member BLK02WS6's Avatar
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    Default E40 randomly wont prime fuel pump...

    06 GTO randomly wont prime the fuel pump when hot... if you turn the key on (but not start) several times, it will eventually do the prime and then fires right up - sometimes takes 2 or 3 key ons, sometimes takes 10 - very random, but always when hot... also, it is the signal coming from the PCM that is the problem - verified with a test light that the problem is from the PCM.

    any ideas???
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  2. #2
    Joe (Moderator) joecar's Avatar
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    PCM pin is loose or corroded;
    wiring is damaged;

    ( and for completeness, re-seat the relay, but from what you said I don't believe it's this )

  3. #3
    Lifetime Member BLK02WS6's Avatar
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    Yeah, not the relay, already checked that. Can't find any loose/corroded wires or pins either... any chance it is in the PCM itself? customer is irritated and wants to change the PCM at this point... car has been great for 3 years and just started doing this - no mods or changes...
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  4. #4
    Joe (Moderator) joecar's Avatar
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    It could be the PCM... PCM's don't usually go bad, but it's possible.

  5. #5
    Lifetime Member BLK02WS6's Avatar
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    I know it's unusual, but I've seen a couple just start acting wierd - after exhausting all other diagnostics, we replaced them, flashed the same tune we were using, and all is well...
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  6. #6
    Joe (Moderator) joecar's Avatar
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    Glad it works

    After reading the symptoms again, it sounds like a dry/cracked solder joint on the PCM circuit board (at the fuel pump relay driver/transistor).

  7. #7
    Lifetime Member BLK02WS6's Avatar
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    Quote Originally Posted by joecar View Post
    Glad it works
    I was refering to past ones with wierd issues - guess I should have said all "was" well - haven't gotten this one straight yet - they are looking for a PCM though...
    GM EFI Tuner
    02 WS6 9.41 @ 143 MPH 3675#, drag radials, pump gas, through the mufflers - sold


  8. #8
    Joe (Moderator) joecar's Avatar
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    Oh, premature...

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