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Thread: Repinned a 1998 to a 2002 PCM C5 corvette now it won't start

  1. #1
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    Repinned a 1998 to a 2002 PCM C5 corvette now it won't start

    1998 corvette ran great, so naturally, I wanted to add another 200+RWHP.
    Stock LS1. Then I added a custom rear turbo from another forum member, bigger heads, cam, Lonnie's fuel pump, etc. No MAF, speed density 2 bar.
    I also bought a used 2002 PCM and did the re-pin. Bought HP tuners, and installed (several different) tunes trying to fix this problem:

    It will not start. It just turns over and over. I have checked and double-checked everything I can think of.
    New battery, spark plugs, oil, coolant. Fuel pump works. I have 60psi fuel going through the lines, coils are working, battery has 12.6 volts, etc.
    No errors in the DIC except the gas cap.

    I did not change the VIN after the re-pin. The tune calibration details reads 2002 GM LS1. Could this be the problem? I am running out of ideas.
    Here is a copy of the latest tune. Thanks for any and all suggestions.
    newer stock tune 2 bar map 6-8-19.hpt

  2. #2
    Advanced Tuner Montecarlodrag's Avatar
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    Stupid question:
    Did you disable VATS in the 2002 tune?
    9 sec Montecarlo SS

  3. #3
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    Quote Originally Posted by Montecarlodrag View Post
    Stupid question:
    Did you disable VATS in the 2002 tune?
    Yes.

  4. #4
    Tuning Addict blindsquirrel's Avatar
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    Do a fresh read of the file in the PCM, compare it to the one you've been writing. See if the VATS status actually has been changed - just because it's correct in the file on your PC doesn't mean it is that way in the PCM, won't know for sure until you compare them.

  5. #5
    Tuning Addict 5FDP's Avatar
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    Post up a log file too.

    And what injectors did you install?
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  6. #6
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    Does it have spark? Does it have injector pulse? (checked with noid light) Does scanner show rpm when cranking?

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    you are in open loop go to DTCs and change PO101,PO102 and PO103 to NO MIL Light.

  8. #8
    Tuning Addict 5FDP's Avatar
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    What's the difference?

    First error does what he wants it to do.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  9. #9
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    Change MAP Sensor Linear to 200.00 And MAP Sensor Offset to 10.33 Car will start.

  10. #10
    Tuning Addict blindsquirrel's Avatar
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    Quote Originally Posted by C5 2000 View Post
    Change MAP Sensor Linear to 200.00 And MAP Sensor Offset to 10.33 Car will start.
    The tune in the first post has linear/offset already set to 207.66/9.00 which seems rather specific, pretty good chance those numbers weren't just picked at random.

  11. #11
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    Quote Originally Posted by blindsquirrel View Post
    The tune in the first post has linear/offset already set to 207.66/9.00 which seems rather specific, pretty good chance those numbers weren't just picked at random.
    To answer the above suggestions:
    Did a read. VATS is disabled.
    60# injectors. Yes to spark on all 8.
    No MIL light didn't change anything. Changing the MAP settings didn't change anything.

    But please keep the suggestions coming. Something has to work.
    Last edited by diabloownr; 06-18-2019 at 10:18 PM.

  12. #12
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    Quote Originally Posted by diabloownr View Post
    To answer the above suggestions:
    Did a read. VATS is disabled.
    60# injectors. Yes to spark on all 8.
    No MIL light didn't change anything. Changing the MAP settings didn't change anything.

    But please keep the suggestions coming. Something has to work.
    It takes air fuel and spark to fire. Do you have injector pulse as checked with a noid light. See if it will fire with spraying starter fluid.

  13. #13
    Tuning Addict blindsquirrel's Avatar
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    Fuel pump prime at key on, pump runs while cranking?

    Fuel pressure?

    Injector pulse?

    Does it fire if you spray it with (insert flammable aerosol of choice here)?

    You say 60# injectors, tune looks set up for something more like 80's?

  14. #14
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    Quote Originally Posted by blindsquirrel View Post
    Fuel pump prime at key on, pump runs while cranking?

    Fuel pressure?

    Injector pulse?

    Does it fire if you spray it with (insert flammable aerosol of choice here)?

    You say 60# injectors, tune looks set up for something more like 80's?
    Pump primes, pump runs while cranking.
    60psi through the fuel rails.
    Checked with NOID. Injector pulse on all 8 while cranking.
    60# Deka injectors. Set with info from their website.

  15. #15
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    Unless someone talks me out of it, I am going to undo the repin and put the 98 PCM back and see if it will start.

  16. #16
    Tuning Addict blindsquirrel's Avatar
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    You have air, spark, and fuel - well, maybe not fuel, injector pulse doesn't prove fuel is spraying.

    But the wrong amount of air, spark at the wrong time, and wrong amount of fuel will make it not run just the same as one of the three not being present.

    Does it do anything at all when cranking? Pop, chug, thump? Have you sprayed it with something flammable? Has it ever run with these injectors? Are the plugs wet, or dry? Have you tried changing anything like cutting the Min Injector Pulse in half (it's only a little less than stock, much higher than I see for other P01/80lb tunes). Min pulse, your Offset being nearly double the stock numbers around cranking voltages, plus injectors that are ~2.5x bigger than stock, my guess would be it's delivering way too much fuel.

  17. #17
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    Quote Originally Posted by blindsquirrel View Post
    You have air, spark, and fuel - well, maybe not fuel, injector pulse doesn't prove fuel is spraying.

    But the wrong amount of air, spark at the wrong time, and wrong amount of fuel will make it not run just the same as one of the three not being present.

    Does it do anything at all when cranking? Pop, chug, thump? Have you sprayed it with something flammable? Has it ever run with these injectors? Are the plugs wet, or dry? Have you tried changing anything like cutting the Min Injector Pulse in half (it's only a little less than stock, much higher than I see for other P01/80lb tunes). Min pulse, your Offset being nearly double the stock numbers around cranking voltages, plus injectors that are ~2.5x bigger than stock, my guess would be it's delivering way too much fuel.
    Pops once (or twice) when I first turn the key to start, and then just turns over and over. I have not sprayed it. I bought the injectors off of a forum member, who used them for 6k miles. Plugs are wet. I will try changing the tune to what you suggest. Thanks.

  18. #18
    Tuning Addict blindsquirrel's Avatar
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    There are so many unknowns here... one thing I can say for sure though: If the spark timing is close, and you disable the fuel pump, and the plugs are dry(ish), and you spray it with brake/carb cleaner, it will fire or at least do something. We used to drive cars into the shop with dead fuel pumps all the time, one guy driving and another guy sitting on the front spraying brake cleaner at the throttle body. It'll run surprisingly well like that, too.