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Thread: Wild spark, unstable idle after flash

  1. #1
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    Wild spark, unstable idle after flash

    Hello
    2015 C7 stingray z51
    First time flashing a gen 5 LS ecm,
    Made some changes to the stock file, flashed it, car wont idle or drive correctly, spark is unstable,
    p0300 misfire codes, flash back to stock and all is well...
    odd???
    anyone else have this issue?

    Fixed after re-reading stock file and re-editing it.
    Last edited by Cranked Automotive; 07-20-2021 at 02:01 AM.

  2. #2
    Senior Tuner SultanHassanMasTuning's Avatar
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    which version of software are you using?
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  3. #3
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    Quote Originally Posted by SultanHassanMasTuning View Post
    which version of software are you using?
    Newest stable version, updated it last week, could be due to deactivating too many dtcs. Or not downloading the stock file after holding down the ignition button for 6 seconds to get the vehicle into true KOEO.

  4. #4
    Senior Tuner SultanHassanMasTuning's Avatar
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    try to disconnect battery for a while and connect.
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  5. #5
    Senior Tuner SultanHassanMasTuning's Avatar
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    try to disconnect battery for a while and connect.

    i always hold down the ignition key for 6 to 7 seconds to read file
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  6. #6
    Senior Tuner Ben Charles's Avatar
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    My first question would be what changes are you making

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  7. #7
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    Quote Originally Posted by Ben Charles View Post
    My first question would be what changes are you making
    Vehicle has long tubes
    I believe the issue was o2 sensors> feedback> i set it to single instead of the factory setting of dual
    Or it was disabling all of the o2 sensor 2 codes.

    Haven?t had an issue now since i reflashed it to stock and then reread and made all the changed only to the dtcs that came active on their own and leaving the o2 feedback setting alone.
    Last edited by Cranked Automotive; 07-21-2021 at 08:51 PM.

  8. #8
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    Quote Originally Posted by SultanHassanMasTuning View Post
    try to disconnect battery for a while and connect.

    i always hold down the ignition key for 6 to 7 seconds to read file
    Thanks for this, i read it on another thread and it was the only way to flash entire due to timing out.

  9. #9
    Tuner in Training
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    Had the same problem with a 6th gen camaro that was tuned before , if I ever change any parameter on the file regardless what it was , the car wont be stable at idle , I have ended up loading a stock file and start over . Still have no idea what was the problem .

  10. #10
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    Does the car have one of those Pedal Controller units that plug into the gas pedal? These will cause all sorts of issues every time you flash a car. They must be removed when flashing.
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  11. #11
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    Quote Originally Posted by TriPinTaZ View Post
    Does the car have one of those Pedal Controller units that plug into the gas pedal? These will cause all sorts of issues every time you flash a car. They must be removed when flashing.
    Car is completely stock other than long tubes.
    Problem was fixed by flashing back to stock and then downloading the stock file again.