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Thread: Intermittent P0340,P0341 Long Crank starting

  1. #1
    Tuner in Training
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    Mar 2017
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    Intermittent P0340,P0341 Long Crank starting

    LSX 376 B15 throwing P0340,P0341 intermittent IE: 5% of starts
    Have seen higher consistency of P0341 on pulls higher than 5k IE: 20% of the time.
    Long cranks greater than 10s are 80% of the time, with about 20% requiring 2nd crank.
    Seems like week,slow starter when hot, meaning semi slow to turn engine over, starts fine, just slow, not same as long crank.

    https://www.youtube.com/watch?v=LFKL990i0bE Maybe Alternator, not sure what sensor on HP Tuners?

    Attached are couple diag's "New to HP Tuners...."
    Trace show Cam Sensor Counts stop counting
    Cam Sensor has been replaced, no change in observed results.

    Have read anything from bad grounds, bad starter, bad primary wire from battery to starter, alternator.....

    Hoping others have ideas on Diagnostics to watch to help troubleshoot?

  2. #2
    Tuner in Training
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    Mar 2017
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    Attached images with Highlighted areas where Cam Counters Stopped incrementing....

  3. #3
    Tuner in Training
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    Mar 2017
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    Tune file attached as well.
    Attached Files Attached Files

  4. #4
    Tuner in Training
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    Upgraded battery from rated 640 CCA to a 850 CCA.
    Fingers crossed, so far, after few over 5k accelerations, no Cam Counter stalling as yet.
    Turns over significantly faster when starting now.

    This is a 5.3l LH9 to a 6.2l LSX swap, so, battery may not have had the cranking amps required.

    Attaching recent accelerations log, not WOT runs as yet.

    Tuning 4L60E shift points as well and having 2nd to 3rd over-rev or flares as they may be termed.
    Last edited by RonVC; 12-31-2019 at 05:52 PM. Reason: Add Layout and ScreenCapture image

  5. #5
    Tuner in Training
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    Mar 2017
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    FYI, Higher CCA Battery has resolved the Intermittent P0340,P0341 Long Crank starting

    Maybe there is a weak ground that the higher amp battery has overcome.