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Thread: Could scanning cause shift problems?

  1. #1
    Lifetime Member 87gmc's Avatar
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    Default Could scanning cause shift problems?

    When im data logging with black box it seems the 1-2 shift are delayed. When not connected to data port it shifts fine. Could the hardware be causing this problem? By the way its on my 99 GMC 5.3L Automatice 4l60 :?:

  2. #2
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    I've never experienced that kind of problem.
    I'd rather be blown, bored... AND stroked!
    Now: 447 CID (Corvette 427) , ATI Procharger D-1SC Supercharger

  3. #3
    Lifetime Member GMPX's Avatar
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    Default Re: Could scanning cause shift problems?

    Quote Originally Posted by 87gmc
    When im data logging with black box it seems the 1-2 shift are delayed. When not connected to data port it shifts fine. Could the hardware be causing this problem? By the way its on my 99 GMC 5.3L Automatice 4l60 :?:
    I just can't think of any reason this could happen.
    If you had a separate trans controller on the bus whose shift messages were being delayed because of the scanner then yes, but that is not the case with the PCM doing both.
    GM limit the amount of data the PCM sends back so it has time to actually run the engine and shift the trans.
    Does it only happen when you are actively logging, or just when the unit is plugged in?.

    Cheers,
    Ross

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