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Thread: Increasing RPM & Speed with O Throttle Pedal Input

  1. #1
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    Default Increasing RPM & Speed with O Throttle Pedal Input

    I have a 5.3L with 4 speed auto transplanted into a 68 Chevelle that I have tuned. It runs and drives great. When you pull it into gear then let go of the brake with no throttle input the car will start moving and increasing speed even shifting. It seems TAC_PCT% is increasing but I cannot find what is driving it. When coming to a stop and stopping it takes a long time for the TAC_PCT% and RPM to reduce. Attached are engine and trans cals plus a logs.
    Dennis_68_Chevelle_12614085_29June2018_Idle_0014.ctz
    Dennis_68_Chevelle_24238856_TCM_12May2018_0002.ctz
    Dennis_Idle_29June2018_0002.efi
    Dennis_Idle_29June2018_0001.efi

  2. #2
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    Interestingly it operates properly when cold, below 80C.
    Thoughts

  3. #3
    Joe (Moderator) joecar's Avatar
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    I'm looking thru your files to see if I can see what's causing it...

  4. #4
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    Thanks Joe
    I’m perplexed

  5. #5
    Joe (Moderator) joecar's Avatar
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    What year/model/vehicle are your ECM/TCM from...?

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    It's out of a 2007 Silverado 1500 the motors a 5.3

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    Any thoughts on what could be causing this.
    Thanks

  8. #8
    Joe (Moderator) joecar's Avatar
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    I'm still scratching my head.

  9. #9
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    LOL
    It is a perplexing one :(

  10. #10
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    Quote Originally Posted by TurboCamaro View Post
    I have a 5.3L with 4 speed auto transplanted into a 68 Chevelle
    Now there's your problem... a 68 Chevelle requires a 6.0L engine. Installing a 5.3L is almost criminal.

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