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Thread: G8 Engine Issues

  1. #1
    Tuner in Training
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    G8 Engine Issues

    Hello,
    For some time I have been driving my G8GT with an idle issue and today is the last time I want to drive it until I fix it.
    Here are the problems:

    - Rev the engine, bliping throttle and letting go of throttle and engine comes down to idle and revs up as if I was bliping it for about 3-4 times to around 1500rpm. Then it corrects its self.

    - From a dead stop in drive, give it not aggressive throttle and hit brake hard, car wants to stall then BUCKS the RPMs or just stalls out.

    - Going for a "fun" drive and slam the brakes on until I come to a compleat stop, car stalls or BUCKS.

    The mods are cam 223/231, gears, converter, exhaust, intake. Very basic.

    I only use HPT for transmission tunes, so I am not familiar with engine tuning, could someone steer me in the right direction?

    The car has been professionally dyno tuned, not street tuned, long story.



    Thanks for any help!
    2000 Maple Red Metallic Trans Am A4, Grandfather Left It To Me
    LME 440 LS7|TSP LXR 285cc LS7x|278/286 .718 .702 112+4|Becks Intake 115mm|Direct Port|D&D T56 Mag|McLeod RXT
    2009.5 Pontiac G8 GT SMR||KOOKs 1-7/8"|Corsa|VaraRam|223/231 .610/.617 115+4|3.45s

  2. #2
    Tuner in Training
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    Here is a log,
    Check out at 2:05, 2:12, 2:31 watch the RPM drop. 2:43 is when it stalls.

    What does anyone think?
    Attached Files Attached Files
    2000 Maple Red Metallic Trans Am A4, Grandfather Left It To Me
    LME 440 LS7|TSP LXR 285cc LS7x|278/286 .718 .702 112+4|Becks Intake 115mm|Direct Port|D&D T56 Mag|McLeod RXT
    2009.5 Pontiac G8 GT SMR||KOOKs 1-7/8"|Corsa|VaraRam|223/231 .610/.617 115+4|3.45s

  3. #3
    Tuner in Training
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    At the end of the log is when I rev the motor and it almost stalls also.
    2000 Maple Red Metallic Trans Am A4, Grandfather Left It To Me
    LME 440 LS7|TSP LXR 285cc LS7x|278/286 .718 .702 112+4|Becks Intake 115mm|Direct Port|D&D T56 Mag|McLeod RXT
    2009.5 Pontiac G8 GT SMR||KOOKs 1-7/8"|Corsa|VaraRam|223/231 .610/.617 115+4|3.45s

  4. #4
    Tuner in Training
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    Can anyone help? Just a hint or something please?
    2000 Maple Red Metallic Trans Am A4, Grandfather Left It To Me
    LME 440 LS7|TSP LXR 285cc LS7x|278/286 .718 .702 112+4|Becks Intake 115mm|Direct Port|D&D T56 Mag|McLeod RXT
    2009.5 Pontiac G8 GT SMR||KOOKs 1-7/8"|Corsa|VaraRam|223/231 .610/.617 115+4|3.45s

  5. #5
    Advanced Tuner Niemer's Avatar
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    Your trans slip looks funny to me, but I'm afraid I cant be much more help. Try posting in the Gen 4 forum, those guys might be able to help.

  6. #6
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    Quote Originally Posted by Niemer View Post
    Your trans slip looks funny to me, but I'm afraid I cant be much more help. Try posting in the Gen 4 forum, those guys might be able to help.
    I might have the idle problem figured out thanks to Redline.
    Can you elaborate about the trams slip? Please.

  7. #7
    Advanced Tuner Niemer's Avatar
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    The logged pid "Transmission Slip RPM" goes from around 1000 to 0 and back at an idle, I'm not really sure what that PID is, but 0 slip at 0 MPH sounds to me like the equivalent of being on the brakes with the clutch engaged in a manual car. I don't know enough about it to say anything for sure.

  8. #8
    Advanced Tuner
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    What fixed your idle?

  9. #9
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    Added 2-4 grams to desired airflow below 800rpm & 2 add 2 degrees to idle spark
    2000 Maple Red Metallic Trans Am A4, Grandfather Left It To Me
    LME 440 LS7|TSP LXR 285cc LS7x|278/286 .718 .702 112+4|Becks Intake 115mm|Direct Port|D&D T56 Mag|McLeod RXT
    2009.5 Pontiac G8 GT SMR||KOOKs 1-7/8"|Corsa|VaraRam|223/231 .610/.617 115+4|3.45s