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Thread: 1999 Trans am intermittent high idle with AC on

  1. #21
    Senior Tuner edcmat-l1's Avatar
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    Quote Originally Posted by SiriusC1024 View Post
    That's why I said vacuum leak. Brake cleaner trick doesn't always work. As MAP increases the effect of a vacuum leak diminishes. See the trims? Think the tuner left it like that? Extra air>extra fuel>extra spark = high idle.

    If the valley cover bolts weren't replaced with button heads then it's probably the intake manifold gaskets or cracked intake.
    Where did he say it had a FAST intake on it?

    Nothing about that data log screams vacuum leak to me. The dead giveaway is usually the MAF Hz. Even if you "tune around" a vacuum leak it will idle in a much lower MAF Hz cell.

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  2. #22
    Senior Tuner edcmat-l1's Avatar
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    Never mind. I just read it in that jumbled together paragraph.

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  3. #23
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    I'll double chack for leaks. when I installed the 102 I also used the button head bolts.

  4. #24
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    I apologize was trying to write that quick while I was at work.

  5. #25
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    Quote Originally Posted by DillyBar View Post
    I'll double chack for leaks. when I installed the 102 I also used the button head bolts.
    The reason brake cleaner won't work is because LTFT's, which STFT's indicate as locked in, are making it stoichiometric. You'd have to disable closed loop, including STFT Open Loop, then clear stored LTFT's. Even then there are things like the spark over/underspeed tables and idle airflow adaptives that'll try to hold idle rpm.

    Make sure it's not that non-flammable crap. I had an idiot friend try to use that in a potato gun one time.

  6. #26
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    I double checked for vacuum leaks. I borrowed a friend's smoke tester and couldn't find a leak anywhere. Any other ideas?

  7. #27
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    If it's sealed up, fuel pressure is good, and the injector data is for the injector installed, then move on to tuning VE.

  8. #28
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    Quote Originally Posted by DillyBar View Post
    I double checked for vacuum leaks. I borrowed a friend's smoke tester and couldn't find a leak anywhere. Any other ideas?
    Get a log with all the things we asked for earlier.
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