Strange sound behind the dash at high rpm

Discussion in '96-04 - 2V Specific' started by Adam Vinnicombe, Nov 19, 2020.

  1. evilcw311

    evilcw311 Most Evil Member! SN95 Supporter

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    Thats more for those who mess with tuning. You should definitely see a change but I’m not sure how those numbers would swing. While you were fixing the one line did you take the time to verify there was no other leaks??


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  2. Adam Vinnicombe

    Adam Vinnicombe Active Member

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    I’ve look all over the car now and have not found any other vacuum leak at all. What I did do as an experiment as I am still learning the basics here was to plug in my data logger and watch the fuel trims at idle, then I pulled the blue vacuum line back of and watched the STFT instantly react by going +8 while at idle and slowly decrease back to +1 as the rpms went up. So I can definitely say that that little vacuum leak was messing the fueling up when at idle
     
  3. ttocs

    ttocs Post Whore

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    unmetered air would have to throw those off I would think.
     
  4. white95

    white95 Apex Junky Admin

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    Smoke test
    Smoke test
    Smoke test
    Smoke test
     
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  5. evilcw311

    evilcw311 Most Evil Member! SN95 Supporter

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    You can’t do a visual check for vacuum leaks. Either get a smoke machine to test it or do what I do and get a cigar and do it the cheap easy way.

    Smoke test is your easiest way to verify no more leaks.


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  6. Werecow

    Werecow Well-Known Member

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    ^^^^ agree... Then dig out yer trusty ol vacuum guage...
     
  7. Adam Vinnicombe

    Adam Vinnicombe Active Member

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    Right today I’m going to go and see if I can buy me a vacuum gauge but as I said I’m still learning here where is the best place to plum it in ?
     
  8. Adam Vinnicombe

    Adam Vinnicombe Active Member

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    Well some good news done the cigar smoke test and found no leaks anywhere which was nice but my fuel trims are still negative at idle but all jump to a constant 0 to +3 just above idle when in neutral
     
  9. vitory34

    vitory34 New Member

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    I found interesting information about information about Torque of differential and driveshaft , and also how the Temperature can affect to the performance.
    www.motorcloud.com