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Thread: Help!.. LTFTs out of control!!

  1. #1
    Potential Tuner
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    Jun 2004
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    Help!.. LTFTs out of control!!

    Ok, here goes...

    99 Cam z-28 a4, slp longtubes, slp cats, slp loudmouth, granatelli lid, stock maf w/ported housing, tb bypass, k&n, everything else is stock..

    ok, when i purchased my car, it had hypertech on it, i "deprogrammed" my car, however i think it leaves stuff in there.. who knows. anyway, I dont know if i have a real "stock" bin so if anyone has a 99 ss or z-28 lemme know.. i need your maps. However, when i log my LTFTs they are between +9 and +21.. they jump all over the place.. if i average them its like +17 or +18.. all over the map. Anyone have any clue what could be causing this?? Is it my o2s, vacuum leak, who knows??? i can send anyone a log file so you can see if you dont understand what i am trying to say. I dont know if its just the old tuning or a physical problem w/ my motor.. plz help. I cant tune unless i figure it out....

  2. #2
    Potential Tuner
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    May 2004
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    Re: Help!.. LTFTs out of control!!

    If you have another unmolested (stock) mass air housing, use it-and check your fuel trims again.

    I can email you a copy of my stock (99) bin file if you like.

  3. #3
    Potential Tuner
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    Re: Help!.. LTFTs out of control!!

    ok will do.

    Please send me your bin. my email is [email protected]

    Thanks.

  4. #4
    Senior Tuner
    Join Date
    Nov 2002
    Location
    Central Florida
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    2,503

    Re: Help!.. LTFTs out of control!!

    LTFTs should be consistent vs FTC (fuel trim cell).
    The LTFT is likely (almost certain) to be different
    in different regions (RPM, MAP) of operation. It
    usually tends to be richer at idle and leaner as
    you go up (my trims are like -10 at idle and -1
    at upper MAP, RPM).

    LT headers' effect on O2s is a problem for these
    cars, you may see the LTFTs drift around all the
    time as the O2s heat up, cool down, mess the
    mixture sensing around. No generally-accepted
    solution for that, that I've seen. Though header
    wrap might help you keep them hotter and more
    satisfied, have seen no before / after reports of
    anyone who's taken me up on that suggestion.

    And do inspect the MAF for buggery... preinstalled
    Hype-Tech is one of the seven warning signs the
    previous owner was a dumb-ass

  5. #5
    Tuner in Training
    Join Date
    Jun 2004
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    Johnston, RI
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    17

    Re: Help!.. LTFTs out of control!!

    Quote Originally Posted by jimmyblue
    (my trims are like -10 at idle and -1 at upper MAP, RPM).
    So it's rather normal to see much lower numbers in the upper left portion of the ltft histogram window while the rest of the chart is right in line?