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Thread: Short term fuel trim question?

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    Question Short term fuel trim question?

    Hello everyone, i did some data logging on my 03 ford harley davidson, my mods are pulley and programer making a total of 10-11 boost, and i saw that the Short term fuel trim shows min. -10.94 and max 25.78, i did a WOT run, i thought it should be closer at 0, what do you guys think? are the number ok?

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    Oh sorry, its on BANK 1

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    what is bank 1 02sen
    Quote Originally Posted by tagman2 View Post
    Oh sorry, its on BANK 1

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    Your SHFT wants to be at or around 0 which is what your Long fuel trim controls over time. The PCM will watch your short fuel trim and bump up the long trims to get the short back to 0 but it takes time, learning. If theres a large enough instant vacuum leak for example, the long fuel trim wont be able to bring the short down to zero and set a code.

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    Quote Originally Posted by GRANTBP View Post
    what is bank 1 02sen
    Right side upstream O2 sensor. O2 11 is right side ahead of converter, 12 is right bank after the converter. 21 and 22 the other side.

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    Sorry for changing the subject, i filled up my gas tank with 87 octane, and my truck did not even ping, as im on 11 psi boost, so should i advance the timing? sorry im a noob at this stuff

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    Quote Originally Posted by Newman View Post
    Right side upstream O2 sensor. O2 11 is right side ahead of converter, 12 is right bank after the converter. 21 and 22 the other side.

    do i need to check for vac leek also or replace all 4 02 sensors

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    Short term fuel trim question?

    O2 sensors are fine, they are doing their job.

    The problem is more likely a vacuum leak.
    2002 DSG HD #09617 NHTOC Truck of the month November 2012
    Ported eaton/plenum/tb, 6lb lower, SCT BA-2600 MAF, OBX longtubes, JLP intake, FTVB, L-spec bilsteins, Hotchkis TVS, 22" replicas. Tuned by Ray McClelland of FTK

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    can't find it will look some more

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    Quote Originally Posted by tagman2 View Post
    Sorry for changing the subject, i filled up my gas tank with 87 octane, and my truck did not even ping, as im on 11 psi boost, so should i advance the timing? sorry im a noob at this stuff
    Get the 87 out of your truck . Just because you can't hear it ping doesn't mean you are not experiencing detonation.

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    Quote Originally Posted by tagman2 View Post
    Sorry for changing the subject, i filled up my gas tank with 87 octane sorry im a noob at this stuff
    87 Octane? ... FAIL!!

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    Quote Originally Posted by musturbo View Post
    Get the 87 out of your truck .
    + 1 Bazillion!

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    Quote Originally Posted by Blind View Post
    O2 sensors are fine, they are doing their job.

    The problem is more likely a vacuum leak.
    +1. Another possibility is a miss. Because O2 sensors only see oxygen not unburned fuel, they see the oxygen left behind in an unburned air/fuel mixture.

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    Quote Originally Posted by Newman View Post
    +1. Another possibility is a miss. Because O2 sensors only see oxygen not unburned fuel, they see the oxygen left behind in an unburned air/fuel mixture.
    i have checked did the carb cleaner test nothing cleaned the map nothing i'am at the point to take it to the shop this is running me hot!!!
    Last edited by GRANTBP; 11-26-2012 at 09:06 PM.

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    Quote Originally Posted by musturbo View Post
    Get the 87 out of your truck . Just because you can't hear it ping doesn't mean you are not experiencing detonation.
    This man speaks the truth. I know what detonation sounds like after building and racing cars for 55 years, this mod motor is a real puzzlement, detonation is a pistol to hear.

    Mike

    ************************CLICK TO VISIT MAD'S SITE************************


    '02, 32V, 5.4L #001, 14psi Whipple and a few other mods. 640 rwhp, 610 tq. CA Smog legal

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