who's got a datalogger? -> LTFT at idle
Feb 15, 2005, 01:54 PM
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who's got a datalogger? -> LTFT at idle
so i've noticed that LTFT at idle is different than when the car is moving or on load. moving the BISS screw seems to adjust it. could adjusting the BISS screw so that LTFT is 0 at idle mean that the IAC is adjusted correctly and in range? why i ask is because who really has a factory scan tool($$$) to adjust the BISS when the SAS screw has been messed with.
Feb 16, 2005, 11:46 AM
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Fuel trims are going to adjust at different RPMS and load. What do your short terms say? Are you still on stock injectors?
This really for an Evo, but the basics are the same;
http://www.evotuners.net/forums/showthread.php?t=315
This really for an Evo, but the basics are the same;
http://www.evotuners.net/forums/showthread.php?t=315
Feb 16, 2005, 01:12 PM
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STFT are around 0 with maybe only a +/- 3% deviation. stock fuel injectors but raised fuel pressure. doesn't really matter since i've observed this at stock as well.
LTFT value doesn't change from low rpm to high rpm while STFT changes constantly. LTFT value doesn't change until a large enough change in STFT is seen over a period of time. BUT, when the car is at idle/stop/throttle closed, LTFT changes to a different value that can be modified by adjusting the BISS screw. So there are 2 LTFT values present. one at idle, and one with throttle position greater than 0%. Since the value i'm talking about only changes at idle from adjusting the BISS screw, and the BISS screw is useless at throttle greater than closed, this LTFT value only has to deal with idle. with the only intake parts related to idle are the IAC and BISS screw, the LTFT value at idle would only seem to correspond to the IAC since the BISS adjustment is static/constant.
just looking for any ideas behind this. oh, and evotuners is down at the moment, but i'll read it when it opens back up. thanks.
LTFT value doesn't change from low rpm to high rpm while STFT changes constantly. LTFT value doesn't change until a large enough change in STFT is seen over a period of time. BUT, when the car is at idle/stop/throttle closed, LTFT changes to a different value that can be modified by adjusting the BISS screw. So there are 2 LTFT values present. one at idle, and one with throttle position greater than 0%. Since the value i'm talking about only changes at idle from adjusting the BISS screw, and the BISS screw is useless at throttle greater than closed, this LTFT value only has to deal with idle. with the only intake parts related to idle are the IAC and BISS screw, the LTFT value at idle would only seem to correspond to the IAC since the BISS adjustment is static/constant.
just looking for any ideas behind this. oh, and evotuners is down at the moment, but i'll read it when it opens back up. thanks.
Last edited by rhyzin; Feb 16, 2005 at 02:41 PM.
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