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BMW 3-Series (E90 E92) Forum
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Negative LTFT at Idle
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02-10-2021, 07:03 PM | #1 |
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I have been noticing my LTFT at idle has been pretty low around -9 to -10%. I reset lamba adaptations and was able to log it to show it going from 0% down to -10% at idle. when I apply light throttle the LTFT does go back up towards 0%. Shouldn't LTFT at idle be close and remain at 0%? what could cause the LTFT to slowly drop to these levels?
here is the log https://datazap.me/u/nrigs/idle-nega...18&zoom=38-446 Car is custom tuned by Steven at Wedge
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Current: 2011 BMW 335xi | Wedge Tuned | Meth | VRSF DP | VRSF 5" Intercooler | VRSF Chargepipe | BMS Intake | xHP Stg 3
Totaled:2014 Audi A4 CTS K04 APR Tuned |
02-12-2021, 10:05 AM | #2 |
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Incorrect fueling at idle is the short and simple answer.
But is this really a problem? No. Hell, I知 sitting in my own car with ~315 revisions to my tune right now and I知 getting +12% LTFT at idle. Idle does some weird stuff - fueling is different, ignition is different, and everything is running on closed loops to try and make idle nice and happy. If you want to see something really wild, look at your ignition timings at idle As long as your driveability is good, you池e not seeing ignition corrections, and boost/load is under control, ya good. |
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02-12-2021, 10:24 AM | #3 | |
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Quote:
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Current: 2011 BMW 335xi | Wedge Tuned | Meth | VRSF DP | VRSF 5" Intercooler | VRSF Chargepipe | BMS Intake | xHP Stg 3
Totaled:2014 Audi A4 CTS K04 APR Tuned |
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02-12-2021, 10:25 AM | #4 |
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I sent these logs to my tuner to see what he thinks and to see if he can tune this out.
Cold Start Idle - High Fuel Pressure at 90 seconds https://datazap.me/u/nrigs/high-fuel...-11-15&solo=15 Warm Start Idle - LTFT drops to -9% (Other times I have seen idle around -11%) https://datazap.me/u/nrigs/stage-2-i...=11-15&solo=15 Warm Start Idle Stage 2 OTS map https://datazap.me/u/nrigs/stage-2-i...g=0&data=11-15
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Current: 2011 BMW 335xi | Wedge Tuned | Meth | VRSF DP | VRSF 5" Intercooler | VRSF Chargepipe | BMS Intake | xHP Stg 3
Totaled:2014 Audi A4 CTS K04 APR Tuned |
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09-24-2024, 11:40 PM | #5 | |
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