+15 ltft iat idle
06-05-2006, 05:53 PM
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+15 ltft iat idle I have done some searching, but nothing specific to my issue:
I have tuned my LTFT's to around -4 to 0 using the maf calibration (airflow vrs frequency) table, the only one that will not come down is idle at 0 mph, these stay at about +15.
I have already tried x .90 my 400 and 800 VE columns twice, still the ltfts are way too high. Any ideas?
Does decreasing the VE richen or lean the mixture?
I have tuned my LTFT's to around -4 to 0 using the maf calibration (airflow vrs frequency) table, the only one that will not come down is idle at 0 mph, these stay at about +15.
I have already tried x .90 my 400 and 800 VE columns twice, still the ltfts are way too high. Any ideas?
Does decreasing the VE richen or lean the mixture?
06-05-2006, 06:02 PM
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Decreasing the VE leans out the mixture. A majority of the idle fueling comes from the VE...the rest from the MAF. Get the VE closer and tweak with the MAF.
06-05-2006, 06:06 PM
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Oh crap, so if my ltft's are positive, the pcm thinks its lean and increases ltft's to compinsate, so I need to increase my ve table to richen it. Therfore bringing my ltft's down. So I need to multiply by 1.10 to increase it. ok, I will try that, thanks!
06-05-2006, 06:10 PM
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your immediate crank..when you car has not been run is OPEN LOOP, your VE TABLE controls that. if your LTFT's are positive then you need to add fuel so it doesn't have to
06-05-2006, 06:53 PM
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Originally Posted by ZL1Killa
your immediate crank..when you car has not been run is OPEN LOOP, your VE TABLE controls that. if your LTFT's are positive then you need to add fuel so it doesn't have to
Don't guess with your VE Kevin. Read up on SD tuning. Turn off the MAF, copy the high spark to low spark, and drive around for a bit. Log LTFTs_vs_RPM_vs_MAP and STFTs_vs_RPM_vs_MAP just as they appear in the tuner program. Then, make your corrections based on what you see there. Don't guess.
