fuel trims ok?
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From: Watertown, NY
fuel trims ok? SD was on, then when logging with MAF, LTFT's were all whacked. Anyway I did some corrections and my LTFT's are now between 0 and -5. Is this a good range or should I tighten it up more. It seems as though it is my idle that is causing it to go down to -5 because while idling my STFT's drop way down from -5 to -9.
Originally Posted by brad8266
SD was on, then when logging with MAF, LTFT's were all whacked. Anyway I did some corrections and my LTFT's are now between 0 and -5. Is this a good range or should I tighten it up more. It seems as though it is my idle that is causing it to go down to -5 because while idling my STFT's drop way down from -5 to -9.
Well were you tightening it up by adjusting the VE, the backup-VE, or the MAF table?
that answer will make all the difference.
My own suggestion is that when you are in SD mode, to NOT shoot for 14.7 AFR on your wideband, but something higher like 15.5 - 15.7 or about 7% less fuel in that block of the VE. There's really no reason to keep your warm idle at 14.7:1 besides to keep the emissions systems working within spec.
Originally Posted by brad8266
I tightened it up if the MAF table, everything seemed Ok in SD.
Keep in mind that when you activate the MAF again that you're also switching back to the main VE table instead of the backup table.
IMO between -1 and -5% LTFT's are great if you're running closed loop.
Sounds like you probably did the right thing to me.
