VE tune changed drastically when MAF re-enabled?
03-13-2009, 04:13 PM
#1
VE tune changed drastically when MAF re-enabled?
I'm using HPTuners.
Vehicle is 2002 Silverado 5.3.
Following one of the many similar suggestions online regarding VE tuning, I first set MAF fail frequency to 0, made HIGH and LOW octane timing tables reflect the same timing, then using VCM Controls RESET fuel trims.
I datalogged for roughly 30 minutes each time. (3 times so far).
After 3rd time of making slight tune changes and reflashing pcm, my LTFT's were all between 0 and 3, which I "thought" was great.
I then set MAF fail frequency back to stock 13500 Mhz (I believe it was), and reset fuel trims once more. Just for the heck of it, I datalogged another 20+ minute drive and a LOT of my LTFT's are now ranging anywhere from 8-18, averaging about 13 in most lower rpm cells.
Why did my LTFT's change so dramatically after putting the MAF back into the mix?
Did I miss something, or do something wrong?
Just when I thought I was finally getting somewhere, I got knocked back 3 steps, lol...
Thanks for any help, ideas, or insight.
Vehicle is 2002 Silverado 5.3.
Following one of the many similar suggestions online regarding VE tuning, I first set MAF fail frequency to 0, made HIGH and LOW octane timing tables reflect the same timing, then using VCM Controls RESET fuel trims.
I datalogged for roughly 30 minutes each time. (3 times so far).
After 3rd time of making slight tune changes and reflashing pcm, my LTFT's were all between 0 and 3, which I "thought" was great.
I then set MAF fail frequency back to stock 13500 Mhz (I believe it was), and reset fuel trims once more. Just for the heck of it, I datalogged another 20+ minute drive and a LOT of my LTFT's are now ranging anywhere from 8-18, averaging about 13 in most lower rpm cells.
Why did my LTFT's change so dramatically after putting the MAF back into the mix?
Did I miss something, or do something wrong?
Just when I thought I was finally getting somewhere, I got knocked back 3 steps, lol...
Thanks for any help, ideas, or insight.
CRAP...I thought I was done...
As far as my truck goes anyways.
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03-13-2009, 05:02 PM
#10
TECH Junkie
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Yeah, I moved like two hours away. But it seems quite a bit colder here in lubbock compared to Midland. And I havent done any VE tuning sense that of last summer. I AM running COS 3 and I DO have some good VE multipliers set up to compensate for IAT changes, and they seem to be working.