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.

 

You need to tune the MAF table now... Tuning just the VE table is only half of the equation...

 

CRAP...I thought I was done...

 

You are, half way done that is...

 

Just be happy if you are not as picky and **** as I am otherwise you will never be done. As far as my truck goes anyways.

 

just run OLSD, now your done lol.

 

LOL...hmmmm...

 

Ive had it NA, now turbo like that for around a year. I moved last August and still havent touched the VE.....

 

By saying "haven't touched it", I assume you mean that since it was originally tuned, you haven't changed VE tune at all?

Mine seemed to run quite well in OLSD actually.

 

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.