Anybody else have this problem? My ltft goes nuts if I turn on the AC and let the car idle for more than 5 Mins. Im talking about my ltft going from 7 at idle to near 18! It only does this with the ac on.

It also made my ltft go from 4 (cruising) to 8-10. Any ideas?

If it helps, its been ungodly hot the past 2 months (100+ and humid) wherareas I got tuned on a nice 80* day.

When I turn off the AC it takes a while for the trims to return to normal. (Hours of driving)

 

I have the same exact problem.
I'm sitting at like ~12 LTFT with use of A/C when it's usually around 5, I forget which side of the spectrum.

 

so you're saying you're surprised that it being hot and you loading the motor more is going to change fuel requirements?

thats why you have those trims to account for load differences and atmospheric conditions...

 

I don't know everything. Lol. Couldn't find anything searching.

 

if we didnt have fuel trims we'd be going back to the old carb days of constantly changing jets... you'd have to change tunes for morning drive, mid day drive and night drives otherwise if you wanted it spot on all the time. the beauty of these ECU's is they monitor everything and adjust for you.

 

It sounds like he needs to log with the A/C on and get it tuned for that condition too. Trims isn't fueling, it's fueling with relation to what's expected by the ECU/tune. If it was fueling, it'd skyrocket every time we hit the gas.