Temperature Swing = Large LTFT Swing?
 

Had a strange thing occur today.

Car: 14 BRZ 6MT
Mods: Only the OFT on 2.0 EL E85 map

Last drove the car when it was probably mid to low 80's out. LTFT's were 0.78 around idle and not more than 1-2% everywhere else.

Started it this morning at 68 degrees and it let out a couple pops out the exhaust and then settled into a solid idle. At idle the LTFT's are now around +13%, but not under normal driving. 2nd Start was a bit better, and now as it's warming up and I'm driving around more, it's slowly down to 10%. But it's ONLY at idle. Going down the road it's only 2-3% LTFT.

Is a +-20 degree swing enough to surprise the car?

Nothing to worry about and totally normal. LTFT will move around quite a bit during cruise and partial load, depending on conditions. LTFT at idle aren't very important just as long as they are maxed out and you are achieving the desired AFR.

Thanks for the quick response as usual Shiv!

Is the popping/ rough start just a product of temperature swing and E85?

That's typical of E85 during cold start. It can be tuned out somewhat through custom tuning but it's a long process and most people just deal with it for the first few seconds of start-up :)

Awesome thanks!

Gotta say the car seems to run better the more tanks you put through it on E85.

Latest log:

http://datazap.me/u/joneze93tsi/e85v...ata=1-6-8-9-12

Car feels great!