Quote:
Originally Posted by Tor
Can you help me understand the fuel trims conceptually (or point me to a place where it is explained)? If the car runs slightly lean below 5000 rpm, why am I seeing negative fuel trim? Wouldn't it make more sense it was adding fuel if it runs lean?
I did the MAF scaling logs when it was pretty cold here, only 13-16 deg C. The log above was done at 24 deg C. Was it a bad idea to scale at those fairly low temperatures? The fuel trims here are probably not so accurate since it didn't have enough learn.
Thanks again!
|
Hmm.. I'm pretty sure OP of this thread explains how fuel trims and MAF scale works..
The way the stock IAT compensation is set up it tends to run richer in cooler weather but leaner when IAT get warmer for a given value on the MAF scale. So, if you calibrated your maf scale using information taken with low IAT values the scale will tend to be "lean," meaning the MAF scale values will tend to be lower. When this lower valued scale is used in warmer conditions your computer will add even more fuel by increasing fuel trims to compensate for the lean condition in CL.
http://datazap.me/u/tor/stock-a00g-m...2813&mark=2671
Looking at this pull in your log, your commanded AFR and AFR reading also look pretty strange. Towards redline the Commanded AFR goes as rich as 10.8:1 while the AFRs only goes up to 12.13:1 even with +5% LTFT. This tells me your maf scale is quite a bit off. Are you running FI or NA? What are you using to flash your rom and for data logging?