lo throttle with afc

v8killerr1 · 09-14-2004, 08:18 PM

Ok, i've read the tuning guide and searched and I'm kind of confused. For the lo throttle settings do you want the LFLT to be zero or do you want to add the short and long together to equal zero? Also, do you want to free rev and get your base settings then take a drive and get the fuel trims zero while driving or just use the settings that you free reved with. thanks

kpt4321 · 09-14-2004, 10:35 PM

Add the STFT and LTFT.

You can free-rev and then drive, or just drive. I just drive.

v8killerr1 · 09-15-2004, 09:32 PM

thanks for the info some people were saying only tune for the ltft so i was a little confused. The car is a crap load faster after i've tuned the lo and hi.

kpt4321 · 09-15-2004, 10:50 PM

The LTFT is simply the saved trends from the STFT. If the STFT is rich (or lean, or whatever) for a certain amount of time, then the ECU starts changing the LTFT, and saves it for future use.

In addition, when figuring the injector pulsewidth, the ECU uses the LTFT and the STFT. This means you need to take both into account.

You could get the car tuned using the LTFT only; you would need to tune the LTFT down, drive the car a bunch, adjust based on the LTFT, and repeat. Watching the STFT allows you to predict where the LTFT is going to go in the future, and that way you can simply catch it before it gets too far away from where you want it.