VE LTFT tuning after Longtubes

Billdog350 · 06-09-2006, 09:52 AM

Guys, I've been tuning the VE tables (In SD mode with MAF disabled) by datalogging the LTFT pids as well as MAF and RPM. I have reduced my LTFT from 10-15+ down to 5 so far....aiming for 0 or -3 when I'm done.

My question is: has anyone else done this and have they had to SIGNIFICANTLY alter their VE table (adding more than 10 to the existing values) to get things in line? I'm wondering why the logging is taking a while to respond. I drive it for 20-30 miles after each tune so it should be adjusting to the new trims. Also, I have been copying the main table to the backup table just in case that is affecting it. I've already added about 10-15 to all of the cells and I would have expected to be in the - range by now...

Billdog350 · 06-09-2006, 04:23 PM

Found the answer from a fellow tuner.

You're supposed to be logging your STFT (Short term fuel trims) and making changes by PERCENTAGE...not numbers.

EG if your STFT's are high by 10 across the board, increase your table by 10% and you'll be much closer!

The car is now tuned to +-2% for the whole table which is better than I thought I'd be able to get....now time for MAF and PE tuning! Once my LC-1 comes in I'll be good to go!

Darkness · 06-10-2006, 04:47 PM

What software do you have? I have EFILive and an LC-1 and need to get my LTFT's closer to 0 as well but I'm still too much of a newb to do it! lol My wot is good though, just the part throttle cruise.

Billdog350 · 06-16-2006, 01:25 PM

tune your STFT's first. Log the STFT's vs MAP vs RPM.....look for large negatives or positives. Here is a great document on tuning basics.
http://www.wnyym.com/newbie/tuning_new.htm
http://www.ls1tech.com/forums/showthread.php?t=287094