Fuel trim ?'s

[EROK006]

I am trying to tune my 91 talon with a pocket logger. I can't figure out why my fuel trims won't ever change no matter what I adjust on my VPC. they stay at high 81% mid 92% and low 81%. My O2 voltage changes but not these. I tried resetting my computer and that just made the all go to 99% and they've stayed like that for a couple of days. I thought these were supposed to change?

 

[NJGSX96]

resetting the ECU sets them back to 100% and then from there they relearn and will eventually go back to where they were at. They are basically saying that you are running rich. What is your Gain knob set at?

 

[EROK006]

I've adjusted it all over the place right now it's at about 1 o'clock. But no matter where I set it the trims won't change.

 

[NJGSX96]

Put it at around 7 o'clock. That is full lean. Then go find find a long road and go a constant speed at a set rpm. DO that for 2K, 3K, and 4K, preferably in 3rd gear if possible. You'll notice your fuel trims will begin to change. It isn't instantaneous. It takes 5 seconds of a constant condition to have them change. Keep your foot slightly on the gas. Do not coast. This is when the FT will change. FT are not changed or set during coasting and WOT.

Once you have them set, go WOT to see if the new setting has any adverse affects at full throttle. If so, richen or lean the gain if necessary. Chnaces are you'll be set around 8-11 o'clcok when all is said and done.

What is your Response at?

 

[EROK006]

Response is almost all the way up, maybe one click from full.