[Jack44]

Probably been brought up before...

Would like to know why, old age made me forget is my excuse, we tune with the AFC2 and the like, to the LFT1 numbers...

A Dyno Shop near me said they tune to the SFT1 numbers...

So why Long Term rather than Short Term...Just seems that you'd want to tune to what's happening at 'that time'...

 

[BoogieQ]

you tune to your ltft's because once you go WOT the computer locks in the last good value of the ltft reading and then runs off of o2's. SO, from my understanding, if your car is constantly pulling fuel at idle/cruiz do to being to rich then you go WOT it's going to 'freak' and try to add fuel but once it reaches WOT 8K+ Maff hz it's locked in and might be at too low of a figure and will run lean at the top.

I may be wrong or using the wrong expressions but I found I had to use the afc to tune ltft's more lean at idle/cruiz and at 8K+ go into the 103% range and we don't run into a wot lean problem anymore.

 

[John F]

Your LTFT's are derived from the STFT's after a certain period of time. (not sure exactly how long)
So your LTFT are an average of your STFT.