I recently made some changes to my high and low octane timing tables, along with my base spark tables. Before I made changes, my LTFT and STFT were in the 0 to -2 range. Well today I went and put the car in SD mode ie:MAF set to 0, LTFT=off, disabled PE and reset fuel trims. I went for a drive and could not believe my STFT were -12.

Could this happen from making changes to my timng tables?


If yes...do I have to start all over again with VE tuning? ie:start with LTFT and do the 100 mile re-learn?


Or should I retune my LTFT anyway???

Thanks,
Jason

 

changes in timing will cause it. it shouldnt take too long to retune the ve though.

 

Should I just retune just the STFT? Or should I do both, LTFT and STFT??

Thanks Nino!

 

Id do your ltft's till they're +/-10 either way and then do stft's. Im not at home otherwise Id send you an excel file Marcin sent me that helps out alot for quickly tuning the ve.

 

while we are on this topic, surely you would want timing to be set at the point where the maximum fueling occurs at commanded afr. I would assume that cylinder pressure is maximised with maximum fueling, so to retune and remove fueling will reduce power. maybe that is a bit generalist but as long as timing combusts all the fuel efficiently I can't see why retuning with less fuel is good for power?

 

Hey Nino, Rob or anyone...

Are you guys disabling PE mode when tuning for LTFT?

 

no, just keeping my throttle under wot

 

Why not? This way...there is no chance of going into PE?

 

im usually in higher gears or my tps isnt at the percentage it needs to be in order to be considered by PE. I could disable it, but im lazy

 

I think to be on the safe side...I will disable it. Just in case my right foot gets an itch.


How bout them COWBOYS!!!!!!!!!!!! YEAH Buddy!

 

Yes, I disable it while logging/tuning VE - if you enter PE it will throw the numbers off, depending on how you are tuning VE...

There are different schools of thought on this - some folks set the OLFA table to 1.0 and tune VE exclusively in PE (set PE RPM to 0 and MAP kpa to 0 so it's always in PE). I chose the other route, stay out of PE to tune VE and use PE the way I believe it was intended, as a 'power enrichment' over the base table for high RPM/load/WOT.

Rob (Bad30th)

 

me too (with Bad30th)