I threw 2 CELs the other day and fixed 'em and wanted to reset the CEL light... so I tried to do it by removing the negative terminal on the battery, but it wouldn't come off for the life of me... so I went the second route and unplugged all 4 cables on my UTEC, waited 5 min, replugged 'em, let the car idle for 5 min, turned it off, turned it on, drove around for a night for over 130 miles (had to go places)... and here's what I've seemed to notice...

-Before reset, I got average of 11mpg - 14mpg, usually 12mpg.
-After reset, I got 19mpg, and today, it's looking to be around 18mpg
-Car's driveability seems much better... less spurting @ half-throttle in boost
-Car never stalls rolling in neutral (VTA BOV), before reset it would stall at least once a day rolling in neutral (had BOV recirc'n before reset, made it VTA and never reset the UTEC 'til now)
-Car *feels* a little slower (emphasis on "feels", no actual proof)

So my question is, what happens when you unplug all 4 cables on the UTEC for 5 min? Is my ECU slowly relearning stuff? If so, how long will it take? Any and all info would help greatly!

 

Yes, the ECU is relearning from being reset.. usually 3-5 full drive cycles will bring it back to normal.. Anyway, the UTEC's configuration hasn't changed, so your open loop tuning is the same, what your experiencing is your closed loop and part throttle drivability learning its long term fuel trims again..

 

Will my car return to how it felt before (sputtering in partial-throttle boost, stalling in neutral rolling w/ VTA BOV, etc.)? Or will it relearn to the way it is now, with the improved driveability staying? Will it be just as fast as it was before? I dyno this Saturday... hope it's back to normal by then...

 

Well, sputtering and stalling will come back if your using a VTA BOV, can't really avoid that.. I'm actually surprised it isn't worse at the moment..

It'll probably relearn and be a little better than it was before, but most of your drivability problems are likely due to using a VTA blowoff valve..

that is assuming you have a VTA Bov, or are you just comparing it to one?? LOL

Sputtering could be a tuning thing too, as you transition to open loop fuel control from closed loop ECU control.. But most of what your describing are a combination of the stock ECU getting "Upset" by misreads in the MAF due to non-recirculation..