Quote Originally Posted by 91parkave View Post
No need to unplug your 02 to my knowledge. Unless its a weird "3800ism" that needs to be done . remember open loop does not use fuel trims.(some gm os will allow this but most dont)so you can't tune maf via fueltrims in open loop. Once you hit pe or wot that will freeze trims and run in open loop at the Afr you set.

As for smoothing I don't believe in it. I like us I g the exact numbers the scanner tells me.
Gotcha!

I could have sworn "darkhorizon" stated that he tunes afr/wot in open loop. Due to the fact that in closed loop you are "tuning" your narrowbands as the pcm sees the trims. If all the trims are spot on then there should be no worry? But maybe its a preference thing?

At the beginning of this thread I afr/wot tuned with it plugged in then with it unplugged. The afr was spot on each time. I also can't say anything about "pro tunes" on the dyno. I don't know if they force open loop.

At least I can start on the maf tune and get to the afr/wot portion after. As I did it backwards.