pHEnomIC

iTrader: (14)

I tuned my car off of a wideband located right after one of the nbs. Torquer v3, boltons, etc. I grounded my wideband on the computer so i dont think there is a voltage offset or anything like that, but my wb a/f ratio was very low at all conditions (running maf mode).

I just went into closed loop to see if it could save me some gas mileage and my fuel trims were up to -15% in areas hit when idle and light throttle. Everywhere else, they seem to agree. I think the NBs might be correct because my gas mileage was horrible.

Is the wideband misreading low load due to the cams properties?

Dragman

I would never tune a car with a NB o2 sensor. need to see if wideband is correct though. Hard to tune if wideband off.

pHEnomIC

iTrader: (14)

Whats a good way to see if wideband is correct? I really havent found a good way.

OK i trimmed it a bit in that area because i think it was running rich there. Runs pretty good right now, ltfts are actually pretty low and wideband is about 5-6% different. Its running pretty good but honestly i think it ran a little better in open loop.

vaticano

iTrader: (8)

A wide band should read 20.9% o2 in the open air. Thus the name open air calibration. If you don't want to remove it from the car you can rev up the engine and shut it off while at 2-3K RPM. Shutting it down will shut off the injectgors and blow out all the exhaust gasses and fill the exhaust with fresh air.

jimmyblue

iTrader: (11)

You can still have substantial ground offset, depending
on how heater current is routed through the wideband.
The only success I've had in eliminating it, is building
a floating-supply instrumentation amplifier. With it I
have about 0.1 AFR skew (looks random) and without
I had over 0.5 AFR consistent offset. There's just too
much crap going on in some of these units (sharing
signal and heater ground, etc.) to guess and the
skew can vary with the weather and driving (EGT).

pHEnomIC

iTrader: (14)

Sheesh how hard is it for them to build a precision device, seems like a lot of these things have issues.

So basically i have done the following:
Tuned all the settings how i wanted them > tuned VE off of wideband (till consistently low a/f error)>generated a maf table in excel off of the speed density calculated air flow>used the wideband to tweak the maf table slightly>put it in closed loop and used some ltfts to correct my maf table a bit (mostly in the idle range and light throttle, none really elsewhere).

Now it seems like its running great, ltfts are minimal, seems a little rough before its warmed up but Im gonna do a cold idle scan. WOT fueling is exactly what i call for and the computer seems to be trimming and running just fine.

Can I call it a day and say my tune is done?