Bad to put WIDEBAND in downstream 02 spot on xpipe?

[86buick1]

Collecting readings almost immediately after collector. Can't get the gauge to read right.

Even at WOT under PE the gauge hovered around 14.6. Obviously not safe. BUT my LTFT were pulling OUT fuel throughout my whole table. I have my open loop EQ ratios set up right.
I picked up no KR under any circumstance, except for about 1.5 degrees around 80 KPA at 1600 (must have stabbed the gas).

So I know no detonation, and the car definitely smells like fuel. What gives? I think its a bad sensor. Very aggravating. Brand new AEM 30-4110 kit with a Bosch 4.9 LSU.

I even set up my PE settings to engage PE at 15+ map and anything over 20% tps. Same thing. I KNOW it would be running PIG rich around those areas.

I know it doesn't mean much but when going into PE 02s are 900 and 951 MV respectively.

[blindsquirrel]

Is the WB downstream of a functioning catalytic converter?

[86buick1]

No cats. I have a true dual system on a 2000 Transam with an X pipe. It is installed on a bung literally right after the header collector.

[5FDP]

Put the wideband in the front o2 sensor hole and see if it reads better. If it does, then something is up with the spot after the collector. But if it doesn't change then I'd say the sensor is faulty.

I'd disable LTFT to be honest. Just have STFT working and have the airflow model dialed in for stoich and power enrichment.

[86buick1]

Thanks, was going to try that tonight. I can't seem to get my STFT perfect, so I'd prefer to keep LTFT on. What is truly acceptable in terms of STFT values?

From what it seems to me the sensor actually WORKS until it gets hot. I was at around 130 degrees ECT and gave it throttle to get into PE (not high rpm, probably mid load) and I did see my AFR drop into the 11s. so it is doing something.
Only when the car gets to operating temperature it becomes retarded. No way it is running 14.6 at WOT, the thing would be pinging everywhere!....right?

[5FDP]

You can't really get STFT to be perfect, there are too many variables that change the numbers. If for the most part they stay under +/- 5-7% and are always on the move, it's doing a pretty good job at correcting the trims on the fly.

If you used the wideband to make an AFR or Lambda error, the short terms always end up pretty close to where I need them.

[86buick1]

I tried doing that, but can't get my histogram to work. Do you have your own personal way of doing this?
I tried the afr error vs MAP and RPM, but wont do a darn thing.

[5FDP]

Well, it has to be done in open loop with all fuel trims and closed loop disables. The MAF has to be failed if calibrating the VE and or vise versa if you are doing the MAF curve.

The VCM scanner section has write ups in the stickys if you think you are making your graphs wrong for logging your data.

[85K5Jake]

How is the sensor mounted? It needs to be angled with the head down somewhere around 15 degrees at least to work best.

[86buick1]

Figured it out guys. Wideband is NOT reading right. Took everything out, I got the sensor to full sweep ONE time. I thought cool! Just bad wiring. Nope. I had to keep unplugging the gauge for it to go full lean, then it would hover at stoich no matter what. When I'd hit it with brake cleaner it would go LEAN lol!
Buying a PLX kit with another bosch sensor sunday, crossing my fingers.

If I scaled my maf with everything enabled included LTFT and both tables, is this bad? Car seems to run fine and trims are pretty good. Just curious.

[86buick1]

Anyone?

[5FDP]

Yes, that is technically wrong.

If you tried to re-calibrate the MAF or VE with fuel trims and closed loop active using your wideband, all that data would have been skewed.

Go back over it with everything disabled and see how far off the wideband error is and clean it up as needed. Then work on WOT if you need too.