black_ws6

What would cause my 02 sensors to constantly read above 800? I looked at a log file from a friends car and his o2's constantly fluctuated between as low as 50 and up to 900 during highway crusing. The graph looks like a constant zig zag. Mine stay above 700 all the time. I think this is the cause of my poor gas mileage, but I have no idea what is causing it. Any ideas?

87GMC

One of my o2 is doing the same thing on pass side. I'm still running stock exhaust manifolds

SSpdDmon

iTrader: (10)

Might be a sign of a lazy O2 that's on its way out...

black_ws6

I already swapped in a different O2 in from a friends 02 Firehawk. Plus both of them are reading that way. I want to get this thing tuned, but I have to figure this out first.

YellowToy/A

iTrader: (1)

I think that your long term trims are off by more than the ECM wants. You are running rich. Poor gas mileage. Go get it tuned that should fix it. If you are looking at O2 volts, what are your fuel trims?

black_ws6

My LTFTs are in the +8 and +9 range in the upper left corner of the chart and mostly 0 and a +1 in the bottom right. With all of the 0's, I think I am not getting a good reading at WOT.

YellowToy/A

iTrader: (1)

What program are you using to look at this. I think that you need to use a strip chart to watch the fuel trims compared to the O2 volts If the fuel trims change and the O2 volts do not then you are not in closed loop control. Closed loop control is where the ECU uses the output of the O2 to control the air/fuel ratio.

black_ws6

I'm using HP tuners. I can post up a log file if that will help.

RedHardSupra

iTrader: (1)

swap the O2s and see if the 'lazyness' follows the swap. if it does, it's the O2, if it doesn't, something's wrong with your setup, or the connectors on that one side.

black_ws6

Here is the file.

YellowToy/A

iTrader: (1)

I looked at your log file. Your LT trim factors are always plus. They never take fuel away. I do not think that you logged the ST trim factors. The ECU does ST + LT = correction. I think your O2 are OK. I think that the ECM is in open loop all the time and u r running rich about 12.5 AIR/FUEL. U will need to find out y the ECM in in open loop. Have you changed anything with HPT? Run a log with ST TRIM factors and see what they look like.

black_ws6

I noticed that my ST's didn't log, but I didn't have them turned off. I just think something isn't right and they did not register, if that's possible.

YellowToy/A

iTrader: (1)

I have no idea. You might start a new thread with the " why am I in open loop and My st trims do not update.

black_ws6

I am ready to start a new thread called. For Sale: 2000 WS6.......

horist

Send me your .bin file (email below... ) and I'll take a look...

It looks like either you're open loop all the time (but in Open Loop I don't think the LTRIMs update ... unless those are saved... try clearning the fuel trims and relogging to see if they stay at 0 ... )

or you're in closed loop and your stoich commanded AFR is like 13.6:1 or something...

Add "Commanded AFR" to your PID list and rescan, this is in the scanner (remove fuel trim cell and add the low resolution Commanded AFR ... Fuel System -> Air Fuel Ratio Commanded (Low))

Scan the car again and let's see what the PCM is commanding... also send me your .bin and i'll check it out quickly

SSpdDmon

iTrader: (10)

Why would there be any STFT's if he's in open loop?? They are a correcting factor and there are no computer corrections (in general) to open loop. When I went into P/E or open loop watching the scanner on the Predator, the STFT's zero-ed out. So, he shouldn't see any (I wouldn't think) STFT's if his PCM is commanding open loop. Positive LTFT's can, however, add fuel to open loop operation depending on how positive they are (as a safety measure).

black_ws6

I'll send the bin when I get home from work. Thanks a ton!

YellowToy/A

iTrader: (1)

SSpdDmod

I should have said 0. I did not know that the ST could be 0 and the LTs could still update. There is still alot I do not KNOW.

Horist I think you could be right about the A/F being set to less that 14.4

Black02SS

iTrader: (36)

Do you have a ses light on by chance?

black_ws6

yes. I was getting p134, p135, and p155. That's why we swapped in a different O2 for bank1. I also had a O2 extension that had 2 cut wires, but they have been spliced back together. I am thinking I should just get a new extension and plan to.

Horist, the files are on the way.