o2 sensors are staying above 800 constantly
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o2 sensors are staying above 800 constantly
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?
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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.
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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?
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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.
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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.
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Originally Posted by YellowToy/A
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.
Last edited by black_ws6; 06-14-2005 at 05:47 PM.
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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.
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Originally Posted by YellowToy/A
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.
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Originally Posted by YellowToy/A
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.
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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
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
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Originally Posted by YellowToy/A
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.
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Originally Posted by 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
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
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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
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
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Originally Posted by Black02SS
Do you have a ses light on by chance?
Horist, the files are on the way.