WOT O2 Question
06-29-2009, 01:32 PM
#1
WOT O2 Question Car is a bone stock 2000 formula M6. While scanning, I noticed some knock during WOT runs. The O2s are also behaving oddly. Bank2 Sensor 1 behaves as normal during WOT; it flatlines around 860mV. Bank1 Sensor 1 does not. It may flatline briefly, but then begins oscillating as it would under part throttle.
What is causing the behavior? Is it something to worry about?
What is causing the behavior? Is it something to worry about?
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06-30-2009, 04:26 PM
#12
Is that true? The switching or oscillation that you see under part throttle scanning is the computer adjusting fueling to maintain 14.7:1. If I was running lean at WOT, I shouldn't I still see a flat line? The oscillation is a result of the computer adding or subtracting fuel, which shouldn't happen at WOT since WOT references MAF and PE tables?
06-30-2009, 04:51 PM
#13
It doesn't really look like it's switching it's just not a stable line. If you don't have a wideband to actually see what you're running at then try making a WOT pass shutting the car off as soon as you let off the gas and pull the plugs see what they look like. Maybe you have a bad/partially clogged injector.
06-30-2009, 04:53 PM
#14
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can you get injector pulswidth values on that particular log? anyway, banks 1 and 2 should be very close to each other during the times that you encountered the low o2 reading. for example on my data log for wot banks 1,2 are around 17.xxx ms, injector duty cycle should also be similar. the fact that you are getting kr during wot is a clear sign that you may be a bit lean. my na wot runs always display about .900mv., .880mv to .900mv is very close to 13.1 on for my wot runs. i would venture to say that .860mv is probably to lean. since your pcm has never been flashed, and the 02 ind. are accurate, then perhaps you are loosing fuel press. or maybe an injector is failing. maybe it's due to the seamfoam treatment.
06-30-2009, 05:35 PM
#15
Look at the log that is posted.
All noted frames are at 100% TPS.
frames 1372 to 1387 B1 are lean enough that the O2 switches
frames 1417 to 1434 B1 are lean enough that the O2 switches
frames 2040 to 2052 B1 O2 just sits on the floor around 30-50mV and the subsequent frames show the same...
and at that point I am not looking through more of the log; it is very lean. The other O2 reads low 800mV's, and though we cannot take an AFR value from it, somewhere in the low-mid 800mV the O2s typically break low all at once...
All noted frames are at 100% TPS.
frames 1372 to 1387 B1 are lean enough that the O2 switches
frames 1417 to 1434 B1 are lean enough that the O2 switches
frames 2040 to 2052 B1 O2 just sits on the floor around 30-50mV and the subsequent frames show the same...
and at that point I am not looking through more of the log; it is very lean. The other O2 reads low 800mV's, and though we cannot take an AFR value from it, somewhere in the low-mid 800mV the O2s typically break low all at once...
07-01-2009, 09:27 AM
#18
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before you go wot again, i would log idle and then part t. runs from say 20%tps to 50%tps and see how bank 1,2 parameters compare, frame by frame. if you have tuning capabilities take out 3 degs. of timing in the high load sections for safety until you filgure it out. it would not hurt to ck. all the injector elec. connectors.
07-01-2009, 02:23 PM
#19
before you go wot again, i would log idle and then part t. runs from say 20%tps to 50%tps and see how bank 1,2 parameters compare, frame by frame. if you have tuning capabilities take out 3 degs. of timing in the high load sections for safety until you filgure it out. it would not hurt to ck. all the injector elec. connectors.
07-01-2009, 09:14 PM
#20
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if you do not go into pe, then your trims should be close to each other. if for example the suspect o2 sensor is in deed erratic you[ll see it hang or pause very low or high compared to the opposite side. in closed loop it should oscillate between say .400 and .600 or so, i'm not 100% sure on the normal low and high. more importantly if you do not get kr and the engine is behaving normally, there is still a good chance you are loosing fuel on the suspect side at wot.