Rear O2 impact?
Jun 17, 2010, 12:05 AM
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Rear O2 impact?
So I have removed the stock rear O2 sensor, and repalced it with a wideband. I found the thread on how to make the changes in ecuflash and add a resistor in the harness to turn off the CEL. My question is what is the impact on the car right now? With no signal from the rear O2 does the ecu add/subract fuel or anything to do with timing. I don't care if the CEL is on the bulb burned out anyway, I just check the DTC's every month or so, but I want to make sure it is not harming the car in anyway. Any input, thoughts or info would be great, thanks in advance.
Jun 17, 2010, 12:11 AM
#2
hmm, well this should not be an issue because the rear o2 sensor is used to make sure the cat is working correctly. There is actually an option in the tephra mod map that allows the emulation of what the front o2 sensor is reading to the rear o2 sensor, so one would think that the rear o2 sensors input in terms of ecu feedback is not important. Hope this helps!
Jun 17, 2010, 12:23 AM
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hmm, well this should not be an issue because the rear o2 sensor is used to make sure the cat is working correctly. There is actually an option in the tephra mod map that allows the emulation of what the front o2 sensor is reading to the rear o2 sensor, so one would think that the rear o2 sensors input in terms of ecu feedback is not important. Hope this helps!
. If you have any doubt , just weld a bung for the wideband o2 sensor on the downpipe 4 inches away from the cat. This way you get to keep all three sensors and no cels!
Jun 17, 2010, 11:57 AM
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Jun 17, 2010, 09:19 PM
#9
Why would the post cat o2 sensor be the one used for fuel trims?? Am I completely missing something?? I have been getting the p0420 about every two weeks or so. If this is affecting my fuel trim then I need to figure something out! Any advice would be good!
By the way I have a 3" Turbo back installed w/ high flow cat. Thanks guys!!
By the way I have a 3" Turbo back installed w/ high flow cat. Thanks guys!!
Jun 18, 2010, 07:55 AM
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wouldn’t surprise me at all it has an effect on a Mitsubishi.... i know for a fact that on my 04 STI when you disconnect the rear O2 the car will run about 1.0 AFR richer. best explanation i have been able to find is that the ECU uses the rear O2 to check the cat efficiency and fine tunes the fuel to keep the cat in its most efficient operating range.
Jun 18, 2010, 08:05 AM
#11
Or you could read all of the other threads that you got that information from....
It is only used to check catalytic efficiency, but disabling one of the periphery bits (that was originally thought to be a solution, and later found to not be) will cause the trims to stop adjusting.
It is only used to check catalytic efficiency, but disabling one of the periphery bits (that was originally thought to be a solution, and later found to not be) will cause the trims to stop adjusting.
