BEAMERGUY4EVER
07-14-2007, 04:18 PM
Well I finally got around to replacing my bad 02 sensor now that my tags have expired (procrastination bites me again! doh!) and it didn't fix my problem. I'm concerned it may be an issue with my used M3 exhaust. Here's the story...
I put 96+ M3 exhaust (headers back) on my 99 323iS, fit great, plugged the right side, put my 323iS 02 sensors on the left header and cat (I read on here a while a back that a couple guys did this exact thing with no issues whatsoever). Problem... I didn't run the post-cat sensor wire well, and it melted; check engine light came on. I only drove it for two days before this happened. BTW, it runs and sounds excellent, no issues except this 02 sensor.
I replaced the 02 sensor with one of the M3 post-cat 02 sensors that came with the used exhaust, not sure if they are the same or not? I never was able to get the check engine light to stay off, or to read from the bank 2 sensor at all (I have proscan OBDII software with an Elmscan interface). Reads fine from bank 1 sensor, gets lots of data. I figure, must be a bad 02 sensor, or maybe they are different for the M3. So I get a new 323iS post-cat 02 sensor and put it in yesterday.
Well I hook up the lappy and the new 02 sensor behaves exactly as the old M3 one did... Won't read with my scantool, and outputs 1.015V constant according to the logging with Proscan (this is only data it can read, there should be much more, and this voltage should be fluctuating constantly, as is the pre-cat sensor V output). I can't pass DEQ like this, of course, because my check engine light keeps coming back on with a bank 2 oxygen sensor error.
Potential causes:
1-New 02 sensor also bad? doubtful.
2-Catalytic converter no good? Maybe... but I would think it would still be able to read from sensor 2 even if cat was bad, wouldn't it?
3-When the wiring melted on the first sensor installed (above), it maybe shorted out something in the computer and now it cant read the sensor properly anymore? I have no idea if this could be possible or not.
4-Hooking the M3 sensor up to it was a bad idea, and maybe damaged the computer somehow? I don't think this is likely at all, but who knows.
5-Or maybe it just won't work like this, because my sensors are reading exhaust from 3 chambers now instead of all 6, and the computer is expecting a totally different range of info? But those other guys got it to work fine supposedly... were they telling the whole story?
Potential fixes:
1-Change post-cat 02 sensor over to the right (as in left/right) pipe and hope it starts reading something with that cat.
2-Return the 02 sensor and hope it starts reading something from a new one.
3-Get another M3 midsection, because the cats are bad? After the above has failed, of course.
4-Suck it up and put the 323 exhaust back on. (REALLY don't want to do this)
-OR-
1-Clear the code so the car is unready, take my invoice for 02 sensor with me to DEQ, and plea for a waiver.
2-Get the guys at DEQ to let me take the sniff test instead (yeah right, maybe if I didn't live in the city).
Damn I hate emissions control.
Anyone have any suggestions, advice, personal experiences with said project? Thanks in advance.
I put 96+ M3 exhaust (headers back) on my 99 323iS, fit great, plugged the right side, put my 323iS 02 sensors on the left header and cat (I read on here a while a back that a couple guys did this exact thing with no issues whatsoever). Problem... I didn't run the post-cat sensor wire well, and it melted; check engine light came on. I only drove it for two days before this happened. BTW, it runs and sounds excellent, no issues except this 02 sensor.
I replaced the 02 sensor with one of the M3 post-cat 02 sensors that came with the used exhaust, not sure if they are the same or not? I never was able to get the check engine light to stay off, or to read from the bank 2 sensor at all (I have proscan OBDII software with an Elmscan interface). Reads fine from bank 1 sensor, gets lots of data. I figure, must be a bad 02 sensor, or maybe they are different for the M3. So I get a new 323iS post-cat 02 sensor and put it in yesterday.
Well I hook up the lappy and the new 02 sensor behaves exactly as the old M3 one did... Won't read with my scantool, and outputs 1.015V constant according to the logging with Proscan (this is only data it can read, there should be much more, and this voltage should be fluctuating constantly, as is the pre-cat sensor V output). I can't pass DEQ like this, of course, because my check engine light keeps coming back on with a bank 2 oxygen sensor error.
Potential causes:
1-New 02 sensor also bad? doubtful.
2-Catalytic converter no good? Maybe... but I would think it would still be able to read from sensor 2 even if cat was bad, wouldn't it?
3-When the wiring melted on the first sensor installed (above), it maybe shorted out something in the computer and now it cant read the sensor properly anymore? I have no idea if this could be possible or not.
4-Hooking the M3 sensor up to it was a bad idea, and maybe damaged the computer somehow? I don't think this is likely at all, but who knows.
5-Or maybe it just won't work like this, because my sensors are reading exhaust from 3 chambers now instead of all 6, and the computer is expecting a totally different range of info? But those other guys got it to work fine supposedly... were they telling the whole story?
Potential fixes:
1-Change post-cat 02 sensor over to the right (as in left/right) pipe and hope it starts reading something with that cat.
2-Return the 02 sensor and hope it starts reading something from a new one.
3-Get another M3 midsection, because the cats are bad? After the above has failed, of course.
4-Suck it up and put the 323 exhaust back on. (REALLY don't want to do this)
-OR-
1-Clear the code so the car is unready, take my invoice for 02 sensor with me to DEQ, and plea for a waiver.
2-Get the guys at DEQ to let me take the sniff test instead (yeah right, maybe if I didn't live in the city).
Damn I hate emissions control.
Anyone have any suggestions, advice, personal experiences with said project? Thanks in advance.