So I just replaced the O2 sens on my '95M yesterday and the whole thing is running better and the CEL went out, but it seems to be running extremely rich according to friends who were following me today when we were going to eat. Said they saw smoke no color indicated and forgot to ask, and that it smelled really rich. Do I need to reset the code in order for it to work proper again even though the CEL went out? Does the ECM take a few run cycles to relearn things and it'll simmer back down in a matter of days? car has been driven 3 times total since R&R, smoke was noticed during drive 2 OBD1 so only the one sensor, which car was running way less rich before the replacement. Puzzled.

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This post was auto-generated based upon a question asked on our tech article page here: BMW E36 3-Series Oxygen Sensor - O2 Sensor - Replacement (1992 - 1999) | Pelican Parts DIY Maintenance Article

The only way to know if it is running rich for sure, is to check fuel control using a scan tool or test tailpipe emissions. Otherwise it could just be cat odor.

- Nick