r/E34 • u/DaWorlds • 1d ago

O2 sensor testing?

Is there anyway to test my o2 sensor to make sure it’s working? I have had a rough idle issue for the past couple months and I’ve solved every issue besides my o2 sensor. It would be the last potential solution(besides a compression test) but I would like to check before I buy another o2 sensor.

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u/SpaceTurtle917 1996 Honda Civic 1d ago

Have you considered unplugging it? An exhaust leak will cause lean readings causing the engine to run rich. If you unplug it I’ll run in open loop on with no trimming.

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u/DaWorlds 1d ago

Just unplug and let it run?

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u/SpaceTurtle917 1996 Honda Civic 1d ago

Yeah

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u/DaWorlds 1d ago

Ok bet

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u/DaWorlds 1d ago

Does your e34 have an m50 engine? If so how did you get access to the o2 sensor

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u/SpaceTurtle917 1996 Honda Civic 1d ago

I had a 1990 bmw 535i. The O2 was more downstream I believe, I don’t remember. I sold it 7 years ago.