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We're going to attempt to replace the O2

994 Views 4 Replies 3 Participants Last post by  Long Duck
sensor on my 92 E34 525i today without dropping the exhaust.
It should be interesting, especailly since it will just be up on Rhino ramps.
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How many miles?

How important is that thing to change?
123,XXX miles. I haven't a clue when the last time it was replaced. If it is as old as the mircofilter (stamped 05/95) I replaced earlier this week than it's probably that old if not older.


* We were able to get it done without dropping the exhaust. It took some time, but we did it. Gas mileage appears to be increasing. :thumb:
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Isn't that the primary purpose of the O2sensor... tell the ECU that it's giving too much gas. If it's shot, it runs lean and fuel economy sucks. Replacing it should boost your fuel economy.
The O2 sensor monitors and constantly adjusts the mixture.

Usually, when they go bad, the car goes into default mode, which is to run rich. (If default mode were to run lean, you'd burn a piston). That is why replacing a bad one usually increases MPG.
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