I just purchased a 1981 320is with only 79K miles on it and replaced
the O2 sensor yesterday. It wouldn't surprise me if that was the
original O2 sensor. Unfortunetely, it didn't extinguish the light on
the dashboard. Is there a special button to press to get it to reset,
or is it supposed to be automatic? My owner's manual seems to imply
that the light with go out when the sensor is replaced. The other
issue I have is that the car idles a bit high, around 1200-1500rpm.
Just for the hell of it, I unplugged the new O2 sensor to see what the
engine would do. It dropped back down to around 900rpm. It went right
back to 1200-1500rpm as soon as I plugged it back in. I can't seem to
find any vacuum leaks anywhere and all the other sensors look good. Is
this just a matter of adjusting the idle set screw? I haven't checked
the ignition timing yet though. Any suggestions on resetting the O2
sensor light and the high idle? Thanks.