According to the Haynes Manual I have here, the O2 sensor on an '86
325 is located just after the catalytic converter along the exhaust.
Just out of curiosity, why are you trying to locate it? My O2 sensor
on my '91 535 is placed right inside the catalytic converter, but the
electrical connection is in the engine compartment.
It might, but there's a whole better chance that it won't. When O2
sensors go bad they throw check-engine codes and the car idles very
poorly, but genrally not where the idle races up and down. Your symptom
sounds a lot more like a severe vacuum leak. Look around in the ngine
compartment for a hose that has blow off or cracked or a cracked rubber
intake manifold boot.
The E36 has a tendency to foul idle control valves. One that
is not working correctly will cause an idle fluctuation. First you
can try cleaning it by removing it and spraying well with throttle
body/carburetor cleaner. If it is especially dirty and stuck you
may have to replace it.
I had a really fickle E36 which required both an idle control valve
and an airflow meter to stabilize the idle. Just be sure you have
checked all the vacuum areas first.
I believe '86 was a cross-over year for the e30 6cyl engine controls. The
325es may have a separate ICV control box (green) in the glove box with the
ECU. In 1987 they ditched the separate ICV controller and integrated it into
the Motronic ECU. You may have it either way depending on manufacture date.
It's easy to check in the glove box, to be sure. If the ICV (under the hood)
has the 3-pin connector (square fuel injector type), the ICV is
Motronic-controlled. If there is a round 2-pin connector on the ICV, it has
a separate controller. Rule of thumb.
Bill in Omaha
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