OXYGEN SENSOR REPLACEMENT
Changed the oxygen sensor today, very
simple. This is my first time changing it for the 65k miles I've had the car,
and I am uncertain that it had been changed at all before then. The replacement
I used is a Bosch #12051, price was $49, and I purchased it from my local import
auto parts store. The '85 MR2 uses a one-wire sensor.
Removal: The sensor is located at
the bottom of the exhaust header, near where it joins with the downpipe. Two
bolts hold the o2 sensor in place, 12mm I believe. Just undo these (see pics at
very bottom for the location), and pull the old sensor out. Don't forget to
remove the old washer that's in place. Let the sensor hang free, and run your
hand up the wire so you know where the plug is located. It's to the right of the
distributor, see the circled area below. Unplug the connector from above, and remove the sensor.
Here's a comparison of the old versus the new:
A close up of the sensors:
Close up of the plug:
And here's the washers (replacement sensor comes with the washer):
Installation: From the top of the
vehicle, plug in the new sensor, and then feed it down through being careful as
to how the wire is run around all the hoses down there. Insert new washer,
insert new sensor, tighten bolts. Voila! Now here are pics of the new sensor installed:
Before you start up the car, it's a good
thing to reset the ECU. Do this by pulling the AM2 fuse for about 40 seconds.
This fuse is located near the battery:
