Not O2 Brute’, more mowing

Yesterday we had another dry day.  I took advantage of it and mowed down the area I skipped the night before.  There was still water on the ground in spots but it’s level was low enough that I could go over it without throwing H2O.  When the huge backyard area is given a complete hair cut it just makes me feel good, not sure why.

After finishing up the mowing I jumped right into yet another automotive maintenance project, this time replacing the O2 sensor in Cindy’s Miata.  The car has had a check engine light since she bought it.  I jumpered the diagnostic terminal on it and got back a 15 code which means the car computer is not getting a reading from the O2 sensor which is on the exhaust header, before the catalytic convertor.  The fix is supposed to be simply replace the sensor.

I have never replaced an oxygen sensor on a vehicle but I have heard horror stories about it.  These stories typically revolve around the old sensor being practically welded in place due to being subjected to extremely high exhaust temperatures day in and day out.  I read various tricks to assist in breaking loose the sensor without breaking it.  If you strip the head you now have a much larger headache, trying to get the remains of the sensor out of the exhaust header.

I figured I would stack the deck in my favor by having the proper tools in hand.  I bought a big 22mm wrench and special socket, specifically designed for O2 sensors.  It has a slot in it that allows you to slide past the connector wire and still get onto the fitting.

Another trick I read was removing the sensor while the engine is hot, the heat makes it easier to break the adhesions.  Of course in order to do this safely I put on my heavy duty Dewalt work gloves.  Trying to get the sensor out of a hot motor with bare hands would be a surefire way to get a lot of severe burns.

So I put my special socket on the old sensor and attached my 18 inch breaker bar to it.  I expected massive amounts of torque were going to be required to break the sensor free.  Imagine my surprise when with hardly any effort the old sensor spun free, I didn’t have to yank at all.  That clued me in that there was no way this was the original O2 sensor and also whomever put this one in did not torque it very hard at all.

So I backed out the old sensor and looked at it.  It didn’t appear to all that old but I had no way of knowing exactly how long it had been in there.  Before installing the new sensor I applied some of the included anti-seize stuff to the threads, being careful not to get any on the part of the detector that extends into the exhaust.  I turned the new sensor in, reconnected the wire and that was that.

After disconnecting the battery for a couple minutes to clear stored CEL codes I took the car out for a test drive.  Cindy said typically the light comes on after 3-4 minutes of driving.  The car felt peppier than I remembered as I cruised east on Immokalee Road.  I was 85% sure the problem was fixed.

Then, about 5 miles into the test drive the check engine light flashed back on, son of a bitch! I turned around and headed back to the house, dejected that my diagnostic procedures failed me.  I will be digging further into other possible causes for the error although a quick check didn’t reveal much short of a broken wire.  Automotive repairs offer varying amounts of satisfaction and frustration.  All I hope for is to keep the scales slightly tipped to the good side.

Alison is out of town again this weekend meaning I am back on dog duty.  I am picking them up tonight.  I am using the same strategy as the week before, my neighbor is going to help me out by letting out the girls during weekdays.  It’s such a big help but I feel badly for asking her for a hand again after only a week or so.