Oxygen sensor replacement

[Qgrappler]

Have two new sensors to put in from sparkplugs.com.

From prior posts, it appears its easier to get these loose from under the car. Does this mean just getting the socket on the sensor, and then turning the extensions and wrench from above?? Or hitting it completely from below? Experiences?

I do have the OTC tools crows foot sensor wrench.

Any tips on making the connection correctly for the wiring. Looks like the O2 plug must plug into a mating socket from the underneath of the connector. Not immediately apparent to me how to get to it.

And as long as I'm asking, which side is bank one v bank two on the engine.

Thanks

[3Q Jay]

haven't done this on either Q yet. I did do it on the alty.

zer...12902

don't forget the adapter sleeve(s) that goes between the exhaust mani an the sensor.

[DAEDALUS]

Driver's side is bank one. I've read of someone getting to both from above. I could only do 1. The other 1 was too close to the engine to go in from above. Can't help with the wiring, but when you have the new and old parts side by side it should be pretty clear.

[Qgrappler]

Allright, mid job update

Bank two sensor (passenger side) is done. That was the one that threw the code. Test drove it a little and it appears to run smoothly

Lessons:

It clearly would be much easier to do this job on a lift. I jacked the car on one side, used some safety stands in addition to the jack. There was VERY little room to get under the car on a creeper, and if I were not a little guy, I probably could not have got the wrench on the sensor.

But there was enough room to get my hand up over the pipe and get the socket on the sensor. Then, with the sensor wrench offset pointed toards the outboard, road side, I was able to drop a couple of extensions straight down the firewall and into the sensor wrench. (You can see all this with a flashlight from above on the PS, but not on the DS, as far as I can see.) Having sprayed some penetrating break-free stuff in there, and using a fairly long breaker bar type wrench at the top, I was able to break the sensor threads loose. Took a couple of tries and some waiting for the penetrating oil. (After that you have to crawl back under and unscrew the sensor all the way by hand, because of the offset design of the wrench (crows foot)).

I had a devil of a time getting the new one threaded in. Couldn't get it started....the wires on it didn't help, and I finally used a heavy piece of 12 gauge wire to thread down the firewall and pull the harness up to about where it would ultimately be.....that helped keep the wiring from trying to unthread the sensor as I was trying to turn it.

The plug on the end of the sensor plugs into the other plug at the top of the firewall. The sensor end plug is slid onto a small metal bracket held by a 10MM bolt to the engine. DO NOT REMOVE THAT BOLT. There are two little plastic grippers sticking through two holes in the bracket. Just press one while pulling and the old connector will come off the bracket, and you can slide the new one right on the bracket, and it clicks in. Then re-fasten the other connecter that goes into the upper wiring harness and you're in business.

I'm taking a rest before I tackle the drivers side. I would really recommed a lift. I could have gotten more torque on the sensor working from below with fewer extensions, but Im not sure I could have broken it free from the awkward position of laying on my back under there.

I ended up cutting the wires at the top connector and pulling them out from beneath on the old sensor. THe wires on these things are impressively strong. The old one on the PS has the wire going through a little harness point halfway up the firewall. More power to you if you are able to duplicate that with the replacement. I decided it was impossible to do and unnecessary.

Oh, the orginal one was a bosch in my 94 q45t. The tip looks a little different than the NGK from sparkplugs.com.

Took me about two hours overall to do this. A lift ought to cut that by at least 45 minutes.

In any case, my out of pocket so far is $50 instead of the $400 quote from the dealer.

Thanks for the tips.
Modified by Qgrappler at 3:47 AM 7/15/2005

[Aus94Q45]

The driver's side is harder to get to. I did mine with a combination of the crows foot, various extensions, and a flex joint. THe passengers side I broke from the top and then unthreaded the rest with finger tips from below. The drivers side was all from below. I did mine on jack, with stands and a big railroad tie block -- I do not want to be a cartoon pancake! Took about 30 to 45 mins per side. Be patient!!!

[maxnix]

Good job and good write-up. For me, it's always a lift. Too old, too fat, too out of shape, too scared.

[SardarQ]

Nice wite up .... Just wanted to share some thoughts on the O2 sensors...

97 Q45 --

I replaced the passenger side front so far - without lifting the car. If you have the O2 sensor socket and a long extension - its possible to slide into the sensor from the back. Place the socket on the senor first- then attach the extenion. Beofre you do any of that - spray with PB Blaster and leave for 10 minutes. It'll break loose. The New sensor is a pain to put in- but once in it's all down hill from there.

I plan on doing the driver side soon. I'll keep you guys posted - on the procedure.