Oxygen Sensor

[mowfixer]

I do not have the Metro service manual so I have a question about O2 sensors.

I have been getting a random 13 code and since th O2 sensor has been in for 200,000 miles I guess its time to change it. The car is a 93 1.0L.

I was on a parts site and they talk about upstream and downstream sensors. I found the upstream one in the exhaust manifold but does this car have a downstream sensor near Cat converter? I looked underneath but can see enough to tell.

Thanks

[Crvett69]

93 will just have a 1 wire sensor screwed into the exhaust manifold

[mowfixer]

Thanks.

How the devil do you get it out? there is little clearance between manifold and radiator and its quite a large size. My wrenches would not fit.

[GM Line Rat]

Originally Posted by Crvett69

93 will just have a 1 wire sensor screwed into the exhaust manifold

I've been meaning to ask this question...The 94 2 Dr Metro (Automatic Trans) I used to drive had a 1 Wire O2 Sensor in it. When the tranny died in it and I picked up my latest 94 4Dr metro, 5 Speed manual trans (Engine dead with low compression).....I Swaped the entire long block out of the 2-Dr and into the 4Dr, But used the complete 4-Dr intake, exhaust mainifold, Wire harness etc... Then I noticed that it had a 4 Wire O2 Sensor in it...... What's the Difference between the 2 of them (1 Wire and 4 Wire)? BTW, I've had no problem removing the O2 Sensors in the car with the correct size open end/Box end wrench. Disconnect the O2 Wire(s) 1st, then break it loose and unscrew it by hand after a few turn with the wrench.

[Crvett69]

in mid 94 they went to the 4 wire sensor, it has 1 wire for ground, 2 for a preheater and 1 for the sensor. to remove it you can take the fan out and use a O2 socket you can buy at most parts stores or use a box end wrench. new one wire sensor should cost less than $20. the 4 wire ones cost around $60

[GM Line Rat]

Originally Posted by Crvett69

in mid 94 they went to the 4 wire sensor, it has 1 wire for ground, 2 for a preheater and 1 for the sensor. to remove it you can take the fan out and use a O2 socket you can buy at most parts stores or use a box end wrench. new one wire sensor should cost less than $20. the 4 wire ones cost around $60

I picked up one of the O2 Sensor sockets from autozone a couple years ago and it works great on those "Hard to reach" FWD cars with O2 Sensors Mounted in the rear exhaust manifold, such as our 91 Buick Century 3.3 V6....BTW, Thanks for the info Crvett69.....At $60.00 though, Looks like i'm gonna have to keep an eye out on E-Bay for a new 4 wire Geo AC-Delco O2 Sensor for a spare. AC-Delco O2 Sensors is the only type I'll use in all 5 GM Vehicles we own, Had too many premature and DOA failures with Bosch 02 Sensors i've replaced in various cars/trucks in the past..... .

[DOCTORBILL]

Ok - I just have to reply about Bosch O2 sensors....

I put a Bosch O2 sensor in my wife's Geo Tracker "about a year ago."

She had the CEL on for over six months and I couldn't figure out why - the
socket you short out did not work - no code!

Finally went to a shop and they hooked a "computer diagnostic machine" up to
the Tracker and it said O2 sensor!

I didn't check the O2 sensor as it was just replaced and worked!

So the mechanic lifts the hood and shows me the O2 sensor! It was wiggling
in the Manifold ! Wiggling! Completely broken away from the metal screw in
base but not enough to come out! Simply sitting in the metal base passing
exhaust gasses by the porcelean post!

I told them that I would replace it myself.

Came home and unscrewed it. The sensing part on the inside was gone!
Broken off. The porcelean post had come unglued from the metal base.

Never saw such a thing in my life. You couldn't tell that it had done that by
looking at it, so I never suspected it.

Bosch. I had not saved the receipt or box, so I had to eat the cost of a new
Borg-Warner O2 sensor - $87 at a local parts store (General Store in Spokane, WA).
The B-W O2 sensor is made in the USA.

The Bosch one only had the number 386 on the metal part....(?) Where are
Bosch O2 sensors made - China?

By the way folks - if you buy a new O2 sensor - cut the wires off the old one
just at the top of the sensor and save the wire-plug portion.

Then you can buy those O2 sensors that come w/o the plug that are cheaper.
Hook the wires up yourself! Simple enough....some soldering and heat-shrink
tubing insulation and you're good to go.

DoctorBill

[mowfixer]

One last question. This sensor looks rusted at the manifold connection. Are these a bear to break loose as a result?

I hate to break it off in the manifold.

[GM Line Rat]

Originally Posted by mowfixer

One last question. This sensor looks rusted at the manifold connection. Are these a bear to break loose as a result?

I hate to break it off in the manifold.

You wont break the O2 Sensor off in the manifold! Since it's been in there for 200K Miles:
Get a small hand held wire brush, such as a 2 way battery post cleaner etc... and a can of "PB-Blaster" (Loosen's and disolves Rust, you can get it at Autozone Etc..). With the wire brush, Clean around the area where the O2 Sensor Hex flange meets the Exhaust manifold, clean off any built up rust all the way around it, Start the car and let it warm up for about a Min, Turn the car off, Then spray some PB-Blaster on the area you just cleaned (Watch your hands on the Hot Exhaust manifold)....You should see it smoking a small amount. Wait about 20 secs, and spray some more on it till it's soaked. Now let it set for about 20-30 mins........Then break the O2 Sensor loose with the "Correct" size box end wrench or the O2 Sensor socket/Ratchet setup suggested above. When the O2 Sensor is out, wipe the O2 Sensor/ exhaust mainfold area down with an old cloth....Install new O2 Sensor and hook up Wire(s)......Done!

[DOCTORBILL]

Please - let me suggest that you also get one of those small 'envelopes' of
Anti-Sieze Compound (Costs $1 by the Register usually) and liberally put that on
the threads.

I did that on mine and they come out easily. It has powdered Aluminum and
powdered glass in it. That makes the threads stay "unlocked" if the unit gets hot.

Later on, the parts don't freeze together.

I put it on all bolts now so I can get things apart years later!

I even broke down and bought a tube of it!

Believe me, it is worth the effort to obtain it!

DoctorBill

[GM Line Rat]

Originally Posted by DOCTORBILL

Please - let me suggest that you also get one of those small 'envelopes' of
Anti-Sieze Compound (Costs $1 by the Register usually) and liberally put that on the threads.
DoctorBill

Good point Doc! Some (But not all) O2 Sensors come Pre coated with an Anti-Seize compound on the threads, and alot of times on the pre-coated Sensors....It's Not enough! You can usually tell the pre-coated O2 Sensors if they have a plastic protective sleeve around the sensor when you take them out of the box, to keep the compound from being wiped off in the packaging/shipping process.

[RossT]

The easiest way is to go to sears and buy a single stuby box end type wrench. Take your o2 sensor with you to sears to fiqure out what size stuby to buy.

You can get it from above, with the stuby wrench, without having to take the exhaust manifold off. Takes about 5 minutes.

[Crvett69]

they don't always come out nicely. i just replaced one on the rear of a 2000 camry, had to drop steering rack to get to it (V6 engine) and then use a 3' extenion and a cheater bar to break it loose. came out hard the entire way and were no threads left, had to go to store and get right size tap to rethread the hole, its in a steel factory header not cast iron manifold. the front on thats easy to get to so came out with no problems at all