Hey,

I just got P1133. I had the same code last fall. I assumed the sensor was fouled by my old coolant leak which has long since been fixed and I have confirmed that I have not lost a drop of coolant in roughly a year.

Before taking the car out this spring, I replaced all plugs with TR55s, new front O2 sensor on driver's side (GM part) and now I am getting P1133 again after driving about 600 or 700 miles this spring, I would say.

I should also mention that it has been driving very well and just passed emission perfectly well (tail pipe sniffer) so I would assume that eliminates the possibility of a misfire causing the O2 to get fouled so quickly (as you will note in my sig, I have eliminated misfire detection because of the dbl roller timing chain and E-water pump, so I don't get trouble code confirmation of misfires).

I have no leaks on the driver's side header and have not had that header off recently so I could not have fouled the O2 with new, curing Ultracopper sealant or some such.

From what I have read, the most likely culprit appears to be a wiring problem (short). I have not closely examined the wiring back there so that is a possibility.

If it was wiring, would it not throw the code very shortly after being replaced, rather than many hundreds of miles later? It just seems to me that if it was wiring that I would not get this particular code.

What do you guys know about this?

Much thanks.

 

My OBDII book says look for the following:

Exhaust leak or other exhaust problem

Contaminated fuel

Backed out terminals, damaged connectors or wiring.

 

Based on feedback and other reading, I took apart the O2 sensor connector and cleaned all pins, etc. and erased the code.

After about a week and a half, the code had not returned and I was starting to feel pretty confident.

It returned again two days ago so I was hoping somebody could direct me to the multimeter testing procedure for the O2 sensor harness - (as well as the testing of the sensor itself with a multimeter). I know I have seen it but could not find it via search.

I would like to rule out any harness issues before buying a new O2 sensor (given that the one that is in there now only has about 800 miles on it).

Which gets me to what seems like the most likely cause of the problem

In an effort to resolve a stubborn leak between the header flange and the Y-pipe, I used a "generous" amount of Ultracopper sealant on the collector gasket - which seems to have beaten the exhaust leak.

The problem is that this junction is downstream (after) the O2 sensor in question but it is only about 2 inches past the sensor (these are SLP Shorty headers).

So the question is: I know Ultracopper can foul out O2 sensors but can anyone confirm that the Ultracopper is very likely the cause here - even though it is after the sensor (though just barely after it).

If the Ultracopper is my problem here, have I baked it enough to be confident that it will not ruin a new O2 sensor?

Also, are the plugs on that side likely fouled from running too rich on that side as a result of this code/sensor problem?

Much thanks for your patience and input.

 

Permatex UltraCopper is marked "sensor safe".

Did you add anti-sieze or any sealer to the O2 sensor when you installed it?

 

I used anti-seize on the threads of the O2 sensor but no silicone sealer of any kind on it.

I was careful not to get any anti-seize on the area of the sensor that is inside the exhaust pipe but I probably got some on the washer that seals between the sensor and the bung that is in the header itself.

I can't remember whether I used the anti-seize that came with the GM O2 sensor or the regular silver permatex anti-seize.

Thx.

 

I did use the copper-looking small plastic tube of anti-seize that came with the GM O2 sensor.

I am pretty sure I used too much though. I recall seeing vapour come up off the area around the front O2 sensor and I am pretty sure that this was excess anti-seize burning off.

It seems like this ruined the sensor. From what I have heard, the sensor compares the O2 it is reading in the exhaust to the ambient air and that it does this by sensing the O2 content in the air through the wires (is that correct?).

If that is so, would it be possible to clean off the wires near the sensor (perhaps with mineral spirits or some such) to restore the proper function? Long shot, I know.

I have no problem replacing the sensor, I just want to be sure of what my problem is - so I am not just throwing parts at the vehicle.

 

The sensor is a "thimble". The outside of the thimble is what sticks into the exhaust stream. The inside of the thimble has the ambient air in it. It gets there through the holes in the sensor for the wires. Any contamination on the outside of the sensor can ruin the thimble. Not likely you could clean it out. Putting any sort of solvent on the wires would just add to the contamination.