Hey guys,

I'm getting a P0131 code, but I have a brand new O2 sensor, so I'm thinking I have a short somewhere. I've tested the harness plug and it has 12v from the white wire. When I test for continuity (on the O2 sensor itself) between the two same color wires (white) there is continuity, but when I test the two wires (blk/wht & blk/yell) on the harness plug that correlate to those two wires there is no continuity.

So my question is: should there, or shouldn't there be continuity between those two wires? Is there a short in my harness, or do I have a defective O2 sensor?

Thanks

I really don't know much about this stuff, so I hope I made it clear enough.

 

Measure the voltage on the blk/yel wire with the ignition switch in the ON (II) position (car not running).

 

I'm not sure I did it correctly. I'm pretty novice. I put the black lead from multimeter to ground, and the red lead to the blk/yell wire on harness. It's reading 10-11v fluctuating. Does that mean there is a power drain somewhere.

 

Aside from code P0131, is your engine having any performance issues?

These^ wires are not relevant to code P0131. The only relevant wire is the white (Wht) wire that runs from the O2 sensor to pin C16 of ECU connector C.

 

It runs like crap because it's in limp mode. If I clear the code it runs fine for about a mile or two. However I did just get a knock sensor code as well.

It is interesting that you brought up the white wire because I kinda wondered if it was the culprit. Here's the thing:

I bought this car from a guy who swapped this current motor into it. Mine is a 99 and the motor is from a 00. When I bought it the O2 sensor was not hooked up. The O2 sensor that was in the header was a different plug type. I purchased the correct O2 sensor for my vehicle, but the harness plug would not reach, so I had to add about 18in of wire to the harness. I've always kind of wondered if that is the reason why I'm having an issue. The white wire is actually an inner core of a thicker gray wire that has some metal shielding or something around it, which I discovered when I cut into it. I bought this car a couple months ago and this has been a giant headache ever since and I really just want to get it on the road. Any info you could give me would be greatly appreciated.

Thanks

 

Does the engine run significantly better if you unplug the primary O2 sensor? Was the engine running poorly even before the KS code appeared?

If you clear the KS code from the ECU, does it return quickly like P0131?

The Wht wire (O2 sensor signal wire) is and must be shielded. Post clear pics of your wire splicing work for the Wht wire specifically.

 

I will get pics to upload. The wht o2 sensor signal wire is coming out of a thicker grey wire, and it has a silver (not copper) wire (I'm guessing shielding) wrapped around it between the grey and white wires. Hopefully that makes sense.

 

 

Yes it was running poorly prior to knock sensor code. It seems like it's running rich.

I'm going to go take pictures right now.

 

Running rich would not make the engine run poorly. It's much more likely that the engine is running lean.

Test drive the car with the primary O2 sensor unplugged until the engine is fully warmed up. Did the unplugged O2 sensor prevent the engine from running like crap?

Does the KS code return after clearing it from the ECU and driving the car?

 

Do this electrical test:
Turn key OFF.
Unplug the blue ECU connector C.
Set your multimeter to read Ohms/resistance.
With the primary O2 sensor plugged in, place one multimeter probe on blue ECU connector pin C16 and the other probe on the metal frame under the dash.
What is the Ohm reading?

 

I will try those things. The problem is: I have deq where I live, and I cannot register the car until it passes, so I need a functioning o2 sensor.

Also, I may have found the culprit. I ripped all the wrapping off of the harness where I did added the wire, and my soldering job was dogshit. My soldering iron is old as dirt, so I'm going to buy a new one. Also the biggest issue I think I found is that some of the metal shielding around the white wire was touching the inner copper wire. My guess is that is no bueno. I would post pics but I'm honestly ashamed as **** after looking at it.

 

Yep. That's the problem.

 

I'm almost positive I just fixed it. I went and bought a good soldering iron, and I redid all the shitty bonds, and I stripped back the white wire's insulation a little further, so nothing was touching. Got her all wrapped back up, and plugged it in. She sputtered for the first couple hundred yards, and then started running normal. Haven't gone for a long drive yet. Thanks for the help.