code 21

[Late]

after i put my engine last week i started getting code 21, i looked it up and it says o2 sensor deterioration. so figuring because my o2 sensor was old i bought a new one (denso 234-3051) and it has the correct plug but the code is still there after i tried clearing codes by pulling efi fuse and then disconnecting battery when that didnt work. when i was changing the sensor the receiving end of the plug on the harness broke so i just have the pins but i do not think that would cause the code would it?

also, my air fuel ratio gauge works

 

[IBoughtASupra]

The black wires are for power and they are non polarized. The blue is signal. Trace and make sure you have continuity.

 

[Late]

i just checked with a test light and both black wires have power, i do not have a volt meter at least i dont think i do

 

[IBoughtASupra]

Test light is easy. Put the battery clip on the ground, touch wire, if it lights, you have a positive.

Put battery clip on positive, touch wire, if it lights, you have a ground.

 

[Late]

yes i know how to use a test light lol, i thought you had asked me to test those wires, they are getting power to the pins and the blue wire has my air fuel ratio gauge attached and that works. im unsure why the code doesnt go away if everything appears to be working

 

[jetjock]

Crack me up. The answer is right there in front of you.

 

[Late]

are you saying the light is on because the plastic connector broke? that just doesnt make sense to me

 

[IBoughtASupra]

Both black wires are not supposed to have power. One a ground and the other is a positive.

 

[Late]

what would cause them both to have power then? im confused how that would happen, i didnt realize one was supposed to be ground

 

[IBoughtASupra]

Check your wires, maybe a broken on somewhere. How are you testing the wires? What terminal is the test light's clip on?

One should be negative, the other is positive. Check your wires. Are you getting those readings with the ignition on or off?

You should only get power there when your ignition is on...if you do with the key off, you have to look over your wires...

 

[Late]

i connect the test light to a hole in the engine bay for ground, while the o2 sensor is plugged in i touch both of the two black wires individually i get power on both, when i unplug the sensor only one of the wires has power, all while the ignition is on.

 

[jetjock]

...Both black wires are not supposed to have power...

Bingo. One chicken dinner to go

 

[IBoughtASupra]

^I respect for this guy. He helped me to figure out why my 7M was not idling due to the turbulence against the AFM.

"Teach a man to fish so he can feed himself," was the line, right Jetjock?

 

[Late]

can i just cut the wire and then ground it elsewhere with more wire? would that fix the issue?

 

[IBoughtASupra]

can i just cut the wire and then ground it elsewhere with more wire? would that fix the issue?

You didn't answer if the key was on or off.

 

[Late]

i said all while the ignition is on at the end of the post on top

 

[jetjock]

You also said you knew how to use a test light.

.."Teach a man to fish so he can feed himself," was the line, right Jetjock?..

Indeed. Not easy though is it? Some folks would rather starve...

 

[Late]

yes i know how to use a test light, i dont know what youre trying to say. im just trying to get help figuring out what is wrong with this because i dont understand why its happening.

 

[IBoughtASupra]

Turn off the ignition and see what you get.

Yes, you can just ground it to the body but I would fix it the correct way.....

Jetjock, I have seen many people on this forum who would rather starve.

Lucky I listened to you....I learned a lot about wiring. We have a shop and I was able to figure out a S10 that had a bad computer, checking OHMs and continuity before diagnosing that. Thanks man.

 

[Late]

with the ignition off i get no power on either one, im assuming thats how it is supposed to be. could the ground have just got pulled out of where it connects to the block (if thats where it does)?