3 wire o2 sensor

[smdk2500]

I have been reading about upgrading to a 3 wire o2 sensor. I do have a few questions. First off what are the benifits of doing this. Ive read mixed reviews on them.

2nd how do you wire them up. Is it just a power ground and signal? I have plugs and pins at work to make a plug for it so thats not a big deal. From what i can see in pictures there are 2 wires are the same color and one is blue or pink. Im assuming the 1 wire that is different is the signal.

3rd how does the heater portion of it know when to turn off? Is there something in there that turns it off when it hits a certain temp or is it just on all the time? If it is on all the time how does it not burn itself out.
Truck is a 95 2500 5.7

 

[CrustyJunker]

The two matching wires are the heater, the odd one is indeed a signal. I've read the best way is to hook it up is to the fuel pump relay. The temperature will maintain itself provided there's exhaust flow. You can hook the heater to any switched 12V source, but personally I would connect it to the fuel pump relay. Reason being - should you want to do any key-on / no-start troubleshooting (checking trouble codes, diagnosing circuits, etc.), the heater will only be on when the fuel pump is running. It can really shorten it's life or knock it out if exhaust moisture hits an already hot sensor.

 

[smdk2500]

Ok thank you. I haven't gotten around to ordering one yet but it is on the list of things to do.

 

[c1500deathtrap]

It helps you get out of open loop operation faster. Also keeps the sensor at proper temp if you've done exhaust work that flows nice. oh and you can move the sensor to the y pipe or crossover pipe so it actually reads both sides of the motor.

 

[smdk2500]

It helps you get out of open loop operation faster. Also keeps the sensor at proper temp if you've done exhaust work that flows nice. oh and you can move the sensor to the y pipe or crossover pipe so it actually reads both sides of the motor.

well oddly enough the o2 sensor is already in a position that reads both banks. My pipe rotted out right before the cat and i am just going to cut it out and put pipe in its place. Ive read on here that people say if cutting the cat out then it would be good to run a 3 wire but i could not find anything on how to wire it up. I read the wire diagrams but that didn't help much since everything was going to the pcm and not telling me what was power or ground.

 

[c1500deathtrap]

it should be the two black and one.... purple? one black is ground one is keyed 12v. purple goes to existing o2 signal wire. In the past i used the egr as my 12v source since i usually delete them.

 

[c1500deathtrap]

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Sorry about the mess on the counter, breakfast time. the two red wires you see are hooked to the two black wires (power/ground for the heater) and the blue (signal) is spliced into the old oem connector. certainly not the prettiest or most convenient way to do it, especially when its time to change it, but it works.

 

[c1500deathtrap]

Oh and the heater doesnt care which way you feed it power, so you can run power to either black wire.

 

[smdk2500]

ok thank you. I have plugs pins and new seals at work that should work to make it so all i have to do unplug it when or if i ever change it again. From the way things have been going with this truck it is probably the original. I guess if it is with 237k it has had a good run.