Is there a sticky for this that I am not seeing? I do a search and some items come up but they are so old that there is not links anymore. I will be using a heated 3 wire O2 for my 1992's custom headers but need a little help if possible. I know it needs a switchable power source, ground and reading but I need to know where to hook each one up at. Sorry, I know this has been asked alot but thanks in advance. Maybe a sticky will help people on this too. thanks again.

The heated O2 sensors have either a 3 wire or 4 wire plug. You need to corresponding plug or cut the wires on the O2 sensor and put in your own plug. I'm going to assume the 3-wire sensor. Two wires will be the same color, these are the power and ground for the heater element. Hook one to switched ignition power, that is a pink with black stripe wire. The other goes to any ground. The third wire goes to the stock wire going to the computer for the O2 sensor.

kevin beat me to it, but i just wanted to say sweet ride!

Thanks guys, we are getting ready to start the beast up soon and needed this info. Man I hope it runs good.

I am putting a heated 3 wire o2 sensor now, it is a bosch, but I didn't right down the part number. It has two white wires with no stripes or differences, theres no writing either. I asked one of my automotive instructors, and he said that the black is the ground, and the two white wires are the power and signal wires.

So I tried it that way, I tried to measure the output voltage of the two white wires, but they were both fluctuating about the same numbers. So I simply let the car warm up for about 18 minutes, and drove for a couple of minutes, the service engine soon light, comes on with the code for the o2 failing. I know this, because there was a bad ground wire on the passenger cylinder head. So I fixed that and the 1 wire o2 was working ok, but I know it could be better.

So I figured the two white wires, the one that set the light was the power, and the other was the signal. So I simply connected the other wire and no more engine light coming on.

But I'm starting to wonder after what someone else stated in this post. If the black wire is going to a ground, the white wire may be acting as the sensor wire, so basically like a ground, but the signal instead. And if the heated wire, the other white one is to be connected to ground, its going to back feed through the ground black wire and change the values.

What do you think guys?

I read from someone else, that the key was to use the two white wires for the heated side ot the sensor, and the other as a ground, and the black one as the signal wire, and now the car goes into closed loop in 1-2 minutes.

So I think it works, lol.

You didnt search very long then

All universals (read the instructions) have two same color and one off color

Power/ground make no difference since you can swap either or

Off color is signal

Well, the sensor I bought wasn't universal, its off a k-1500 pickup truck, its a bosch one, two white wires and a black one. So I used the two white wires for the power and ground for the heater, and sent the black one to the original o2 sensor, it seems to work better. It starts faster and seems to be more responsive, I also lowered the fuel pressure to 37.5 psi, but I'm going to lower it again, and see if it runs better, because I felt a seat of the pants difference in performance.

Wow, that's pretty bad when even the instructor doesnt know. The black is the signal, and the two white wires are either power or ground. They're interchangeable.

Well its no big deal, I have it figured out, but it hasn't really helped the mileage much at all, it still kinda sucks, maybe around 16mpg with the bigger injectors, but it runs good.

just wondering if you can help i am a newbie who just bought his first 3rd gen and in the last month (which my wife hates) i have put in about 1200 or so into this car to get it to past safety and emmissions still not quite there yet. but i want to put a 3 wire o2 in it but where do you find the switched ignition wire is it in the engine compartment or in dash i have searched and searched and cant find where it is located. help please

You hook it up to the fuel pump relay, so it will be on for 2 secondsd when it primes the fuel pump, but once its running, it stays on. My mileage actually got up to about 20mpg, so not too bad.

Do not hook it up to the fuel pump. Factory 3rd gens already have rather small wiring for the load a pump requires. Pick another IGN source

Easy ones are the Emissions common (PNK/BLK) that goes to the smog pump, EGR and AC stuff or tap into the main IGN wire to the coil

thats rather funny, because I've done that and it works fine for me, and a lot of other guys on here have done the same thing. It has at least 16 gauge wiring, and that doesn 't take much amperage for the circuit so whatever if you don't think its a good idea. The relays are meant to take 30 amps already, so the wiring is also designed to take some amperage.