Hi guys, as basic as it may sound I am trying to hook up an air fuel guage & since I can't find a good circuit diagram anywhere I am not sure which wire to hook up on.
I have a 4 wire O2 sensor ( 1 black, 1 gray, 2 white)
I hooked up to the black, readings are kind of funny.
Which is the right one ?
Thanks.

The two white is the heater(+&-), grey should be ground and black the signal. But to make shure you can hook up a volt meter betwen a known good ground (engine block) and the black wire. Readings should be changing between 0.0 and 1.0V. But I`m only 95% sure about this.

yeah you're right rob, that's how my 4 wire is hooked up.

How much did you guys pay for yours? I searched autozone for the cheapest 4 wire they had and it was a $39 Bosch one. I don't know what car it was originally for though

As stated, $39 for the 4 wire, $19 for a single wire, genuine Bosch.

I doubt you gonna find anything better than $39. They`re universal cause they don`t have a model specific plug, you have to splice the wires. But it`s well worth it for that price.

or even the model of the car it came off of? my o2 has been reading wacko ever since it had a taste of c16.

I thought it should be right. So I guess it is my o2 sensor that is shot then. I also get my O2 sensors for the same Price. A buddy of mine told me that race gas kills O2 sensors, so whenever he takes his car to the track he takes a couple extra sensors along. Luckily he uses the single wire.
Thanks again Guys.

that's why mine's wacko, c-16 is race fuel, lead kills the cats and o2's.