eightTfourTA

iTrader: (3)

I noticed my neighbor's 94Z has a 3 wire o2. This caught my interest because I could get one locally from the parts store. I'm assuming that the wires are 12V, signal, and ground like the other 3 wire o2 sensors. Will it work right with my older ECM?

89Irocz23

yes it will just get the part # and so on for a vette I believe. You need the sensor and the connector.

eightTfourTA

iTrader: (3)

Same year vette?

Also, if it becomes a task to find the connector shouldn't I just be able to splice the signal wire like on a universal-type o2? Then just hook the 12V to ign power and ground to the block, right?

cfabe

Right, there are two wires of one color and those are power for the heater, polarity does not matter. the third wire is the o2 signal which is going to be the same signal as a non-heated sensor. Just splice it right in. Oh, and theres tons of applications for heated o2 sensors that will fit. You can ask for the corvette part, the 4th gen part, some s-10s had them, hell even my 91 escort has a heated O2.

Vader

eightTfourTA

iTrader: (3)

Thanks guys! And Vader, extra thanks for that wiring diagram.

eightTfourTA

iTrader: (3)

Ok now i'm a bit confused; the sensor I wound up with has four wires on it. Two white ones, a grey, and a black. If it makes any difference it's a Bosch sensor. Can I use this, and if so, how does this color code go? I have a guess, but I need to make sure.

Vader

Oh, SURE! Now you're changing from a 3-wire to a 4-wire. That's an entirely different situation (not really, but I just wanted to go off a little).

It's really just about the same:



In your case, the factory wire harness won't be there, so the colors aren't quite right, but you sensor should be like this:



I'm fairly certain that the two white wires are the heater element, the black is signal ground, and the grey is the O² signal. You can test the leads with an ohmmeter. The two whites should show the heater resistance, the black should show continuity (zero ohms) to the case ground, and the grey should vary with heat and oxygen.

Damon

The whites are definitely for the heater. Black could be the signal wire to the ECM, however. Is on one of the few 4-wire O2s I have laying around. I agree- check for continuity to ground (with O2 installed on vehicle) and that will be your ground wire, the only one remaining will be the signal wire to the ECM.

eightTfourTA

iTrader: (3)

Thanx guys, got it in and working. It's so nice to have a closed loop again! The black wire turned out being the signal wire. Grey's the case ground.