O2 Sensor Question

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
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gainesville
I have two different O2 sensors in my car. One is a black sleeve over the wires and has three wires, the other is a white sleeve and has four wires. I was under the impression that EECIV wiring was set up for a 3 wire sensor. My buddy put in the 4 wire when we got ready for the first fire up after the rebuild. Since then I've had a miss and my passenger bank( the one with the odd sensor) reeks of fuel. Could the four wire sensor be the culprit?
 
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mustangO2Harness.gif
 
To the best of my knowledge you need the 3 wire. I replaced on of mine about a year ago. The 4 wire O2 are grounded through the harness, while the 3 wire O2 sensors ground through the body.

Wiring is as follows
gray wire is the ground
black is signal
white wires are heater

If you tried to use the 4 wire on a three wire car, you don't have a ground. The connector will actually plug in, but the mating connector on the car harness will not provide a ground and you can fry your EEC.

Are you getting a CEL?
 
yes, all my codes were for my smog pump and charcoal canister which have been removed. Had one for the TPS but that has been fixed. I plan on replacing both sensors, will pull codes and report back after that.
 
I have two different O2 sensors in my car. One is a black sleeve over the wires and has three wires, the other is a white sleeve and has four wires. I was under the impression that EECIV wiring was set up for a 3 wire sensor. My buddy put in the 4 wire when we got ready for the first fire up after the rebuild. Since then I've had a miss and my passenger bank( the one with the odd sensor) reeks of fuel. Could the four wire sensor be the culprit?
The 4 wire sensors are for the 4 cylinder cars. The extra wire is a ground, and I don't know if it is the sensor ground or the heater ground. You need 2 good O2 sensors with the 3 wire setup that the 5.0 Fox Mustangs use.