O2 sensor wiring

stangman16

Active Member
Nov 16, 2004
625
1
29
San Antonio, TX
My O2 sensor harness is toast... found out it was giving me incorrect readings and causing all sorts of pain.

I have the Probst book and my O2 connector does not look the same as the one pictured.

Pardon my horrible paint skills: :)

O2connector.png


Here's from the book:

Hego-1.gif



Please help me identify which wire is Hego Signal, PWR Ground, and Key Power. I would think that the black wires are the ground and Key Power is the white wire, but then it doesn't line up with that schematic. I can't go off my O2 harness either.

The O2 sensor is a bosch sensor
 
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jrichker

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The 5.0 Mustangs onlty use 3 wires for the O2 sensors. One 12 volt power to the heater, one signal out to the computer, one ground that is shared between the heater and computer signal.



Diagrams courtesy of Tmoss & Stang&2birds
88-91_5.0_EEC_Wiring_Diagram.gif


fuel-alt-links-ign-ac.gif



See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
(website host) for help on 86-95 5.0 Mustang wiring Mustang FAQ - Engine Information Everyone should bookmark this site.


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stangman16

Active Member
Nov 16, 2004
625
1
29
San Antonio, TX
The 5.0 Mustangs onlty use 3 wires for the O2 sensors. One 12 volt power to the heater, one signal out to the computer, one ground that is shared between the heater and computer signal.

Right. Got that, but I need to identify which wire is which on the sensor. The connector on the sensor is different from that which the book shows and from TMoss' diagram shows, I just don't want to take the chance of hooking it up completely wrong and damaging the sensor.

When I ordered the O2 harness, though used, it was stated for 89-93 mustang. Of coarse I now find out it was junk and the connectors are different. When I bought my O2's it was for a '92 mustang 5.0 LX, and it plugged right into that O2 harness. But I cannot find out what each wire is.

I plan on running PIN 43 straight to the sensor and pin 29 to the sensor from under dash where my computer is. (if not just for testing only) I can run a power ground from back of the engine bolt, and I assume the white wire on my O2 sensor is supposed to be hot while in "run" position.

Is the white wire indeed the power, and both black wires are ground? Does it matter which black wire goes to the computer and which one goes to the engine block?