O.J.

I am trying to wire in a heated O2 sensor on my 81 with Hooker sidepipes.

I am posting a photo of my O2 harness. The left side (two red wires are from the main harness. The right side (black and white) are coming from the old sensor.

My new O2 sensor is a Bosch heated 4 wire. It has a black (signal wire), 2 white wires (heater wires) and 1 gray wire (ground).

I have
-one of the white wires and the gray wire grounded to the engine block
-the second white wire I assume has to go to a switch power source to power the heater when car is on
-the black signal wire i am guessing connects to one of the original wires, which one? and what happens to the second?

Thanks for the help.......I hate wiring!!!

a1sensei

This is just a guess (the shop manual was not much help); If your wire color code is correct, you might disconnect the gray wire from ground and hook it to the other ECM wire. The original sensor had both wires going to the ECM. The sensor works by varying resistance as the O2 content changes and it may not be polarized, which would mean it does not matter which way you connect the two ECM wires. As I said, this is just a guess, you are into uncharted territory. Good luck and be sure to post your findings here!

God bless, Sensei

Richard454

I'm no expert on O2 sensors...

HOWEVER -I had to replace the O2's on my wife's BMW M Roadster. I learned a few things when the OBDII codes told me the heater element was bad after the Check Engine Light came on. The heating element was switched on and off by the computer-It was not a constant source like you are talking about running a switched ignition source to heat the element.

From my understanding the heated element will only help your car run cleaner/adjust fuel mixture when it's cold. My wife's car ran fine when warm and just stumbled a bit when it was cold-and noticed no change in fuel mileage while running the sensor w/ a burned out element.

I would just not bother w/ the white wires. You have no way to control the heating element.

Richard

noonie

They gave you the wrong sensor
It should be Bosche 12028, 2 wire
and it is unheated.
O2 sensors do not all create the same voltage and can damage your computor besides not getting out of open loop and basically operste as Richard454 described.
You must use the correct one.

Should be available at NAPA, Checkers, Autozone, Pepboys etc.

Z-man

He's probably got a controller to heat the sensor.

OJ - was there a diagram with the controller? Are you using an aftermarket computer?

O.J.

from reading countless hours on this forum, I believe I have the right sensor for the following reason.

-I am using the stock computer and dist
-I am eliminating the airpump, ERG and all of the smog stuff
-I am using aftermarket Hooker headers and sidepipes which force me to move the O2 sensor further downstream in the pipe.
-moving the sensor further from the engine allows engine heat to decrease causing an improper reading by the O2 sensor, thus the reason behind the use of the heated O2

There was no diagram with the sensor, simply an explanation of which wire does what. ie both white=heater, gray=ground, black=sensor.

Sensei might have it right, can someone else confirm? I just don't want to fry a $70 sensor.

Thank all of you guys for helping me figure this out, keep the info coming!!!

noonie

There are 3 types of heat control for sensors.
The very early type used 12v ign switched. Make sure your sensor is for pre obd2. The others are controlled by the computor in different manners.
Don't know the exact sensor you have but,
The black on the old sensor should be signal and the grey ground. Have never seen a sensor where grey was not the ground and they are polarized.


Also test the voltages to make sure they jive with the original output specs, like I said they are not all the same for output voltage.

O.J.

TTT...can anyone else chime in? I know someone has done this O2 swap, I read it on here somewhere.

Thanks
OJ