Hey i'm trying to hook up my air fuel gauge and i know that I need to hook it to the 02 sensor but I cant find which one! can someone please tell me which one and where it is located.


thanks

 

Any '96+ should have 3-4 O2 sensors. You will need any one of the sensors before the catalytic converter.

With the newer vehicles, you can purchase a scan gauge that will plug into the DLC (data link connector) and can display many different parameters from the PCM.

One such gauge is the AeroForce Interceptor Scan Gauge:

^^Click on the image for the website^^

I'll be getting one of these for my Bonneville when I start to modify it. This doesn't require any splicing into wires which is a sensitive issue when talking about O2 sensors.

 

Also thought that I would add that you should NOT hook into the O2 sensor wires between the sensor and the first connector. Reason being that all of the newer sensors use the wires to 'breathe'. Drawing in outside air to compare the oxygen contents with that of the exhaust gases.

So that limits you to playing with the wires in the main wiring harness. If working with the wires under the vehicle, you must make absolutely sure that you seal the wires back up or you could have corrosion problems down the road.

Now all of the sense wires go back up to the PCM located on the passenger side near the firewall. If I knew your exact year, I could give you the cavity location of the wires that you would need go get to.

*EDIT* - ah... nevermind...

 

hey that was really quick! I have a blazer xtreme 2002 4.3l

 

This should be the same for any '98+ Blazer/Jimmy/Bravada, but I will check when I get home tonight:
B1S1 Hi to C1-19 ---> Purple/White Wire
B1S1 Lo to C1-25 ---> Tan/White Wire
B2S1 Hi to C1-21 ---> Purple Wire
B2S1 Lo to C1-7 ---> Tan Wire

B1S3 Hi to C1-22 ---> Purple/White Wire
B1S3 Lo to C1-26 ---> Tan/White Wire

Now I included B1S3 because it has the same color wires as B1S1, but will not give you the proper readings for the purpose. It is the post cat sensor. C1 is the Blue connector into the PCM and the corresponding cavity number should be listed on the front of the plug (meaning you may have to remove it from the PCM to figure it out).

You'll want to use B1S1 or B2S1, either one will give you a good idea of what you want. You also could install a switched connection that could toggle between either sensor.

 

hey thanks for the help your awesome! The purple and white wire was the only one that worked but thanks!

 

Not a problem!

I thought that the high reference wire is the one you wanted. Other references of mine (after checking again) state that the Purple or Purple/White wire is the Signal and that the Tan or Tan/White is the low reference back to the PCM for checking the operation of the sensor.

Glad you got it to work though. Where did you end up pulling the signal from?

I only threw that scan gauge in for others that'll read this thread. They are VERY easy to install and allow you to look at sensor data along with reading/clearing trouble codes which makes them a very valuable gauge to have!

Glad I could help!