I am installing a air/fuel gauge in my 97 tacoma .Does anyone have any Idea what wire is the signal wire for either the front or rear o2 sensor.The chilton manual does not offer much help.

 

why dont you find the actual O2 sensor and look at the wire and remember the color, then look at the ECU and tap into the wire there.

 

because our o2 sensors have 3 white wires and one black....I have the exact same question...

 

This may help:

http://c-67-170-224-64.client.comcas...ireColors.html

Or you could add a dedicated sensor for the A/F meter.

 

I had mine hooked to a purple one if I rember right. The 3rd gen had 2 blacks, one red and one black with purple stripe. I did this back in 2000 so Im not to sure. You have to take the volamerer and test for the 1 volt signal on one of the wire. 2 were grounds, one was constant power, the other varying signal. Sorry the english is so bad, IM super tired.

 

theres a guy familiar with electrical testing, get a volt-meter and find the wire that carries the signal and you know black is always ground so you've already accounted for what one of them does

 

Dont hold me responisble for the colors, IM legaly color deficant. I check the digram posted by Roger, it seems like his digram was right. It was 2 blacks, one white, and a blue. If I rember right I taped the blue? I gotta go check, but any use the volmeter and look for the singal wire, and not the constant. Im sure you can contact Brian or Gadget over at URD, and they should know

 

Ok now I have an idea of what wire on the PCM to tap but which signal wire should I get the feed off of the front or rear o2 sensor?

 

Front sensor would give you (and the ECU) information about the raw air/fuel mixture, the rear sensor tells you (and the ECU) how the cat is working. So I guess it depends on what you are interested in monitoring.

 

Rear if I rember doesnt send intermitent signals, it only shows on or off. Not a funtion read out like the front one. Tap the front o2 sensor