I'm having trouble hooking up A/F gauge. The search turned up nothing for the EVO. Found this but it is for a Lancer: https://www.evolutionm.net/forums/sh...threadid=13468

I tried following these directions but luckily I decided to test continuity for Ground and the power first with my Voltmeter.

The power seems correct (the red wire), don't know about the white 02 signal wire yet, but when I tested the Ground on the thin black/brown wire it did not give a crystal clear ground signal. The wire above it (the thick black/brown) wire appeared to be fine.

So i'm not sure about hooking it up like that anymore. In previous cars, I always hooked it up to the source and I think I prefer it that way to do it on the EVO. Anyone know what wires do what on the first 02 sensor?

I guess the 02 sensor has 4 wires going to it:
Red, blue, black, white.

Can anyone confirm my guess at what the wires do:
Red-> power?
blue-> heater?
white->02 signal?
black-> ground?

Please confirm or post instructions for hooking up the A/F guage on an EVO.

 

Bump!

 

It might be best to tap into the harness under the dash as if you are installing an SAFC or similar device..

Positive power is pin 25 (red/yellow) pin 26 (Black) is ground. The O2 voltage is pin 76 (white).

 

you can't tap into the wire at the sensor, those wires are shielded and won't give you a signal. You have to tap into the ECU side of the sensor wire.

 

Thank you! Still confused though.

Which harness do you mean? The wiring harness going to the ECU behind the glovebox? If yes, then where is pin #1? top right of ECU?

I think the EVO ECU harness is very similar to this one (from the post I found above). The picture has 2 rows of 38 pins each... So pin 76 has to be on and end and Don't remember seeing a white wire on an the end of the harness... ???


(note, the ABOVE pic does not appear to be valid for EVO)

I have to see if the EVO harness has more than 76 pins....

 

ground would be just to the right (pin 26) of the positive power lead you show (25). The O2 looks to be the correct location, a white wire which is PIN 76, it is in the middle on the top row that you show with 5 pins on either side.. There are a total of 92 pins on the EVO harness. PIN # 1 is the top left most pin on your diagram and pin #92 is the bottom left most pin on your picture.

 

Thanks for more explanations but I must be a complete idiot as I still don't get how the pin counting works. There must be some numbers that are skipped somewhere. I hand counted all the pins in my harness and I only get a total of 76, not 92 like you state. What am I missing???

Here is what I did. I disconnected all the wiring connectors from the bottom of the ECU:


Then I flipped the diagram above so it matches up and I could easily map the pins in diagram to the harness on my car:


Then I tried to count the pins and make sense of the instructions. The way I counted, the O2 sensor pin is #60, not #76. Here is a picture of how I was counting:


I really must be missing something with the pin counting.... what am I mis-understanding?

 

I am reading this right off the Buschur Racing S-AFC instructions, not making this up... Looks like the connectors skip pins according to this diagram... So the first connector starting on the right of your picture is 1-26, the second is 31-46, third is 51-62 andhte fourth is 71-92. Hope that helps... Sorry for the confusion!

 

Ahhh... thank you. I figured there must of been some skipping going on
Well, tonight I'll hook it up and see what happens.

 

Ok, I finally got around to it and hooked up the A/F gauge. The above information has been verified to work properly on the EVO. Thank you cdavy for your assistance.

 

A mod should move this to the How To's forum.

 

So, which pin does the O2 sensor wire connect to? Better yet, what color is it?

 

The answer to your question is just above:
.... or, if you want to use my incorrectly numbered picture above, it would be pin #60 (in green).