air fuel guage
Registered User
Joined: Mar 2001
Posts: 1,138
From: DFDub, TX
It goes to the wire coming from the oxygen sensor so it can show you the reading from it. I tapped mine into a wire coming out of the back of the computer. I can't remember exactly which one, but do a search on here for them and see if you can find it. There's a tech. page that tells you all about the wires.
Registered User
Joined: Aug 2002
Posts: 560
From: Chicagoland Area
The purple wire from the gauge can be tapped into the purple wire coming out of the back of the computer. You can find this wire in the bundle of wires that lead to the back of the computer. Just splice into that wire.
Administrator
Joined: Nov 1998
Posts: 71,094
From: Hell was full so they sent me to NJ
The left O2 sensor signal wire is purple/white, and connects to pin C20 (gray connector).
The right O2 sensor signal wire is purple, and connects to pin C8.
You can tap into either wire anywhere between the Os sensor connector and the PCM. Do not connect it to the wire that is part of the sensor.
Obviously, if you hook it to one sensor you only see 1/2 of the engine. To be able to select both sides, run the wire from each side to the outside connections on a single-pole/double-throw (SPDT) switch, and the center pin from the switch to the gauge. You can watch either side.
When you are all done, you will probably be disappointed in the results, unless you are into psychedelic light shows. In closed loop at idle and part load, the gauge is simply going to be swinging rapidly back and forth from lean to rich. It will only show a steady reading in open loop at startup, or at WOT. And since the stock O2 sensors aren't really very accurate at the relatively rich A/F ratios you need to make max power/torque, the readings on the gauge will tell you little more than that the sensors are working.
The right O2 sensor signal wire is purple, and connects to pin C8.
You can tap into either wire anywhere between the Os sensor connector and the PCM. Do not connect it to the wire that is part of the sensor.
Obviously, if you hook it to one sensor you only see 1/2 of the engine. To be able to select both sides, run the wire from each side to the outside connections on a single-pole/double-throw (SPDT) switch, and the center pin from the switch to the gauge. You can watch either side.
When you are all done, you will probably be disappointed in the results, unless you are into psychedelic light shows. In closed loop at idle and part load, the gauge is simply going to be swinging rapidly back and forth from lean to rich. It will only show a steady reading in open loop at startup, or at WOT. And since the stock O2 sensors aren't really very accurate at the relatively rich A/F ratios you need to make max power/torque, the readings on the gauge will tell you little more than that the sensors are working.
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