At the request of many members, here is a little how-to on installing the A/F Ratio Gauge.
Helpful Items for install:
*Protege Wireing Diagram book for you year
*10 mm deep socket with extentions
*3M Electrical splices AWG 14-18(no ghetto wire twisting or you will regret it later!)
*Assorted Bute Connectors AWG 14-18
*Loop Anchor connector AWG 14-18
1. There are 2 spots where you can splice into the signal wire for the 1st O2 sensor:
-At the 1st O2 connector Harness under the hood
-At the 1st O2 connector Harness at the ECU
Pick a place. If you splice in at the ECU, the wire you need is coming from ECU PIN # 60. This is the signal wire. It is a Pink Wire with a Blue stripe (P/L).
The ECU is located on the passengerside, under the carpet. You will need to remove the doorsill, and the passengerside kick pannel to pull back the carpet. The ECU aluminum cover plate will then be visible. This is where you will need the 10mm socket, as there are 4 nuts holding it in place. After removing the nuts, you will need to flip the metal cover over.
I advise use of leather gloves, or a cloth to handle the edges of the cover. THEY WILL CUT YOU!! After fliping over the cover, the ECU will be visible. The ECU harness connector has a bolt holding it to the ECU. Time for the 10mm socket again. Looking at the top of the ECU harness connector, you can see that the pin holes are numbered. Find wire number 60 and splice in there.
Here is a picture of the location of the ECU:
Here are some pictures of where I spliced into my 1st O2 sensor to give you an Idea of the underhood location:
And here is the entire album:
http://photos.yahoo.com/bc/linuxracr/lst?.dir=/A-Pillar+Shots&.view=t
To hook to the gauge itself, you will have to route through the firewall on the driver's side.
The A/F gauge itself usually has a positive (+) 12v wire, a ground (-), and the signal wire (that goes to pin #60). Find a suitable +12v source of ignition so that when you turn the ket to on, the gauge comes on. Anchor the ground (-) wire to chassis ground. In other words, find a screw going through the metal body of the car under the carpet under the driver's side kick panel, and ground it there with a loop anchor connector. The signal wire connection has already been discussed above. I hope all this helps!!