Air/Fuel Meter Install
I purchased a dual gauge pod (Autometer Part #20674,Dual #20675,Single - about $20) from Summit Racing Equipment. I needed the dual pod as I also wanted my boost gauge to be easy to see. I initially used an Intellitronix A/F meter ($30 part #ITC-TH7009 from Summit). It was a decent gauge with a 10 bar graph display. I was quite happy with it, but decided to try Autometers new A/F meter because I liked the looks a little better and it offered double the resolution with a 20 point display. The Autometer gauge is pictured below and is an Autometer Sport-Comp (#3375) Air/Fuel Monitor ($50).
The Intellitronix gauge lights up its ten bars as it goes and leaves them lit. So at full rich you see 10 lights, at the halfway point you see 5 lights, etc. The Autometer gauge is sort of a floating point type. It only lights a small range around the current A/F level, so you see a sort of floating dot going around the edge of the gauge. I like the higher resolution of the Autometer gauge, but I think the display is slightly annoying with the dot flipping around all over under light throttle. I don't plan on putting the Intellitronix gauge back in, so I guess the Autometer unit doesn't bother me too much.
I won't go into the details of mounting the gauges in the pillar pods. You drill a few holes here and there and then run your wiring down the pillar cover into the area under the dash... then across the dash to the passenger's side kick panel. Be sure you don't pinch your wiring when finishing up at the a-pillar. Also be sure to secure the wiring you run under the dash so that it can't: 1) get pinched by something or 2) fall down and get tangled in someone's shoes. Make it look neat, damnit!
Now for connecting the wiring...
The ECU is located behind the passenger's side kick panel. Remove the door sill protector (it just pops up). Then remove the two plastic pop-out fasteners that hold the kick panel on. You can then pull the kick panel out, exposing the ECU.
Be carefull with the ECU. Don't pull on the wiring too hard. Be nice. If you mess up your car will misbehave in unpredictable, nasty ways.
For 12v+ find the 22pin plug that goes into the ECU. It is the lower most connector as the ECU sits in the car. To remove the plugs, depress the release catch on the plug and pull it straight out. The wire is on the upper corner of the connector and should be black with a white stripe. Mine actually looks like it has a silver stripe. It should be directly across from a blue wire with a red stripe. The connector number is 1B and is listed as the main relay.
For ground I used the same bolt that the ECU is grounded to. It is on the frame that the ECU is secured to. I know you wonder why I used a red wire for ground. It is actually a red wire with a black stripe, you just can't see the stripe.
The O2 sensor wire is in the plug that has 16 pins. I believe it is the third connector up from the bottom, but count the pins to be sure. The wire you are looking for is designated 3C in the factory manual. It is the black wire in the second column from the top (if you imagine the pins as being 2 rows x 8 columns = 16 pins). It should be across from a white wire with a blue stripe.
A few notes:
My car is a '93, as is my shop manual. Different cars may have different wire coloring, even for the same year... they shouldn't but I've seen it happen before.
If you use those little blue spade type connectors (as seen in the second picture above) for splicing two wires together in parallel, be sure you don't cut your 12v+ or O2 wire with them. On my car I removed those (I don't trust 'em but was in a hurry at the time). I went back later and carefully cut away a small amount of the insulation on the ECU wire and soldered the wires together. I then taped them well to prevent bad things from happening.
I think the best place to get the O2 signal is from the ECU harness. If anyone knows of a better place to get the 12v+ and ground, let me know... BTW, I am also running my ValentineOne (radar detector) off the same 12v+ source & ground with no problems at all.
Your mileage may vary... but that is what worked for me.
Use this information at your own risk... don't call me if your car explodes, dog catches on fire, monkeys invade your house, etc.