Gauge wiring

[93/96 f-body]

I just bought a used dual pillar mount with Auto meter A/F and APC vacuum guages. I need to know how and the best way of wiring both and hooking up the vacuum. The A/F guage has three wires. Black, blue and Red. It's the narrow not wideband guage. I'm guessing i will need a A/f sensor in the exhaust? The vacuum gauge has two wires for the light pretty straight forward on that. I will check out both web sites for any info. I'm installing these on my 93 camaro. Once i adjust the valves and install my new Thunder racing plug wire kit. I'll update my profile. Thanks for any help. Keep the up with the good info. I miss the 96ss but the goodies are piling up on the 93!

[Injuneer]

Usually, the signal wire for the A/F gauges is purple, but it appears yours may be red = +12V, black = ground, blue = signal. Didn't it come with any instructions at all? If they are AutoMeter gauges, there are install instructions on the AutoMeter website.

The signal wire needs to go to one of the O2 sensor signal wires. You can splice into either signal wire at the PCM or on the vehicle wiring harness. It is generally recommended NOT to splice into the O2 sensor's stainless steel wire. The driver's side O2 sensor signal wire is purple/white on pin C20. The passenger side is the purple wire on pin C8. I hooked one up once by running both sensor wires to a single-pole/double-throw switch, allowing either sensor to be connected to the gauge. Be extremely careful with the splice. Its possible to screw up the O2 sensor voltage with a sloppy splice, or with voltage bleeding through from another wire. The O2 sensors generate voltage levels of less than 1 Volt.

After you are done, if its an LED gauge, you will have little more than a psychedelic light show in closed loop, with the lights swinging rapidly from rich to lean, back and forth too fast to mean anything. At WOT it will simply swing over to the "rich" reading, again providing you little useful info, since the stock narrow-band sensors are simply not accurate at anything other than 14.65-14.75 A/F ratio. Generally, it will tell you if you've lost a sensor or something catastrophic has happened to the fuel system..... other than that its useless.

I've never seen an electronic vacuum gauge, but I would suspect it reads the voltage from the MAP sensor wires (MAP wiring connector: black = ground; blue = signal) and somehow references it to barometric pressure (BAR - MAP = vacuum). Most vacuum gauges are not electronic. In that case, two wires would indicate they are simply the lighting positive and ground, and that you need to run a vacuum hose from the gauge to one of the (full) vacuum connections on the side of the intake manifold.

For the +12V wires, you want to used a switched power connection, and there is one in the fuse box on the end of the dash. Its a recessed 1/4" spade lug, labled "IGN". If there are wires for lights, tap into the output from the headlight switch so the gauge lights are only on when the headlights are on, or tap into the output of the dash light dimmer rheostat, or the fuse for the dash lights, if you want the gauge lights to dim with your dash lights. The ground can be run to any good chassis ground under the dash.

[93/96 f-body]

Thank you very much for your help. Sorry if i worded or mislead you on the Vacuum gauge. I knew that it had two wires and they were for the lighting. Thanks for the great info. You've always are a great help and i can't thank you enough. I'm not a pro at this stuff but asking questions and my mechanicals skills always have gotten the job done correctly. Hope to know half as much as you guys some day.

[ConElite]

You dont need to much of a thick wire. You need no thicker than a 14 or 16 guage.