price_l

Just got my a/f gauge off ebay. It's used so of course no instructions. There is a red wire, black wire and a purple wire. Im guessing the red is power, black is ground and purple goes to the O2. Is this right? Sorry this is a repost. I posted it a while back and no one replied. Im sure someone has hooked one of these up before. Thanks for any info.

schwindty

Damn, I want one of those soo bad! hahah let me know how you like it once its hooked up! Is it a wideband o2 sensor that goes with it? If so you have to change the 02 sensor it's self and go with a 4 wire system. Sorry I couldnt help more dude!

Tims 88GT

the red is going to be your 12v source, and the black will be a ground, thoes are for the light at night so you can see it, the purple like you say should be for the sensor. but it sounds like you are missing something, who makes the gauge? call them and ask for directions. do you have a 5inch tac? if not i have one for sale.

302power

what kind of tac is it? How much you want for it?

silver91gt

yes, I have an autometer one and the wiring is the same
red-power
black-ground
purple goes to the signal wire on the o2 sensor.

the o2 sensor itself has 3 wires, one is power and a ground then the signal wire.
it took me about 2 minutes with a voltmeter and test light to find the right one.
I also hooked a switch up to mine to switch sides.

a wideband o2 sensor would be the best to get as it will give you realtime accurate results.
hooking to the stock o2's will tell you if it is rich or lean only at WOT.
the computer is constantly trying to adjust the air/fuel mixture so at idle and part throttle the gauge will continuisly bounce from rich to lean.