I got a a/f ratio gauge yesterday and it has 3 wires red, black, and purple. I have the red and the black hooked up so it has power but the purple wire i'm not sure. I have been told the o2 sensor is that right

 

it would make sence, it needs to get info somewhere and power and a ground wont do it and i know they have to be hooked up to the o2 sensor so id say purple goes to 02 sensor.

 

Yup, O2 sensor

 

RED = IGNITION
BLACK = GROUND
PURPLE = O2 Sensor

Just make sure that you use a single wire O2 sensor.

If you get like a 3 wire or 4 wire...

Here are the AutoMeter Install manaul...


http://hp.autometer.com/instruction_...tions/837j.pdf


-Ryan