4 wire o2 sensor
 

i know that i should just go buy a single wire but i have already welded it to my manifold. there are two signal wires, a signal wire ground and a signal wire + they both read on the a/f gauge but they act different.

does anyone know which one to use?
the gray(+) or black(ground) wire

nevermind, i went to autometer and found out which one to hook it to.

its the gray (signal +) for any who wanted to know.

I think some of the other wires are for the heater? o2 sensors nowadays are heated to get up to operating temp faster. Anyone know for sure.

there is signal to computer there is heater power and heater ground, and computer signal ground