I have a problem. I lost the booklet that came with my air fuel ratio gauge. I have four wires coming out of the back of the gauge, Red, White, Black, and green. I figure that Red is positive, Balck is negative, but what is white and the green for? I know one has to hook to the purple wire under the hood coming from the O2 sencer, But which one? What does the the wire hook to? I have FAZE brand gauges. Any help would be great. thanx

Never mind i figured it out.