I have a apc air/fuel ratio gauge. I know it gets hooked up the sensor coming out of the manifold. Now the sensor have 4 wires coming from it one green, one white, and two blacks. The gauge hass 5 wires on it two are for the gauge to light up and the other three are one white, one grenn and one black. My question is wich black wire do I use that is coming out of the manifold?????

hang on let me go check my car

sorry dont remember and i covered everything with electrical epoxy to waterproof it. and i suggest doing the same because the first time i didnt and water got in and shorted out the gauge and my o2 sensor.