sensor output wire, which one?

[byebyebaby]

on the obd1 4 wire o2 sensor there is a black,green and 2 white wires coming off the plug, whuch one is the sensor out put wire?

 

[Dr Tweak]

It's probably the green. You can find out for sure by heating up the sensor (by installing it and starting the engine or by using a propane torch) and measuring for voltage between the green wire and the body of the sensor. It will produce less than one volt.

-Doc