got a 91 tpi system with a 1 wire O2 and i put headers on the truck and bought a 3 wire bosch 13077 and i was wonderin which wire goes where and does what. because theres 2 whites and 1 black. i know ones a ground, ones a hot and then the actaully sensor wire. but help would be apprectiated. thanks

 

If you're looking at the 3 wire connector I'm pretty sure the sensor wire is the center wire. A continuity (ohm) test should tell you for sure.

 

nope i figured it out. the black one was the sensor, middle was ground and other power. but thanks

 

That's cool. Last time I replaced mine I wired it up with a GM pigtail so I don't have to remember which wire is which anymore.