i have a a/f gauge already fitted in my saph but i have a lamda sensor and i am unsure which wire is the signal it has 4 wires 2 white 1 black 1 grey i think the two white are for heater but what about the other two is the black earth and grey signal any help much appreciated cheers

 

What a/f gauge do you have? If it is innovate you may to try use it lamda sensor for a/f gauge and as factory lambda simultaneously ...

 

i looks a like a lumenition 1 i have welded a boss in exhaust and have a lamdba sensor spare but dont know what the grey or black wires do i need to find which 1 of these goes to mthe gauge for the signal if that helps cheers