do you guys (with headers) run heated O2's because of the headers running cooler and ecm not going in to / staying in closed loop? i finished up my rebuild quite some time ago and although it's running, i have some other issues at the moment, but wondered if i should put a heated O2 on, and maybe a dumb ? here, but how can you tell if it's closed or open loop? i've got to find and fix this ground issue i have before i move on, but i need to be enlightened on the O2 issue, as well... thanks...

KAM

btw, this is on my '91 5.7L TPI with an LT4 hotcam and SLP headers, flowmaster catback.

 

I never noticed (with a scan tool) if my car went back into open loop at idle, but I did add a heated O2 just because the sensor is 6-8 inches further downstream than the factory. It honestly runs about the same. I read somewhere on the board once that jumping the A and B terminal on the ALDL when the car is running, the check engine light will flash in open loop, then stop stay solid in closed loop. Something like that..don't quote me but search around, see what you find.