Working on a friends 93Z that was swapped over to heated O2's. The car won't go into closed loop cause the ecm isn't seeing a voltage from one of the O2's.
I don't think it's in the wiring as I ran a test wire straight from the ecm to the O2 and it didn't change.
O2's are brand new AC Delco.
So, what causes the ecm to see 1092 volts all the time? Open circuit? Why?

 

I would start by check the resistance on the O2 wire. You know from the PCM harness to the O2. If that is ok I would swap the O2 with the other side and see if your condition changes. Also are you sure that the Eng is running correctly? I would think that if that voltage were accurate your car would be running like ****. If all this is good I would say your PCM is F'd up.

 

open circuit would be .450 mV so its either no resistance or infinite(?) resistance in the O2 sensor or like said above a bad PCM.

 

A new pcm is on order. The pcm in the car now is from Napa...so it's possible it could be bad.
I'll check the wiring again and swap the O2's from side to side again.
Thanks guys.