While troubleshooting my son's 92 Camaro V6, I noticed the scan tool constantly indicates the engine is running in open loop. The O2 reading is very constant, not varying as much as I'm use to seeing. The car has this extreme power loss, which I'm being to believe is a restrictive CAT.. still not sure yet. Anyhow, what set of conditions for this application must be met to go into closed loop? BTW MAT temp is only being read by a sensor on the dirty side of the air cleaner. No codes are being set. Help!!

 

No codes make it tough since what ever the problem is isn't TOO bad, or not bad enough to exceed the diagnostic limits.

You need a min coolant temp., min time run, an O2 that generates a cross count, and no other malfunctions.

If the cats dead well then start there. Plugged exhaust will kill any engine. While the converter can melt closed, it can flake apart and plug up the muffler too.