open loop/closed loop operation
 

Hey guys,

So I'm trying to understand the different modes our fuel system has on our cars and was wondering if anyone know the specs as to when our cars are supposed to go into closed loop operation from a cold start. any help in this matter would be much appreciated as I am trying to figure out whether my thermostat or o2 sensors need to be replaced as I am getting a rich condition on my long term fuel trims of around -15%.

Anybody?

The FSM has a good description of open- and closed-loop operation.

Was trying to find that, but failed obviously lol

Many PDF readers will search all the PDFs in a folder. Put all the PDFs in a folder and tell your reader to search that folder for "open-loop", "closed-loop", etc.

thanks south....wouldn't happen to know what would make an engine overheat when all sensors are functioning correctly and radiator cap and catalytic converters have been changed out already would you? also am getting hot air from heater so I know thermostat is functioning.

Not sure. First thing I'd check is that the fans are running (and no obstructions to air flow across radiator). If they are, I'd remove the radiator cap (when engine is cool) and check for flow after engine warms up (stat opens).

O2 sensor and/or wiring may have been damaged when you changed cats. The sensors are semi-fragile and won't handle an impact wrench nearby.

I have no idea what else it could be. Another good excuse to pull out the FSM.