I keep seeing this mentioned>"if you run that thermostat" or "no thermostat" your engine wont go into "closed loop"?? I have a live data scanner that tells me my engine goes into closed loop before reaching 70 degrees.If any of you out there with a scanguage or ultraguage(or whateverguage for that matter) has the time please do temp vs closed loop test.I don't think your coolant temp has anything to do with your engine going closed or staying in open loop.At least not in my Disco......btw I use the torque app on my android phone with the ELM327 blutooth interface.

 

Closed loop occurs when the O2 sensors have heated up sufficiently to provide accurate feedback on fueling. Before this occurs you are in default fueling mainly based on MAFS/IAT input.
Once in closed loop there are different fuel maps that are based on engine coolant temperature, among other factors.

 

Running a "cooler" t-stat will not prevent your engine from going into closed loop.