A bit of confusion here on how closed loop enable works.
App... 1997 SS 383-D1 MM6. OBD2 PCM.
I've been playing with new flash files trying to change the point of closed loop enable. I had a problem having the PCM to enter closed loop due to use of Evans NPG coolant and no T_stat.
How is closed loop enable triggered? I'm confused how this works.
Any Help?

Menu... The fuel tab/ menu "closed loop enable Temp C.
field entry... Below MAT
field entry... Above MAT
field entry... MAT threshold.

Thanx. Brad

 

I don't see how no thermostat would matter, the PCM should enter closed loop after the timer has expired and the engine is above the 'min coolant temp for closed loop' threshold (91 degrees F is my factory setting).

 

Theres a constant for closed loop coolant temp enable iirc, its the one used by many when they disable closed loop.

 

Most of the data logs I've reviewed indicate a 205-second timer, and a 140*F enable temp. And don't forget that the O2 sensors have to be hot enough to be active.