Got to get up early tomorrow, so this will have to be brief.
Open loop, means its running off a canned program, with minimal feedback from the sensors.
It does this while warming up, or if a sensor is out of its proper range.
Closed loop, means that it is using the data from the sensors to control the engine.
As to testing with the paper clip for that, not sure.
There is a series of conditions that cause it to go into closed loop. The engine has to be up to temp, the oxygen sensor has to be outputting the correct voltage, and all the other sensors have to be in range.
Its a set of conditions, not one single thing that causes it to go into closed loop. If all those conditions are not met, it will stay open loop.
The canned, or preprogrammed setup will change according to some sensors. For instance, there is a setup for a cold engine. When the temp gets up, it will switch to a warm engine setup.
If you go wide open throttle, it has a preprogrammed setting for that.
These settings are best guess settings from the factory to give you a generally good engine.
But, the closed loop system fine tunes things according to conditions. But, like I say, everything has to be right.
If it does not have good readings from all sensors, it will avoid closed loop, because it has no way to know what is really going on.
This is where the computer cable comes in. You can see all the sensors in real time to see which one is out of range.
If the darn thing would throw a code, you could probably find the problem without the cable.
I am suspicious of the oxygen sensor with the cold air temps you have. It may not be getting hot enough to work.
