I have been fiddling around with the CL stepper idle control feature and I am noticing some strange behaviour with it.
The engine runs perfectly fine with in OL mode.
I tried to tune the PID settings by following these guides:
viewtopic.php?f=18&t=3194&p=38092&hilit ... PID#p38092
Now when in OL mode you could see the stepper motor value by going onto Realtime Display under the tuning menu and then AllOutputChannels. In my case I set it to 26, and without any surprise, 26 shows up on the idleLoad channel. It also shows up on the IAC gauge if you choose to make it visible.
When I tried to do the same thing in CL mode I realized that the idleLoad value is being displayed as 2, which does not make any sense as the stable value is 31. If the idleLoad really was at 2, the engine should stall.
I did manage to get a stable CL control on some occasions and I would try to disrupt the engine by tuning on the AC or the headlamps. I have noticed that when under load the CL control would get the required rpm right, but when the load is removed, the rpm stays up. I would then try to increase the load further by switching on the AC, headlamps and thermo fan. The system would compensate by further opening the IAC and the AFR/02 would add more fuel and I would get the target rpm. When I remove all loads I end up with a very high rpm, which again does not go back to the target value.
With the loads removed, the IAC gauge and idleLoad channel would show 2 steps.
Is this some kind of bug where the system thinks that the IAC is closed and hence it makes no attempt to reduce the rpm? It is as though the system forgets about the position of the stepper motor, but I could be wrong.
In other instances the CL control does not work at all.
I am using the latest February 2020 firmware version.