MPC extruder tuning never stabilizes

[DLR3D]

I am currently testing using MPC heater control on my extruder, using the tutorial provided by your documentation calibrating to 235ºC (my usual print temp), the extruder is a e3d v6 with copper block and silicone sock, and during the calibration the following happens:

• Waits for ambient
• Heats up to set temp
• the console indicates it is "Performing ambient transfer tests" but it keeps cooling down the hotend very slowly never stabilizing, I allowed it to run for 1h30 and it still keeps on reducing the temperature slowly (it appears to be cooling down faster the longer it goes on)

As such I cannot finish calibration in order to use the MPC model.

Here you can see the graph of the last minutes:

What can be done to avoid this behavior?

Additional info, calibrating using the default setpoint of 200ºC finishes the first ambient calibration, although the calibration is still extremely slow first ambient transfer test, it took about 2h to slowly rise to the set temperature and stabilize. Something appear to be quite wrong causing some instability with the self calibration system.
The following tests with the cooling fan stalled 10ºC below the setpoint.
By what I can see by the log data and code it appears the main issue is the setpoint is set too high on the first pass causing a very very slow convergence, when it manages to. In my case the overshoot was about Maybe implementing more than 2 cycles using a more aggressive first loop so that the correct model information can converge faster.
I will try to implement a simple fix by aplying some correction to the assumed model, lets say 10% more, if the set temperature isn't reached after 60s and I will report back.

[Zeanon]

sry for the late reply
so the power stays low even though it should be heating up?
did you cap power in config?

[DLR3D]

No problem, I managed to fix the issue by retrying the calibration after setting the old PID values as default, after that the calibration cycle never failed again. Not sure if this helps

No, power was set as default 100% max