AFM very technical question
 

Hi i'm new and i need help :)
I'm an e30 s14 enthusiast.
I own an s14b20 engine car: this is the 320is, the italian version of the M3 e30 that is s14b23.

I'm doing little experiments to better understand how this Motronic DME M1.3 system works and i need to ask you something:

When i force the AFM flap to open at idle speed by operating on the AFM cursor, the car dies due to an excessive rich mixture.
I was under the impression that at idle speed, when the TPS (throttle position switch) is closed (i can clearly hear the click and it is brand new) the ECU was bypassing the AFM (ignoring the LOAD signal) so no variations of mixture could have been achieved.

1) Why does this "idle enrich" happen?

2) Is this the same thing at Partial Throttle and WOT?

Thank you