I'm toying with the idea of building Megasquirt for my 535i.

I have a spare Motronic 1.3 ECU and am contemplating fitting all the Megasquirt electronics inside the Motronics case and wiring the Megasquirt directly to the correct pins of the Motronic connector. This will enable me to use the original factory loom without having to modify it.

Fitting knock sensing and maybe a MAF are other possibilities but I'll start just with the Megasquirt first.

My main concern is will the OBC still work correctly if not using the factory ECU?