I'll try and keep it short. I've been running Megasquirt for the last year in my AW11 without trouble and have been converting it to Coil on plug the last few weeks using SR20 coilpacks and a Smallport distributor.

It fired up while testing a few days ago but after tidying up my wiring I've somehow lost the charge and check engine light along with RPM reading while cranking.

However if I plug the factory ECU back in the charge and CEL turns on as usual again. Any ideas what might be up?

The Megasquirt still boots up and runs as expected.