ECM

For discussion - I see no reason why cylinders can't be timed differently with waste spark ignition systems if one wanted to experiment. No two cylinders fire at the same time.  I used a GM DIS and it always knew which cylinder it was sending the combustion spark to.

I put about a thousand hours on megasquirt one, then megasquirt two for fuel, and then megasquirt with ignition (MSnS) on my subaru.  Not as  the primary efi system but rather as truly independent backup systems right down to the little alternator and battery.  Problems did crop up from time to time. The GM DIS cps that I used became unreliable after a couple of hundred hours but a different input circuit fixed that. An ignition driver started arcing through the silicone pad to the heatsink after about 500 hours or so.  It was a very low cost fun adventure but as with any one off system it can take a long time to establish weak points and total reliability.

Ken

Thanks for the insight Ken. I did more research and found the actual cost of the Rotax ECU, fuse box, and their fuel pump assembly is right at 12K !! Unreal. I also discovered Rotax houses the capacitors for the CDI in the missing “fuse box”. Already have a reliable alternative ?