EDIT EagleMark: Question moved from another thread.

Synch vs Asynch fueling...

Synch fires with DRP. There may be a time delay, but it's DRP--Inj DRP--Inj. Asynch uses a strange method with an accumulator and an internal timer. Each time the code wants some type of quickie extra fuel it sends a request for asynch fuel to the accumulator. If the requested injector on time is less than the minimum asynch pulse value, the request is held in the accumulator. Once the accumulator value is equal to or greater than minimum asynch value, the injector is pulsed on the next cycle of the internal timer and the accumulator is reset. DRP has nothing to do with this one. If the accumulator value = (or is greater than) minimum asynch pulse, the injector is triggered.