Hi Mark, I can't speak for any of the other ecu manufacturers, only Gaspar's Fadec. I was involved in dvelopment testing in the earliest days and had the dubious honour of performing the first Fadec autostart in the World outside of Spain.

Things as always have moved on and although a manual start Fadec does not use the reverse voltage to assist bendix disengagement a good starter motor/bendix combination will naturally want to disengage once power is switched off. This is particularly so with the stronger magnet e-motors having higher braking force...this causes the motor armature to slow down much more rapidly than the bendix clutch which naturally 'snaps' back to the parked position due to the high inertial differencials involved.

Some manufacturers have gone a step furher incorporating a large thin rear flange/disc as part of the bendix mechanism, this takes advantage of the motor magnetic field to apply further parking/holding force away from the compressor nut.

Bet you did'nt realise so much development has gone into just starting an engine (and this is only a small part of it).

Rob.