That's a nice writeup bbjsw10,
I had an injector kill switch on a metro, problem was it wouldn't shut off cleanly. I switched to the camshaft pickup trick (disables ignition) and it is a much cleaner transition to off and restarting, and maybe I can reuse that fuel on relight
. You could kill both too with the right combination of relays, that would be more like what happens when the key is turned off.