Quote Originally Posted by bb4pimp
how does the switch work?
An engine only needs air, fuel, and spark to run...you take any of of those variables away and there is no way for it to run.

A switch for the fuel pump prevents the fuel pump from coming on when the ignition is turned on and when the car is cranked. No fuel, no start.

You can do a battery cutoff but unless you have the memory wire on your head unit bypassing it you'll have to reset your radio stations every time you get back in the car (PITA). Also need the alarm bypassing it or it won't work The next best thing is a switch between the battery and starter that will keep the engine from turning over OR switches on the main ECU harness.

I've thought about building a butterfly valve to go in the air intake to prevent air from getting to the intake manifold, it would be just like a throttle body but with an electrical servo/motor on it to open/close it.

BUT again, none of this prevents a car from being snatched with a rollback.