I originally tried interrupting the cam and crank position sensors on my car, but they did not kill the engine either. Then I tried interrupting the ignition circuit, and that killed it, but it had unburnt fuel left over and on restart, it caused a SES light due to wacked out O2 sensor readings when the fuel hit the CAT. You could actually hear the rumble in the exhaust of the burning fuel. Finally I switched the common 12v supply to the injectors, and have been working (killing) great for over 2 years.
