I have just replaced the ignition switch, that was fun! Didn't help, same problem. Seems to me, based on the basic wiring diagram that I have, if the ignition power supply, ie. #15 wire is not suppling 12 volts, the motor should stop. This being a petrol engine, it does not have the vacuum connections to the ignition switch. And CPU's aside, the ignition should power off the whole system. What else could cause this problem?? Help.