good question.....we has been experience before.it will be depend to the installer how there do it. but the correct way is arm the alarm then the engine still running after just switch off by the timer.
actually i dunno wat does this call.. wanna call a immobilizer.. thnk is 2 much 4 tat..
wat i hav in mind is.. my fren has a car, which he did a little thngy on his ignition, when he wanna start a car, he needs 2...