You have to see whats not happening hot, no spark? no fuel? or too hot? the injector type system uses an engine temperature sensor and others to control fuel. it also has a way for checking trouble codes for these sensors. a bad sensor usually gives you an engine light, deferent year cars have different ways of getting codes, I'm not sure how to get codes from yours, but I think your problem is more likely a spark control module that the German's called an igniter. igniters control coil and you loose spark when they fail. at the beginning of their failure they work cold but stop allowing spark as they heat up