I bought a beat up 1990 740 with LH 2.4 bout a year ago, cold start injector has been connected to a switch inside the car for some reason, so starting the car while cold is a struggle with having to switch injector on and off all the time till the engine gets alittle hot, then it runs by itself, but in my understanding the ECU should be pumping extra fuel while cold without the need of the extra injector ? since it doesnt im guessing one of the sensors is dead and i got no idea what sensor to switch out. Would really appreciate some help

 

I'd look at the coolant temperature sensor located under the third runner of the intake manifold. If it's out of range it doesn't send the signal to the computer for extra fuel causing hard starting when the motor is cold.