Cold Start Injector dumping fuel: rough running

[Ron in SC]

I figured out that my hot start problems and also rough idle when hot is caused by my cold start injector dumping fuel.

So the next question is the cold start injector defective or is there something else, i.e., a sensor that is telling it to do that that is the source of the problem?

With the electical connector on the cold start valve disconnected the car runs fine when warmed up. If I connect it the car immediately loads up and puffs black smoke.

[atikovi]

Maybe a temperature sensor is bad and sending a signal to the computer that it's always cold outside and the computer responds by activating the injector constantly.

[Ron in SC]

There are three temperature sensors or switches on the head and/or manifold that I know of. Starting from the front of the car and working backward they are: Temperature switch, Coolant temperature gauge sensor, and Coolant temperature sensor.

I don't know which if any of these are relevent to my issue and if so how to test them. My guess is the Coolant temperature sensor which has as I recall a four pole connector on it. I suppose I could take swap the one in my 300 TE and put it in the 300 E but I'd rather just test them if I knew how.

I suspect the sensors are way less money than the cold start injector.