This type of electronic injection uses a camlobe to run the pump portion of the injector, and a solenoid inside the injector to control fuel timing, start and stop duration = quantity. There is a bridge that connects two valves to one rocker arm for breathing.
A very ambitious project for sure. The full scale injector parts are not very big at all, 1/5 are real small.
You are using a Pintle type injector for a pump? would not a needle type be a better pump? just thinking out loud.