Feeding pressure control is paramount for injection system performance stability, in order to provide the engine the same fuel quantity when equal electric command is provided to the injector driver. The present work is aimed at modeling a high pressure common rail diesel injection system and designing a rail pressure controller to be easily implemented on the electric board of a current controller for the injection system high pressure pump. In this project a simple but effective way of restoring rail pressure after an injection event is presented and compared with a more sophisticated approach involving a coupled controller with a compensator.