Abstract: In a fuel injection system for an internal combustion engine with a fuel injection pump providing for an initial fuel injection and a main fuel injection wherein the fuel injection pump includes a main fuel supply passage section and a side passage and a main fuel control valve disposed in the main fuel supply passage section and an additional control valve arranged in the side passage, at low engine speeds, the main fuel control valve is closed during the initial and main fuel injection periods for generating a pressure sufficient to open a fuel injector nozzle and the additional fuel control valve is opened for reducing the fuel pressure and terminating initial fuel injection and, at high engine speeds, the main fuel control valve is closed during initial fuel injection and again for the main fuel injection.