A fuel system includes a plurality of fuel injectors each having an injection control valve assembly, a direct operated nozzle check, a high pressure nozzle supply passage, and a check control chamber. A common drain conduit fluidly connects to each of the plurality of fuel injectors to receive drained actuating fluid. A plurality of pressure regulating valves each having a static geometry are positioned fluidly between the common drain conduit and the check control chamber in one of the plurality of fuel injectors. Operating a fuel system according to the present disclosure includes limiting cross-talk between injectors in the fuel system.

A fuel system includes a plurality of fuel injectors each having an injection control valve assembly, a direct operated nozzle check, a high pressure nozzle supply passage, and a check control chamber. A common drain conduit fluidly connects to each of the plurality of fuel injectors to receive drained actuating fluid. A plurality of pressure regulating valves each having a static geometry are positioned fluidly between the common drain conduit and the check control chamber in one of the plurality of fuel injectors. Operating a fuel system according to the present disclosure includes limiting cross-talk between injectors in the fuel system.

A control system for automatically adjusting air/fuel mixture in an internal combustion engine having a mechanical fuel injector system. The automatic air/fuel mixture control system has an electronic control unit which controls the quantity of fuel provided to the combustion chamber in response to sensor inputs in accordance with desired parameters.