A fuel injection pump (100) provided in a diesel engine, including: an electromagnetic spill valve (20) configured to adjust a fuel injection amount by releasing a pressurized fuel with opening/closing of a spill valve body (23); and an ECU (Engine Control Unit, 50) configured to form a current waveform of drive current of the electromagnetic spill valve (20). The ECU (50), during the warm state, detects a valve-close timing of the electromagnetic spill valve (20), forms an optimum current waveform of drive current based on the detected valve-close timing, and applies drive current with thus formed optimum current waveform to the electromagnetic spill valve (20), whereas, during the cold state, the ECU (50) applies only drive current with a pre-set current waveform to the electromagnetic spill valve (20).

Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a high-pressure fuel pump operable to increase fuel pressure from a first pressure to a second pressure, a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors each of which is operable to inject fuel to individual cylinders of an engine, a pressure sensor operable to detect a pressure of fuel at the common fuel rail, and a controller operable to diagnose a condition of the high-pressure fuel pump based on output from the pressure sensor.