Other functions

Some other functions of the fuel injection pump are:

Timing The timing is adjusted in response to engine RPM. At higher RPM s, the fuel pressure from the vane transfer pump is higher. Pressure changes effects a spring loaded plunger, and the resulting movement will move the cam rollers to either advance or retard the timing. There is also a cold start device which advances the idle timing manually.
Governor A mechanical governor limits the maximum speed of the engine to 4800 rpm in the bus/vanagon application and 5350 rpm in newer passenger cars. It can be seen just above the cam disk in the middle figure.
Stop A magnet valve or solenoid (shown in the figures) opens and shuts off the fuel channel between the feed pump and the metering pump.
Aneroid An air inlet pressure sensor is used to determine maximum amount of fuel delivered on injection pumps for turbo engines. On newer ('89 and later) naturally aspirated engines a similar arrangement is used for altitude compensation.