Timing on the electronic pump is managed by the injection timing stepper motor. It uses a sliding piston that connects to the cam ring with a pin. As the piston slides in its housing bore, it causes the pin to rotate the cam ring to change injection timing.
There is an outlet passage from the charging annulus to the advance piston (figure 5-19). The pressurized fuel in this passage is used to move the advance piston. There are also drain passages in the piston housing.
