Timing and Metering Valves

[Nostalgic]

Here's how the 570 IFSM works:





And while 870/871 is shown, this shows how the actuators and injectors work in the same manner as the 570 (just that the IFSM on the 570 is unique in the way the pump and internal plumbing operates and it uses a different style of metering and timing actuators).