What happens in the HEUI fuel pump chamber when the plunger PRIME recess registers with the pump chamber spill port?

Question

Quizplus · Accepted Answer

When the plunger PRIME recess registers with the pump chamber spill port in a HEUI (Hydraulic Electronic Unit Injector) fuel pump, it leads to a pressure collapse. This is because the alignment allows high-pressure oil to escape, reducing the pressure in the chamber.

What Happens in the HEUI Fuel Pump Chamber When the Plunger