Fuel Pump: Description and Operation

Fuel Pump:

Purpose:
The fuel pump supplies the injection pump with fuel from the fuel tank.

Operation:
All 6.2L diesel engines use a mechanical, diaphragm type pump actuated by a rocker arm through a link and pull rod.

The fuel pump rocker arm is moved back and forth by a rod which rides on an eccentric on the engine camshaft. The rocker arm pulls down on the pump diaphragm against spring pressure. This causes a vacuum in the pump chamber which draws fuel from the tank through the inlet valve. The camshaft rotates and releases pressure on the arm. This allows the spring to act on the diaphragm and force fuel out of the pump chamber through the outlet valve and into the fuel line diesel fuel injection pump.

When the immediate fuel needs of the diesel engine are satisfied, pressure builds in the fuel line and pump chamber. This pressure forces the diaphragm/piston to make shorter and shorter strokes, until more fuel is needed in the engine.

Location:
The fuel pump is located on the right side of the engine.