Fuel Charging and Controls
Fuel System Components, Part 1:
Fuel System Components, Part 2:
The fuel system used on the 7.3L Direct Injection (DI) turbo diesel engine is controlled by the Powertrain Control Module (PCM).
The fuel system components consist of:
^ electric inline fuel pump.
^ high-pressure oil pump.
^ fuel filter.
^ oil pressure regulator.
^ oil pressure sensor.
^ fuel pressure regulator.
^ high-pressure oil pump reservoir.
^ water in fuel switch/fuel heater thermostat.
Fuel is drawn from the fuel tank by the electric fuel pump. The fuel is then supplied under low pressure, 352 ± 28 kPa (51 ± 4 psi), to the fuel filter/water separator assembly.
Fuel to be supplied to the combustion chambers passes through the fuel filter/water separator assembly into the cylinder head galleries, then through the hydraulically actuated/electronically controlled fuel injectors.
Excess fuel not used by the engine bypasses the fuel filter/water separator assembly, flows through the fuel pressure regulator assembly, and returns to the fuel tank.
Fuel Pump
The fuel pump is an in-line electric pump mounted on the left hand frame rail. The fuel pump draws fuel from the fuel tank and supplies it to the engine at 352 ± 28 kPa (51 ± 4 psi).
Fuel Injection Timing
The period of time the fuel injector nozzle tips are energized is controlled by the powertrain control module.
Fuel Injectors, Part 1:
Fuel Injectors, Part 2:
Single Upper O-Ring Orientation:
Fuel Injectors
CAUTION:
^ Color of Service Parts identification clip may differ from color of Production identification clip. Verify identification using part number and parts catalog.
^ Do not interchange fuel injectors. Improper injector installation can cause severe engine damage.
An electronically controlled/hydraulically actuated fuel injector is used. The rate shape fuel injector incorporates a spill control port that helps balance the fuel delivery, reducing the emissions and engine noise.
When the fuel injector is energized, a poppet valve is opened by an electronic solenoid mounted on the fuel injector. High-pressure oil from the high-pressure oil pump flows into the fuel injector and acts on the amplifier piston, forcing the piston plunger downward. As the plunger moves down, the increased fuel pressure closes the fuel inlet check ball. Rising fuel pressure overcomes spring pressure and opens the nozzle check valve. Fuel is then injected into the combustion chamber through the orifices in the nozzle tip at pressures as high as 124,110 kPa (18,000 psi). When the fuel injector is de-energized, high-pressure oil on top of the amplifier piston is vented by the poppet valve through the top portion of the fuel injector back to the oil pan.
Fuel Pressure Regulator
Fuel pressure in the cylinder head fuel galleries is maintained at 352 ± 28 kPa (51 ± 4 psi) by a fuel pressure regulator. The fuel pressure regulator consists of a spring-loaded poppet valve, which opens to allow excess fuel to exit fuel filter/water separator prior to being cycled through the fuel filter. Fuel exiting the fuel filter/water separator is returned to the fuel tank.
Oil Pressure Regulator
Fuel injection pressure is controlled by the Injection Control Pressure (ICP) system. The ICP system consists of the following:
^ injection control pressure (ICP) sensor (located in the cylinder head oil gallery)
^ Injection Pressure Regulator (IPR) located in the high-pressure oil pump
^ powertrain control module
Fuel Charging Wiring
The fuel charging wiring connects the engine wire harness to each fuel injector and engine controls such as the injection control pressure (ICP) sensor, injection pressure regulator (IPR) and Injector Driver Module (IDM). The fuel charging wiring receives fuel injector signals from the powertrain control module and the injector driver module then transfers the signals to the fuel injectors.