Section 03-01C: Engine, 7.5L MFI | 1996 F-250, F-350, F-Super Duty Chassis Cab and Motorhome Workshop Manual |
The fuel/air mixture needed for burning in the cylinders is provided by multiport fuel injection (MFI).
Fuel is metered into each intake port in a sequential firing order. Fuel injector nozzle tips pulse to follow engine firing order in accordance with engine demand through fuel injector nozzle tips mounted on a tuned intake manifold.
The fuel delivery subsystem consists of a high-pressure in-tank mounted fuel pump, and a fuel filter/reservoir delivering fuel from the fuel tank through a chassis-mounted 20-micron fuel filter bracket to a fuel injection supply manifold.
The fuel injection supply manifold incorporates electrically actuated fuel injector nozzle tips directly above each of the engine's eight intake ports. The fuel injector nozzle tips, when energized, spray a metered quantity of fuel into the intake air stream.
A constant fuel pressure drop is maintained across the injector nozzles by a fuel pressure regulator. The fuel pressure regulator is connected in series with the fuel injector nozzle tips and is positioned downstream from them. Excess fuel supplied by the fuel pump, but not required by the engine, passes through the regulator and returns to the fuel tank through a fuel return line.