WARNING: DO NOT SMOKE, CARRY LIGHTED SUBSTANCES OR OPEN FLAME OF ANY TYPE WHEN WORKING ON OR NEAR ANY FUEL-RELATED COMPONENT. HIGHLY FLAMMABLE MIXTURES ARE ALWAYS PRESENT AND MAY BE IGNITED, RESULTING IN POSSIBLE PERSONAL INJURY.Section 03-04B: Fuel Charging and Controls, 5.0L and 5.8L Engines | 1996 Vehicles Equipped with 5.0L and 5.8L SFI V-8 Engines Workshop Manual |
WARNING: DO NOT SMOKE, CARRY LIGHTED SUBSTANCES OR OPEN FLAME OF ANY TYPE WHEN WORKING ON OR NEAR ANY FUEL-RELATED COMPONENT. HIGHLY FLAMMABLE MIXTURES ARE ALWAYS PRESENT AND MAY BE IGNITED, RESULTING IN POSSIBLE PERSONAL INJURY.
A powertrain control module (PCM) (12A650) accepts input from various engine sensors to compute the required fuel flow rate necessary to maintain a prescribed air/fuel ratio throughout the entire engine (6007) operational range. The powertrain control module then outputs a command to the fuel injectors (9F593) to meter the appropriate quantity of fuel.
The system will automatically sense and compensate for changes in altitude (i.e., from sea level to mountainous regions) and will also permit push-starting the vehicle should it become necessary (manual transmission only).
The fuel delivery subsystem consists of a high-pressure in-tank mounted fuel pump (9350) and a fuel filter/reservoir delivering fuel from the fuel tank (9002) through a 20-micron fuel filter (9155) to a fuel injection supply manifold (9F792).
The fuel injection supply manifold incorporates electrically actuated fuel injectors mounted directly above each of the engine's intake ports. The fuel injectors, when energized, spray a metered quantity of fuel into the intake air stream.
A constant fuel pressure drop is maintained across the fuel injectors by a fuel pressure regulator (9C968). The fuel pressure regulator is connected in series with the fuel injectors and is positioned downstream from them. Excess fuel, supplied by the fuel pump but not required by the engine, passes through the fuel pressure regulator and returns to the fuel tank through a fuel return tube.
The SFI system is controlled by the powertrain control module. If at any time, the powertrain control module malfunctions, or the battery voltage drops to an abnormal level, fuel injection will occur for all cylinders simultaneously once every two revolutions of the crankshaft.
The SFI system works in conjunction with the engine control system. This engine control system consists of the powertrain control module, various sensors, and switches. These sensors and switches send input signals to the powertrain control module. Based upon these input signals, the powertrain control module controls the timing and duration (pulse width) of each injection.