Fuel Delivery and Air Induction: Description and Operation
EARLY MODEL VEHICLESGeneral System Description:
Fuel System:
The fuel delivery system consists of the fuel tank, fuel pump, fuel filter, fuel pressure regulator, fuel rail, six fuel injectors and associated lines, and hoses. Fuel is pumped from the fuel tank into the fuel rail through the fuel injectors and the fuel pressure regulator, and returns to the tank via the fuel return line. The Engine Control Unit (ECU) controls the amount of fuel injected according to a programmed response to ECU inputs from sensors.
The 3.0L Multi-Point Fuel Injection System consists of six injectors which fire once per engine revolution simultaneously. Due to the fact that it requires two engine revolutions to complete one engine cycle the injectors fire twice per engine cycle. Thus the name, "simultaneous double fire injection".
The ECU controls the amount of fuel injected by controlling the length of injector "on time", this period of time is known as "injector pulse width".
LATE MODEL VEHICLES
General System Operation:
Fuel System:
The fuel delivery system is a Multi-Point Injection (MPI) type and consists of a fuel tank, fuel pump, fuel filter, fuel pressure regulator, fuel rail, six fuel injectors and associated lines, and hoses. Fuel is pumped from the fuel tank into the fuel rail through the fuel injectors and the fuel pressure regulator, excess fuel returns to the tank via the fuel return line. The Single Board Engine Controller II (SBEC II) controls the amount of fuel injected according to a programmed response to SBEC II inputs from sensors.
The injectors are fired in pairs, with each injector firing once per intake stroke.
The SBEC II controls the amount of fuel injected by controlling the length of injector "on time", this period of time is known as "injector pulse width".