Fuel System Components - Gasoline; Fuel Injector; Fuel Rail; Fuel Filter - EDI TSG-416 Service Manual

Fuel System Components - Gasoline

The fuel metering system is made up of the
following parts:

The fuel injectors (gasoline)

The fuel rail (gasoline)

The fuel filter (gasoline)

The GCP

The Crankshaft Position (CKP) Sensor

The Camshaft Position (CMP) Sensor

The fuel pump (gasoline)

The fuel pump relay (gasoline)

The Direct Electronic Pressure
Regulator (Gaseous Fuels)

The Fuel Lock Off Solenoid (Gaseous
Fuels)

The Mixer (Gaseous Fuels)

The Vapor Regulator (LPG/CNG)

Heated Oxygen (HO2S) Sensor

Temp/Manifold Absolute Pressure
(TMAP) Sensor
The basic function of the air/fuel metering
system is to control the air/fuel delivery to the
engine. Fuel is delivered to the engine by
individual fuel injectors mounted in the intake
manifold near each intake valve.
The fuel metering system starts with the fuel in
the fuel tank. The fuel is drawn up to the fuel
pump through a pre-filter. The electric fuel pump
then delivers the fuel to the fuel rail through an
in-line fuel filter. The pump is designed to
provide fuel at a pressure above the pressure
needed by the injectors. A fuel pressure
regulator in the fuel filter assembly keeps fuel
available to the fuel injectors at a constant
pressure of 45psig. A return line delivers unused
fuel back to the tank.
The main control sensor is the heated oxygen
sensor (HO2S) located in the exhaust system.
The HO2S tells the GCP how much oxygen is in
the exhaust gas. The GCP changes the air/fuel
ratio to the engine by controlling the amount of
time that the fuel injector is "ON". The best
mixture to minimize exhaust emissions is 14.7
parts of air to 1 part of gasoline by weight, which
provides the most efficient combustion. Because
of the constant measuring and adjusting of the
air/fuel ratio, the fuel injection system is called a
"closed loop" system.
TSG‐416 Engine Controls
The GCP monitors signals from several sensors
in order to determine the fuel needs of the
engine. Fuel is delivered under one of several
conditions called "modes". All modes are
controlled by the GCP. Refer to "Open Loop and
Closed Loop Operation" for more information.

Fuel Injector

The Electronic Fuel Injection (EFI) fuel injector is
a solenoid operated device controlled by the
GCP. The GCP energizes the solenoid, which
opens a valve to allow fuel delivery.
The fuel is injected under pressure in a conical
spray pattern at the opening of the intake valve.
Excess fuel not used by the injectors passes
through the fuel pressure regulator before being
returned to the fuel tank.
A fuel injector which is stuck partly open will
cause a loss of fuel pressure after the engine is
shut down, causing long crank times.

Fuel Rail

The fuel rail is mounted to the top of the engine
and distributes fuel to the individual injectors.
Fuel is delivered to the fuel inlet tube of the fuel
rail by the fuel lines.

Fuel Filter

The fuel filter is an inline filter assembly. Refer to
Section 4 for information on relieving fuel
pressure, disconnecting fuel lines and fuel filter
replacement.
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