Fuel Rail Assembly . C2-4; Fuel Injector Assembly; Pressure Regulator Assembly - Pontiac Fiero 1988 Service Manual

6E3-C2-4 DRIVEABILITY A M D EMISSIONS - FUEL INJECTION f PORT)
8P0S32-AS
Figure C2-6 -
Fuel
Rail
Flow Diagram
PH FUEL INJECTOR
PH
INTAKE
M A N I F O L D
PH INTAKE VALVE
GO ELECTRICAL TERMINAL
GO "O" RING
flTl FUEL RAIL
4 S 1 0 1 0 - 6 E
Figure C2-7
- Fuel Injector Assembly
FUEL RAIL ASSEMBLY
The fuel rail (Figure C2-5) is mounted to the top of
the engine. It distributes fuel to the individual
injectors. Fuel is delivered to the input end of the rail
by the fuel lines, goes through the rail, then to the
pressure regulator. The regulator keeps the pressure
to the injectors at a constant pressure. Remaining fuel
is then returned to the fuel tank (see Figure C2-6).
COVER ASSEMBLY [T] VALVE SEAT
SPRING
FUEL RAIL
DIAPHRAGM
FUEL
RETURN
8
S
REGULATOR VALVE
VACUUM CONNECTION
SPRING RETAINER
8P 0968-AS
Figure €2-8 - Pressure Regulator Assembly
Fuel I n j e c t o r A s s e m b l y
The fuel injector is a solenoid operated device,,
controlled by the electronic control module (ECM),
that meters pressurized fuel to a single cylinder (see
Figure C2-7). The ECM energizes the solenoid, which
opens a valve to allow fuel delivery. The fuel, under
pressure, is injected in a conical spray pattern at the
opening of the intake valve. The fuel which is not
used by the injectors passes through the pressure
regulator before being returned to the fuel tank.
An injector that is stuck partly open would cause
loss of pressure after engine shut down.
Consequently, long cranking times would be noticed
on some engines. Dieseling could also occur because
some fuel could be delivered to the engine after the
ignition is turned "OFF".
Pressure R e g u l a t o r A s s e m b l y
The pressure regulator assembly (see Figure C2-8)
is a diaphragm-operated relief valve with Injector
pressure on one side and manifold pressure on the
other. The function of the regulator is to maintain a
constant pressure differential across the injectors at
all times, by controlling the flow In the return line
(i.e., a calibrated leak).
The pressure regulator is mounted at the end of
the fuel rail and Is not serviceable.