Dodge RAM TRUCK 1500 1995 Service Manual page 1100

14 -18 FUEL DELIVERY SYSTEM—DIESEL ENGINE
B R
HIGH
PRESSURE
FUEL LINE
(6)
FRONT OF ENGINE
AIR TEMPERATURE
SENSOR
J 9 1 1 4 - 7 4 ^
Fig. 11 Fuel Injectors—Typical
the combustion chamber is stopped. Exhaust gases
are prevented from entering the injector nozzle by
the needle valve.
For diagnosis, refer to the Diesel Engine—General
Diagnosis section of this group.
For removal and installation procedures, refer to
the Diesel Engine—Component Removal/Installation
section of this group.
FUEL SHUTDOWN SOLENOID
The fuel shutdown solenoid and fuel shut­
down solenoid relay are not controlled by the
powertrain control module (PCM).
The fuel shutdown (shut-off) solenoid is used to
electrically shut off the diesel fuel supply to the high-
pressure fuel injection pump. The solenoid is
mounted to the side of the pump and is connected to
the pump with a lever (Figs. 1 or 12).
The solenoid controls starting and stopping of the
engine regardless of the position of the accelerator
pedal. When the ignition switch is off, the solenoid
plunger is spring loaded (down) in the shutdown po­
sition (Fig. 13) and fuel is shut off to the injection
pump.
Two different coils are located within the solenoid
and a three-wire pigtail wire harness is attached to
the solenoid.
When the ignition switch is turned to the CRANK
(starter engaged) position, high-amperage current
(approximately 40 amps at 12 volts) is supplied to
one of the coils in the shutdown solenoid from the
fuel shutdown solenoid relay. This high-amperage
current allows the solenoid shaft to pull up on the in­
jection pump lever. The injection pump shutdown le­
ver is then positioned to the run position (Fig. 13).
When the ignition key is released to the ON posi­
tion, a low-amperage current is supplied to the other
coil in the solenoid. This is used to hold the solenoid
SENSOR
ELECTRICAL
CONNECTOR
INTAKE
MANIFOLD
(UPPER HALF)
FUEL
SHUTDOWN
SOLENOID
SOLENOID
ELECTRICAL
CONNECTOR
J9414-93
Fig. 12 Fuel Shutdown Solenoid Location
shaft in the up position. Accelerator pedal position
then controls fuel lever position for fuel control at the
injection pump.
SHUTDOWN
POSITION
RUN POSITION
FUEL
SHUTDOWN
SOLENOID
J9414-80
Fig. 13 Fuel Shutdown Solenoid Positions
Voltage to operate the solenoid is supplied from the
ignition switch and through the fuel shutdown sole­
noid relay (Fig. 14) (also refer to Fuel Shutdown So­
lenoid Relay).
For solenoid diagnosis, refer to Fuel Shutdown So­
lenoid in the Diesel Engine—General Diagnosis sec­
tion of this group.
If the shutdown solenoid is being replaced, its shaft