throttle sensor DODGE RAM 2003 Service Manual PDF

INSTALLATION
3.7L V-6
The Manifold Absolute Pressure (MAP) sensor is
mounted into the front of the intake manifold (Fig.
31). An o-ring is used to seal the sensor to the intake
manifold (Fig. 32).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears.
(3) Position sensor into manifold.(4) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(5) Connect electrical connector.
4.7L V-8
The MAP sensor is located on the front of the
intake manifold (Fig. 33). An o-ring seals the sensor
to the intake manifold (Fig. 32).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears.
(3) Position sensor into manifold.
(4) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(5) Connect electrical connector.
5.7L V-8
The Manifold Absolute Pressure (MAP) sensor is
mounted to the front of the intake manifold air ple-
num box (Fig. 34).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears.
(3) Position sensor into manifold.
(4) Rotate sensor 1/4 turn clockwise for installa-
tion.
(5) Connect electrical connector.
5.9L V-8
The MAP sensor is located on the front of the
throttle body (Fig. 36). An L-shaped rubber fitting is
used to connect the MAP sensor to throttle body (Fig.
37).
(1) Install rubber L-shaped fitting to MAP sensor.
(2) Position sensor to throttle body while guiding
rubber fitting over throttle body vacuum nipple.
(3) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(4) Install air resonator box.
8.0L V-10
The MAP sensor is mounted into the right upper
side of intake manifold (Fig. 38). A rubber gasket is
used to seal sensor to intake manifold. The rubber
gasket is part of sensor and is not serviced sepa-
rately.
(1) Check condition of sensor seal. Clean sensor
and lubricate rubber gasket with clean engine oil.
(2) Clean sensor opening in intake manifold.
(3) Install sensor into intake manifold.
(4) Install sensor mounting bolts. Refer to Torque
Specifications.
(5) Install electrical connector to sensor.
Fig. 37 MAP SENSOR L-SHAPED RUBBER FITTING
- 5.9L V-8
1 - MAP SENSOR
2 - RUBBER FITTING
3 - IDLE AIR PASSAGE
Fig. 38 MAP SENSOR LOCATION - 8.0L V-10
1 - MAP SENSOR
2 - MOUNTING BOLTS
3 - THROTTLE BODY
14 - 42 FUEL INJECTION - GASDR
MAP SENSOR (Continued)

INSTALLATION
Threads of new oxygen sensors are factory coated
with anti-seize compound to aid in removal.DO
NOT add any additional anti-seize compound to
threads of a new oxygen sensor.
(1) Install O2S sensor. Tighten to 30 N´m (22 ft.
lbs.) torque.
(2) Connect O2S sensor wire connector.
(3) Lower vehicle.
THROTTLE BODY
DESCRIPTION
The throttle body is located on the intake manifold.
Fuel does not enter the intake manifold through the
throttle body. Fuel is sprayed into the manifold by
the fuel injectors.
OPERATION
Filtered air from the air cleaner enters the intake
manifold through the throttle body. The throttle body
contains an air control passage controlled by an Idle
Air Control (IAC) motor. The air control passage is
used to supply air for idle conditions. A throttle valve
(plate) is used to supply air for above idle conditions.
5.7L V-8 Engine:
The throttle body on the 5.7L engine is an electri-
cally controlled unit. A mechanical cable is not used
to connect the throttle body to the accelerator pedal.
The Accelerator Pedal Position Sensor (APPS) along
with inputs from other sensors sets the throttle blade
to pre-determined positions.
Except 5.7L V-8 Engine:
Certain sensors are attached to the throttle body.
The accelerator pedal cable, speed control cable and
transmission control cable (when equipped) are con-
nected to the throttle body linkage arm.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the PCM.
REMOVAL
3.7L V-6
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the Powertrain Control Module (PCM).
(1) Remove air cleaner tube at throttle body.
(2) Disconnect throttle body electrical connectors
at IAC motor and TPS.(3) Remove all control cables from throttle body
(lever) arm. Refer to the Accelerator Pedal and Throt-
tle Cable section for removal/installation procedures.
(4) Disconnect necessary vacuum lines at throttle
body.
(5) Remove 3 throttle body mounting bolts (Fig.
41).
(6) Remove throttle body from intake manifold.
(7) Check condition of old throttle body-to-intake
manifold o-ring (Fig. 42).
4.7L V-8
(1) Remove air duct and air resonator box at throt-
tle body.
(2) Disconnect throttle body electrical connectors
at IAC motor and TPS (Fig. 43).
(3) Remove vacuum line at throttle body.
(4) Remove all control cables from throttle body
(lever) arm. Refer to Accelerator Pedal and Throttle
Cable.
(5) Remove three throttle body mounting bolts
(Fig. 43).
(6) Remove throttle body from intake manifold.
5.7L V-8
CAUTION: Do not use spray (carb) cleaners on any
part of the throttle body. Do not apply silicone lubri-
cants to any part of the throttle body.
Fig. 41 THROTTLE BODY MOUNTING BOLTS - 3.7L
V-6
1 - THROTTLE BODY
2 - MOUNTING BOLTS (3)
DRFUEL INJECTION - GAS 14 - 45
OXYGEN SENSOR (Continued)

(1) Remove air duct and air resonator box at throt-
tle body.
(2) Disconnect electrical connector at throttle body
(Fig. 44).
(3) Remove 4 throttle body mounting bolts (Fig.
44).
(4) Remove throttle body from intake manifold.(5) Check condition of throttle body o-ring (Fig.
45).
(6) If the throttle body has been changed, the fol-
lowing procedure must be performed:
(a) Disconnect negative battery cable from bat-
tery. Leave cable disconnected for approximately 90
seconds.
(b) Reconnect cable to battery.
(c) Turn ignition switch ON, but do not crank
engine.
(d) Leave ignition switch ON for a minimum of
10 seconds. This will allow PCM to learn throttle
body electrical parameters.
5.9L V-8
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the powertrain control module (PCM).
(1) Remove the air cleaner resonator tube.
(2) Disconnect throttle body electrical connectors
at MAP sensor, IAC motor and TPS (Fig. 46).
(3) Remove vacuum line at throttle body.
(4) Remove all control cables from throttle body
(lever) arm. Refer to the Accelerator Pedal and Throt-
tle Cable section of this group for additional informa-
tion.
Fig. 42 THROTTLE BODY O-RING - 3.7L V-6
1 - INTAKE MANIFOLD
2 - THROTTLE BODY O-RING
Fig. 43 THROTTLE BODY MOUNTING BOLTS - 4.7L
V-8
1 - MOUNTING BOLTS (3)
2 - THROTTLE BODY
3 - IAT SENSOR CONNECTOR
4 - IAC MOTOR CONNECTOR
5 - TPS CONNECTOR
Fig. 44 5.7L V-8 THROTTLE BODY
1 - THROTTLE BODY
2 - ELECTRICAL CONNECTOR
3 - SILICONE SEAL
4 - MOUNTING BOLTS (4)
14 - 46 FUEL INJECTION - GASDR
THROTTLE BODY (Continued)

(5) Remove four throttle body mounting bolts (Fig.
47).
(6) Remove throttle body from intake manifold.
(7) Discard old throttle body-to-intake manifold
gasket.8.0L V-10
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the powertrain control module (PCM).
(1) Remove air plenum resonator.
(2) Disconnect throttle body electrical connectors
at the IAC motor and TPS.
(3) Remove all control cables from throttle body
(lever) arm. Refer to the Accelerator Pedal and Throt-
tle Cable section of this group for additional informa-
tion.
(4) Remove four throttle body mounting nuts (Fig.
48).
(5) Remove throttle body from intake manifold.
(6) Discard old throttle body-to-intake manifold
gasket.
INSTALLATION
3.7L V-6
(1) Check condition of throttle body-to-intake man-
ifold o-ring. Replace as necessary.
(2) Clean mating surfaces of throttle body and
intake manifold.
(3) Install throttle body-to-intake manifold o-ring.
(4) Install throttle body to intake manifold.
(5) Install 3 mounting bolts. Tighten bolts to 12
N´m (105 in. lbs.) torque.
Fig. 45 5.7L V-8 THROTTLE BODY O-RING
1 - INTAKE MANIFOLD
2 - THROTTLE BODY O-RING
Fig. 46 SENSOR ELECTRICAL CONNECTORS - 5.9L
V-8
1 - MAP SENSOR
2 - IDLE AIR CONTROL MOTOR
3 - THROTTLE POSITION SENSOR
Fig. 47 THROTTLE BODY MOUNTING BOLTS - 5.9L
V-8
1 - THROTTLE BODY MOUNTING BOLTS (4)
2 - THROTTLE BODY
DRFUEL INJECTION - GAS 14 - 47
THROTTLE BODY (Continued)

5.7L V-8
The Throttle Control Cable on the 5.7L V-8 engine
connects the accelerator pedal to the Accelerator
Pedal Position Sensor (APPS). A separate mechanical
cable is not routed to the throttle body.
CAUTION: Be careful not to damage or kink cable
core wire (within cable sheathing) while servicing
accelerator pedal, cables or APPS.
(1) From inside vehicle, hold up accelerator pedal.
Remove plastic cable retainer and throttle cable core
wire from upper end of pedal arm (Fig. 1). The plas-
tic cable retainer snaps into pedal arm.
(2) Remove cable core wire at pedal arm.
(3) Remove APPS. Refer to Accelerator Pedal Posi-
tion Sensor (APPS) Removal / Installation.
(4) From inside vehicle, remove cable clip (Fig. 1).
(5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Remove cable housing at APPS bracket by
pressing on release tab with a small screwdriver.To
prevent cable housing breakage, press on tab
only enough to release cable from APPS
bracket.
5.9L V-8
CAUTION: Be careful not to damage or kink cable
core wire (within cable sheathing) while servicing
accelerator pedal or cables.
(1) From inside vehicle, hold up accelerator pedal.
Remove plastic cable retainer and throttle cable core
wire from upper end of pedal arm (Fig. 1). The plas-
tic cable retainer snaps into pedal arm.
(2) Remove cable core wire at pedal arm.
(3) Remove air resonator at throttle body.
(4) From inside vehicle, remove cable clip (Fig. 1).
(5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Disconnect cable from routing/holddown clip.
(7) Slip cable end rearward from pin on throttle
body (Fig. 53).
(8) Remove cable housing at throttle body mount-
ing bracket by pressing on release tab with a small
screwdriver (Fig. 54).To prevent cable housing
breakage, press on tab only enough to release
cable from bracket.Lift cable housing straight up
from bracket while pressing on release tab. Remove
throttle cable from vehicle.
Fig. 51 ACCELERATOR CABLE AT BELL CRANK -
4.7L V-8
1 - THROTTLE BODY
2 - SPEED CONTROL CABLE CONNECTOR
3 - OFF
4 - OFF
5 - ACCELERATOR CABLE CONNECTOR
6 - CABLE CAM
7 - BELLCRANK
Fig. 52 ACCELERATOR CABLE RELEASE TAB -
4.7L V-8
1 - ACCELERATOR CABLE
2 - PLASTIC CABLE MOUNT
3 - PRESS TAB FOR REMOVAL
4 - CABLE BRACKET
5 - SLIDE FOR REMOVAL
14 - 50 FUEL INJECTION - GASDR
THROTTLE CONTROL CABLE (Continued)

(4) From inside vehicle, install metal clip holding
cable to dashpanel (Fig. 1).
(5) From inside vehicle, slide throttle cable core
wire into opening (slot) in top of pedal arm.
(6) Push plastic cable retainer (clip) into pedal arm
opening until it snaps in place.
(7) Install air resonator tube to throttle body.
(8) Before starting engine, operate accelerator
pedal to check for any binding.
4.7L V-8
(1) Slide accelerator cable plastic mount into
bracket. Continue sliding until tab (Fig. 52) is
aligned to hole in mounting bracket.
(2) Route accelerator cable over top of cable cam.
(3) Connect cable end to throttle body bellcrank
pin (snaps on rearward).
(4) Slide rubber grommet away from plastic cable
housing.
(5) Install rubber grommet into dash panel until
seated.
(6) Push cable housing into rubber grommet and
through opening in dash panel.
(7) From inside vehicle, install clip holding cable
to dashpanel (Fig. 1).
(8) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.
(9) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(10) Snap cable into dashpanel routing clip.
(11) Install air resonator tube to throttle body.
(12) Before starting engine, operate accelerator
pedal to check for any binding.
5.7L V-8
(1) Attach cable to Accelerator Pedal Position Sen-
sor (APPS). Refer to APPS Removal / Installation.
(2) Push cable housing into rubber grommet and
through opening in dash panel.
(3) From inside vehicle, install clip holding cable
to dashpanel (Fig. 1).
(4) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.
(5) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(6) Before starting engine, operate accelerator
pedal to check for any binding.
(7) If necessary, use DRB IIItScan Tool to erase
any APPS Diagnostic Trouble Codes (DTC's) from
PCM.
5.9L V-8
(1) Slide accelerator cable plastic mount into throt-
tle body mounting bracket. Continue sliding until
release tab (Fig. 54) is aligned to hole in mounting
bracket.(2) Hold throttle in wide open position. While held
in this position, slide throttle cable pin into throttle
body bellcrank.
(3) Push cable housing into rubber grommet and
through opening in dash panel.
(4) From inside vehicle, install metal clip holding
cable to dashpanel (Fig. 1).
(5) From inside vehicle, slide throttle cable core
wire into opening (slot) in top of pedal arm.
(6) Push plastic cable retainer (clip) into pedal arm
opening until it snaps in place.
(7) Install air resonator tube to throttle body.
(8) Before starting engine, operate accelerator
pedal to check for any binding.
8.0L V-10
(1) Connect cable end socket to throttle body lever
ball (snaps on) (Fig. 55).
(2) Connect cable to throttle body mounting
bracket (push down and lock)
(3) Install the remaining cable housing end into
and through the dash panel opening (snaps into posi-
tion). The two plastic pinch tabs (Fig. 1) should lock
the cable to dash panel.
(4) From inside the vehicle, hold up the accelera-
tor pedal. Install the throttle cable core wire and
plastic cable retainer into and through the upper end
of the pedal arm (the plastic retainer is snapped into
the pedal arm). When installing the plastic retainer
to the accelerator pedal arm, note the index tab on
the pedal arm (Fig. 1). Align the index slot on the
plastic cable retainer to this index tab.
(5) Install air resonator tube to throttle body.
(6) Before starting engine, operate accelerator
pedal to check for any binding.
THROTTLE POSITION SENSOR
DESCRIPTION
The 3-wire Throttle Position Sensor (TPS) is
mounted on the throttle body and is connected to the
throttle blade shaft.
The 5.7L V-8 engine does not use a separate TPS
on the throttle body.
OPERATION
The 5.7L V-8 engine does not use a separate Throt-
tle Position Sensor (TPS) on the throttle body.
The 3±wire TPS provides the Powertrain Control
Module (PCM) with an input signal (voltage) that
represents the throttle blade position of the throttle
body. The sensor is connected to the throttle blade
shaft. As the position of the throttle blade changes,
the output voltage of the TPS changes.
14 - 52 FUEL INJECTION - GASDR
THROTTLE CONTROL CABLE (Continued)

The PCM supplies approximately 5 volts to the
TPS. The TPS output voltage (input signal to the
PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the TPS.
This will vary in an approximate range of from .26
volts at minimum throttle opening (idle), to 4.49 volts
at wide open throttle. Along with inputs from other
sensors, the PCM uses the TPS input to determine
current engine operating conditions. In response to
engine operating conditions, the PCM will adjust fuel
injector pulse width and ignition timing.
The PCM needs to identify the actions and position
of the throttle blade at all times. This information is
needed to assist in performing the following calcula-
tions:
²Ignition timing advance
²Fuel injection pulse-width
²Idle (learned value or minimum TPS)
²Off-idle (0.06 volt)
²Wide Open Throttle (WOT) open loop (2.608
volts above learned idle voltage)
²Deceleration fuel lean out
²Fuel cutoff during cranking at WOT (2.608 volts
above learned idle voltage)
²A/C WOT cutoff (certain automatic transmis-
sions only)
REMOVAL
3.7L V6
The Throttle Position Sensor (TPS) is mounted to
the throttle body (Fig. 56), or (Fig. 57).
(1) Remove air resonator tube at throttle body.
(2) Disconnect TPS electrical connector.
(3) Remove 2 TPS mounting screws.
(4) Remove TPS.
4.7L V-8
The TPS is located on the throttle body (Fig. 58).
(1) Remove air duct and tube at throttle body.
(2) Disconnect TPS electrical connector.
(3) Remove two TPS mounting bolts (screws) (Fig.
58).
(4) Remove TPS from throttle body.
5.7L V-8
The 5.7L V-8 engine does not use a separate Throt-
tle Position Sensor (TPS) on the throttle body.
5.9L V-8
The TPS is located on the side of the throttle body
(Fig. 59).
(1) Remove air intake tube at throttle body.
(2) Disconnect TPS electrical connector.
(3) Remove two TPS mounting bolts (Fig. 59).
(4) Remove TPS from throttle body.
8.0L V-10
The TPS is located on the side of the throttle body
(Fig. 60).
(1) Remove air plenum.
(2) Disconnect TPS electrical connector.
Fig. 56 TPS LOCATION - 3.7L V-6
1 - THROTTLE POSITION SENSOR (TPS)
2 - MOUNTING SCREWS
3 - IDLE AIR CONTROL MOTOR (IAC)
4 - MOUNTING SCREWS
Fig. 57 TPS INSTALLATION - 3.7 V-6
1 - THROTTLE BODY
2 - TPS
3 - THROTTLE BODY SHAFT
4 - SOCKET LOCATING TANGS
DRFUEL INJECTION - GAS 14 - 53
THROTTLE POSITION SENSOR (Continued)

(3) Remove two TPS mounting bolts (Fig. 60).
(4) Remove TPS from throttle body.
INSTALLATION
3.7L V-6
The Throttle Position Sensor (TPS) is mounted to
the throttle body (Fig. 56).
The throttle shaft end of throttle body slides into a
socket in TPS (Fig. 61). The TPS must be installed so
that it can be rotated a few degrees. (If sensor will
not rotate, install sensor with throttle shaft on other
side of socket tangs). The TPS will be under slight
tension when rotated.
(1) Install TPS and retaining screws.
(2) Tighten screws to 7 N´m (60 in. lbs.) torque.
(3) Connect TPS electrical connector to TPS.
(4) Manually operate throttle (by hand) to check
for any TPS binding before starting engine.
(5) Install air cleaner tube to throttle body.
4.7L V-8
The throttle shaft end of throttle body slides into a
socket in TPS (Fig. 62). The TPS must be installed so
that it can be rotated a few degrees. If sensor will
not rotate, install sensor with throttle shaft on other
side of socket tangs. The TPS will be under slight
tension when rotated.
(1) Install TPS and two retaining bolts.
(2) Tighten bolts to 7 N´m (60 in. lbs.) torque.
(3) Manually operate throttle control lever by hand
to check for any binding of TPS.
(4) Connect TPS electrical connector to TPS.
Fig. 58 TPS LOCATION - 4.7L
1 - THROTTLE BODY
2 - TPS
3 - IAC MOTOR
4 - IAT SENSOR
5 - MOUNTING SCREWS
Fig. 59 TPS LOCATION - 5.9L V-8
1 - THROTTLE POSITION SENSOR
2 - MOUNTING SCREWS
Fig. 60 TPS MOUNTING BOLTS - 8.0L V-10
1 - MOUNTING BOLTS (2)
2 - IDLE AIR CONTROL MOTOR
3 - THROTTLE POSITION SENSOR
4 - THROTTLE BODY
14 - 54 FUEL INJECTION - GASDR
THROTTLE POSITION SENSOR (Continued)

(5) Install air duct/air box to throttle body.
5.9L V-8
The throttle shaft end of the throttle body slides
into a socket in the TPS (Fig. 63). The TPS must be
installed so that it can be rotated a few degrees. If
sensor will not rotate, install sensor with throttle
shaft on other side of socket tangs. The TPS will be
under slight tension when rotated.
(1) Install TPS and two retaining bolts.
(2) Tighten bolts to 7 N´m (60 in. lbs.) torque.
(3) Manually operate throttle control lever by hand
to check for any binding of TPS.
(4) Connect TPS electrical connector to TPS.
(5) Install air intake tube.
8.0L V-10
The throttle shaft end of the throttle body slides
into a socket in the TPS (Fig. 63). The TPS must be
installed so that it can be rotated a few degrees. If
sensor will not rotate, install sensor with throttle
shaft on other side of socket tangs. The TPS will be
under slight tension when rotated.
(1) Install TPS and two retaining bolts. Refer to
Torque Specifications.
(2) Manually operate throttle control lever by hand
to check for any binding of TPS.
(3) Connect TPS electrical connector to TPS.
(4) Install air plenum.
Fig. 61 TPS INSTALLATION - 3.7L
1 - THROTTLE BODY
2 - TPS
3 - THROTTLE BODY SHAFT
4 - SOCKET LOCATING TANGS
Fig. 62 TPS INSTALLATION - 4.7L
1 - THROTTLE BODY
2 - LOCATING TANGS
3 - THROTTLE POSITION SENSOR
4 - SOCKET
5 - THROTTLE SHAFT
Fig. 63 TPS INSTALLATION - 5.9L V-8 AND 8.0L V-10
1 - THROTTLE BODY
2 - THROTTLE POSITION SENSOR
3 - THROTTLE SHAFT
4 - SOCKET LOCATING TANGS
DRFUEL INJECTION - GAS 14 - 55
THROTTLE POSITION SENSOR (Continued)

FUEL DELIVERY - DIESEL
DESCRIPTION - DIESEL FUEL SYSTEM
The fuel system used on the Cummins engine is an
electronically controlled, Bosch HPCR (High-Pressure
Common Rail) system. The HPCR system consists of
five main components:
²Electric Fuel Transfer (lift) Pump
²Fuel Pump/Gear Pump (attached to fuel injec-
tion pump)
²High-Pressure Fuel Injection Pump
²Fuel Injection Rail
²Fuel Injectors
Also to be considered as part of the overall fuel
system are:
²Accelerator Pedal
²Air Cleaner Housing/Element
²Fuel Drain Manifold (passage)
²Fuel Drain Valve (at filter)
²Fuel Filter/Water Separator
²Fuel Heater
²Fuel Heater Relay
²Fuel Level (gauge) Sending Unit
²Fuel Tank
²Fuel Tank Module (containing fuel gauge send-
ing unit and separate fuel filter located at bottom of
tank module)
²Fuel Tank Filler/Vent Tube Assembly
²Fuel Tank Filler Tube Cap
²Fuel Tubes/Lines/Hoses
²High-Pressure Fuel Injector Lines
²In-Tank Fuel Filter (at bottom of fuel tank mod-
ule)
²Low-Pressure Fuel Supply Lines
²Low-Pressure Fuel Return Line
²Overflow Valve
²Quick-Connect Fuel Line Fittings
²Throttle Cable
²Water Draining (maintenance)
²Water-In-Fuel (WIF) Sensor
The fuel injection pump supplies high pressure to
the fuel rail independent of engine speed. This high
pressure is then accumulated in the fuel rail. High
pressure fuel is constantly supplied to the injectors
by the fuel rail. The Engine Control Module (ECM)
controls the fueling and timing of the engine by actu-
ating the injectors.Fuel enters the system from the electric fuel trans-
fer (lift) pump, which is attached to the fuel filter
assembly. Fuel is forced through the fuel filter ele-
ment and then enters the Fuel Pump/Gear Pump,
which is attached to the rear of the fuel injection
pump. The Fuel Pump/Gear Pump is a low-pressure
pump and produce pressures ranging from 551.5 kpa
(80 psi) to 1241 kpa (180) psi. Fuel then enters the
fuel injection pump. Low pressure fuel is then sup-
plied to the FCA (Fuel Control Actuator).
The FCA is an electronically controlled solenoid
valve. The ECM controls the amount of fuel that
enters the high-pressure pumping chambers by open-
ing and closing the FCA based on a demanded fuel
pressure. The FPS (Fuel Pressure Sensor) on the fuel
rail provides the actual fuel pressure. When the
actuator is opened, the maximum amount of fuel is
being supplied to the fuel injection pump. Any fuel
that does not enter the injection pump is directed to
the overflow valve. The overflow valve regulates how
much excess fuel is used for lubrication of the pump
and how much is returned to the tank through the
drain manifold.
Fuel entering the injection pump is pressurized to
between 300 - 1600 bar by three radial pumping
chambers. The pressurized fuel is then supplied to
the fuel rail.
Some fuel system components are shown in.
WARNING: HIGH-PRESSURE FUEL LINES DELIVER
DIESEL FUEL UNDER EXTREME PRESSURE FROM
THE INJECTION PUMP TO THE FUEL INJECTORS.
THIS MAY BE AS HIGH AS 160,000 KPA (23,206
PSI). USE EXTREME CAUTION WHEN INSPECTING
FOR HIGH-PRESSURE FUEL LEAKS. INSPECT FOR
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD. HIGH FUEL INJECTION PRESSURE
CAN CAUSE PERSONAL INJURY IF CONTACT IS
MADE WITH THE SKIN.
Certain fuel system components can be found in
(Fig. 1), or (Fig. 2).
STANDARD PROCEDURE
STANDARD PROCEDURES - WATER DRAINING
AT FUEL FILTER
Refer to Fuel Filter/Water Separator removal/in-
stallation for procedures.
DRFUEL DELIVERY - DIESEL 14 - 57