2002 DODGE RAM PCM

FUEL DELIVERY - DIESEL
DESCRIPTION
DESCRIPTION - DIESEL FUEL DELIVERY
SYSTEM
The fuel system on the Cummins 24 valveÐTurbo
Diesel Engine uses anelectronically controlled
fuel injection pump with three control modules.
Also refer to the Powertrain Control Module (PCM)
or Engine Control Module sections.
Some fuel system components are shown in (Fig.
1).
The fuel delivery system consists of the:
²Accelerator pedal
²Air cleaner housing/element
²Fuel drain manifold (passage)
²Fuel filter/water separator
²Fuel heater
²Fuel heater relay
²Fuel transfer (lift) pump
²Fuel injection pump
²Fuel injectors
²Fuel heater temperature sensor
²Fuel tank
²Fuel tank filler/vent tube assembly²Fuel tank filler tube cap
²Fuel tank module containing the rollover valve,
fuel gauge sending unit (fuel level sensor) and a sep-
arate fuel filter located at bottom of tank module
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 fittings
²Throttle cable
²Water draining
OPERATION
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 120,000 KPA (17,405
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.
BR/BEFUEL DELIVERY - DIESEL 14 - 55

(d) Tighten sensor to 2±3 N´m (15±20 in. lbs.)
torque.
(e) Connect electrical connector to WIF sensor.
(f) Install fuel filter. Refer to previous steps.
(4)Fuel Heater Element:
(a) Do not install fuel filter until heater element
is installed.
(b) Position heater element into filter housing
(fingers downward). Lock fingers into housing.
(c) Install new o-ring to electrical connector
(where connector passes through filter housing).
Apply a light film of clean diesel oil to o-ring seal.
Press this connector into filter housing until it
snaps into heater element.
(d) Install temperature sensor housing and 2
mounting screws to fuel filter housing.
(e) Connect electrical connector.
(f) Install fuel filter. Refer to previous steps.
(5)Drain Valve:
(a) Install 2 new o-rings to valve and filter hous-
ing.
(b) Apply a light film of clean diesel oil to both
seals.
(c) Position valve to filter housing.
(d) Install 4 mounting screws and tighten to 3±5
N´m (30±40 in. lbs.) torque.
(e) Connect drain hose to drain valve.
(f) Install fuel filter. Refer to previous steps.
(6) Start engine and check for leaks.
FUEL HEATER
DESCRIPTION
The fuel heater assembly is located on the side of
the fuel filter housing (Fig. 18).
The heater/element assembly is equipped with a
temperature sensor (thermostat) that senses fuel
temperature. This sensor is attached to the fuel heat-
er/element assembly.
OPERATION
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation.
When the temperature is below 45  8 degrees F,
the temperature sensor allows current to flow to the
heater element warming the fuel. When the temper-
ature is above 75  8 degrees F, the sensor stops cur-
rent flow to the heater element.
Battery voltage to operate the fuel heater element
is supplied from the ignition switch and through the
fuel heater relay. Also refer to Fuel Heater Relay.
The fuel heater element and fuel heater relay
are not computer controlled.
The heater element operates on 12 volts, 300 watts
at 0 degrees F.
DIAGNOSIS AND TESTING - FUEL HEATER
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation.
NOTE: The fuel heater element, fuel heater relay
and fuel heater temperature sensor are not con-
trolled by the Powertrain Control Module (PCM).
A malfunctioning fuel heater can cause a wax
build-up in the fuel filter/water separator. Wax
build-up in the filter/separator can cause engine
starting problems and prevent the engine from rev-
ving up. It can also cause blue or white fog-like
exhaust. If the heater is not operating in cold tem-
peratures, the engine may not operate due to fuel
waxing.
The fuel heater assembly is located on the side of
the fuel filter housing (Fig. 19).
The heater assembly is equipped with a built-in
fuel temperature sensor (thermostat) that senses fuel
temperature. When fuel temperature drops below 45
degrees   8 degrees F, the sensor allows current to
flow to the built-in heater element to warm the fuel.
When fuel temperature rises above 75 degrees   8
degrees F, the sensor stops current flow to the heater
element (circuit is open).
Fig. 18 Fuel Heater Location
1 - FUEL HEATER AND TEMP. SENSOR
2 - FUEL FILTER/WATER SEPARATOR
3 - FUEL HEATER ELECTRICAL CONNECTOR
14 - 66 FUEL DELIVERY - DIESELBR/BE
FUEL FILTER / WATER SEPARATOR (Continued)

DIAGNOSIS AND TESTING - FUEL HEATER
RELAY
The fuel heater relay is located in the Power Dis-
tribution Center (PDC). Refer to label under PDC
cover for relay location.
To test the fuel heater, refer to Fuel Heater Test.
To test the heater relay only, refer to following:
The relay terminal numbers from (Fig. 21) can be
found on the bottom of the relay.
²Terminal number 30 is connected to battery volt-
age and can be switched or B+ (hot) at all times.
²The center terminal number 87A is connected (a
circuit is formed) to terminal 30 in the de-energized
(normally OFF) position.
²Terminal number 87 is connected (a circuit is
formed) to terminal 30 in the energized (ON) posi-
tion. Terminal number 87 then supplies battery volt-
age to the component being operated.
²Terminal number 86 is connected to a switched
(+) power source.
²Terminal number 85 is grounded by the power-
train control module (PCM).
TESTING
(1) Remove relay before testing.
(2) Using an ohmmeter, perform a resistance test
between terminals 85 and 86. Resistance value
(ohms) should be 75  5 ohms for resistor equipped
relays.
(3)
Connect the ohmmeter between terminals number
87A and 30. Continuity should be present at this time.
(4) Connect the ohmmeter between terminals num-
ber 87 and 30. Continuity should not be present at
this time.
(5) Use a set of jumper wires (16 gauge or small-
er). Connect one jumper wire between terminal num-
ber 85 (on the relay) to the ground side (-) of a 12
Volt power source.
(6) Attach the other jumper wire to the positive
side (+) of a 12V power source. Do not connect this
jumper wire to relay at this time.
CAUTION: Do not allow the ohmmeter to contact
terminals 85 or 86 during these tests. Damage to
ohmmeter may result.
Fig. 21 Relay Terminals
14 - 68 FUEL DELIVERY - DIESELBR/BE
FUEL HEATER RELAY (Continued)

OPERATION
The Bosch VP44 fuel injection pump (Fig. 25) is a
solenoid-valve controlled-radial-piston-distributor
type pump.The injection pump is driven by the engine cam-
shaft. A gear on the end of the pump shaft meshes
with the camshaft gear. The pump is timed to the
engine. The VP44 is controlled by an integral (and
non-serviceable) Fuel Pump Control Module (FPCM)
(Fig. 24). The FPCM can operate the engine as an
engine controller if a Crankshaft Position Sensor
(CKP) signal is not present.
Fuel from the transfer (lift) pump enters the VP44
where it is pressurized and then distributed through
high-pressure lines to the fuel injectors. The VP44 is
cooled by the fuel that flows through it. A greater
quantity of fuel is required for cooling the VP44 than
what is necessary for engine operation. Because of
this, approximately 70 percent of fuel entering the
pump is returned to the fuel tank through the over-
flow valve and fuel return line. Refer to Overflow
Valve Description/Operation for additional informa-
tion.
The VP44 is not self-priming. At least two fuel
injectors must be bled to remove air from the system.
When servicing the fuel system, disconnecting compo-
nents up to the pump will usually not require air
bleeding from the fuel system. However, removal of
the high-pressure lines, removal of the VP44 pump,
or allowing the vehicle to completely run out of fuel,
will require bleeding air from the high-pressure lines
at the fuel injectors.
VP44 timing is matched to engine timing by an off-
set keyway that fits into the pump shaft. This key-
way has a stamped number on it that is matched to
a number on the VP44 pump (each keyway is cali-
brated to each pump).
When removing/installing the VP44, the same
numbered keyway must always be installed.
Also, the arrow on the top of the keyway should
be installed pointed rearward towards the
pump.
Because of electrical control, the injection pump
high and low idle speeds are not adjustable. Also,
adjustment of fuel pump timing is not required and
is not necessary.
DIAGNOSIS AND TESTINGÐFUEL INJECTION
PUMP TIMING
With the Bosch VP44 injection pump, there are no
mechanical adjustments needed for fuel injection tim-
ing. All timing and fuel adjustments are made by the
Engine Control Module (ECM). However, if a Diag-
nostic Trouble Code (DTC) has been stored indicating
an ªengine sync errorº or a ªstatic timing errorº, per-
form the following.
Fig. 24 Fuel Injection Pump Location
1 - FPCM ELECTRICAL CONNECTOR
2 - HIGH-PRESSURE FUEL LINES
3 - FITTINGS
4 - FUEL INJECTION PUMP
5 - FPCM
Fig. 25 Bosch VP44 Fuel Injection Pump
1 - BOSCH VP44 PUMP
14 - 70 FUEL DELIVERY - DIESELBR/BE
FUEL INJECTION PUMP (Continued)

(1) Remove hose clamp and crankcase vent hose at
crankcase breather (Fig. 26). Remove crankcase
breather from gear cover. Breather threads into
cover.
(2) Remove injection pump nut and washer (Fig.
27). Locate keyway behind washer.
(3) Be sure keyway aligning fuel injection pump
shaft to injection pump gear is in proper position and
pump gear has not slipped on pump shaft.
The following steps will require removing timing
gear cover to gain access to timing gears. Refer to
Group 9, Engines for procedures.
(4) Use a T-type puller to separate injection pump
gear from pump shaft.
(5) Be sure keyway has been installed with arrow
pointed torearof pump (Fig. 28).
(6)Pump timing has been calibrated to pump
keyway. Be sure 3±digit number on pump key-
way (Fig. 28) matches 3±digit number on fuel
injection pump data plate. Plate is located on
side of injection pump (Fig. 29). Twenty±one dif-
ferent calibrated keyways/pumps are available.
(7) Verify timing marks on crank, cam and pump
are aligned (Fig. 30).
(8) Perform necessary gear alignment/repairs as
needed.
(9) Install crankcase breather to gear cover. Install
hose clamp and crankcase vent hose to breather (Fig.
26).
(10) After repairs are completed, erase DTC using
DRB Scan Tool.
REMOVAL
CAUTION: Refer to Cleaning Fuel System Parts.
(1) Disconnect both negative battery cables at both
batteries. Cover and isolate ends of cables.
(2) Thoroughly clean fuel lines at cylinder head
and injection pump ends. Thoroughly clean fuel injec-
tion pump and supply/return lines at side of pump.
(3) Disconnect 9±way electrical connector at Fuel
Pump Control Module (FPCM) (Fig. 31).
(4) Remove fuel return line at side of injection
pump by removing overflow valve (Fig. 32). Place rag
beneath overflow valve to catch excess fuel.
(5) Remove fuel supply line at side of injection
pump by removing banjo bolt (Fig. 32). Also remove
same line at top of fuel filter housing (banjo bolt).
(6) Remove all high-pressure fuel lines, intake air
tube, accelerator pedal position sensor, air intake
housing, engine oil dipstick tube, wiring clips, electri-
cal cables at intake heaters and engine lifting
bracket. Refer to High-Pressure Fuel Line Removal/
Installation. All of these items are covered in this
procedure.
(7) Remove hose clamp at crankcase vent hose
(Fig. 33) and remove hose from canister.
(8) Remove (unscrew) canister (Fig. 33) from gear
cover.
Fig. 30 Checking Fuel Injection Pump Gear Timing
1 - PUMP SHAFT
2 - KEYWAY
3 - PUMP GEAR
4 - CAM GEAR
5 - CRANKSHAFT GEAR
Fig. 31 FPCM 9±Way Connector
1 - FPCM ELECTRICAL CONNECTOR
2 - HIGH-PRESSURE FUEL LINES
3 - FITTINGS
4 - FUEL INJECTION PUMP
5 - FPCM
14 - 72 FUEL DELIVERY - DIESELBR/BE
FUEL INJECTION PUMP (Continued)

The machined tapers on both injection pump
shaft and injection pump gear (Fig. 42) must be
absolutely dry, clean and free of any dirt or oil
film. This will ensure proper gear-to-shaft tight-
ening.
(5) Clean pump gear and pump shaft at machined
tapers (Fig. 42) with an evaporative type cleaner
such as brake cleaner.
Keyway Installation:
(6) The pump/gear keyway has an arrow and a
3±digit number stamped at top edge (Fig. 41). Posi-
tion keyway into pump shaft witharrow pointed to
rear of pump.Also be sure 3±digit number stamped
to top of keyway is same as 3±digit number stamped
to injection pump data plate (Fig. 43). If wrong key-
way is installed, a diagnostic trouble code may be
set.
(7) Position pump assembly to mounting flange on
gear cover while aligning injection pump shaft
through back of injection pump gear. When installing
pump, dowel (Fig. 42) on mounting flange must align
to hole in front of pump.(8) After pump is positioned flat to mounting
flange, install four pump mounting nuts and tighten
finger tight only. Do not attempt a final tightening at
this time.Do not attempt to tighten (pull) pump
to gear cover using mounting nuts. Damage to
pump or gear cover may occur. The pump must
be positioned flat to its mounting flange before
attempting to tighten mounting nuts.
(9) To prevent damage or cracking of components,
tighten nuts/bolts in the following sequence:
(a) Install injection pump shaft washer and nut
to pump shaft. Tighten nutfinger tight only.
(b) Install 2 rear/lower pump mounting bolts
finger tight only.
(c) Do preliminary tightening of injection pump
shaft nut to 30 N´m (15±22 ft. lbs.) torque.This is
not the final torque.
(d) Tighten 4 pump mounting nuts to 43 N´m
(32 ft. lbs.) torque.
(e) Tighten 2 rear/lower pump bracket-to-pump
bolts 24 N´m (18 ft. lbs.) torque.
(f) Do final tightening of injection pump shaft
nut to 170 N´m (125 ft. lbs.) torque. Use barring
tool to prevent engine from rotating when tighten-
ing gear.
(10) Install canister (Fig. 33) to gear cover.
(11) Install crankcase vent hose (Fig. 33) to canis-
ter and install hose clamp.
(12) Using new gaskets, install fuel return line
and overflow valve to side of injection pump (Fig. 32).
Tighten overflow valve to 24 N´m (18 ft. lbs.) torque.
(13) Using new gaskets, install fuel supply line to
side of injection pump and top of fuel filter housing
(Fig. 32). Tighten banjo bolts to 24 N´m (18 ft. lbs.)
torque.
(14) Install all high-pressure fuel lines, intake air
tube, accelerator pedal position sensor, air intake
housing, engine oil dipstick tube, wiring clips, electri-
cal cables at intake heaters and engine lifting
bracket. Refer to High-Pressure Fuel Line Removal/
Installation. All of these items are covered in this
procedure.
(15) Connect 9±way electrical connector to Fuel
Pump Control Module (FPCM) (Fig. 31).
(16) Connect both negative battery cables to both
batteries.
(17) Bleed air from fuel system.(Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY - STANDARD
PROCEDURE).
(18) Check system for fuel or engine oil leaks.
Fig. 43 Injection Pump Data Plate Location
1 - PUMP DATA PLATE
14 - 76 FUEL DELIVERY - DIESELBR/BE
FUEL INJECTION PUMP (Continued)

FUEL INJECTION PUMP DATA
PLATE
SPECIFICATIONS
FUEL INJECTION PUMP DATA PLATE
Pertinent information about the fuel injection
pump is machined into a boss on the drivers side of
the fuel injection pump (Fig. 44).
FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel tank module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel tank module on diesel powered models
has 3 different circuits (wires). Two of these circuits
are used at the fuel gauge sending unit for fuel
gauge operation. The other wire is used for a ground.
The diesel engine does not have a fuel tank module
mounted electric fuel pump. The electric fuel pump
(fuel transfer pump) is mounted to the engine.
For Fuel Gauge Operation:A constant input
voltage source of about 12 volts (battery voltage) is
supplied to the resistor track on the fuel gauge send-
ing unit. This is fed directly from the Powertrain
Control Module (PCM).NOTE: For diagnostic pur-
poses, this 12V power source can only be veri-
fied with the circuit opened (fuel tank module
electrical connector unplugged). With the con-
nectors plugged, output voltages will vary from
about .6 volts at FULL, to about 7.0 volts at
EMPTY.The resistor track is used to vary the volt-
age (resistance) depending on fuel tank float level. As
fuel level increases, the float and arm move up,
which decreases voltage. As fuel level decreases, the
float and arm move down, which increases voltage.
The varied voltage signal is returned back to the
PCM through the sensor return circuit.
Both of the electrical circuits between the fuel
gauge sending unit and the PCM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the PCM, the PCM
will interpret the resistance (voltage) data and send
a message across the multi-plex bus circuits to the
instrument panel cluster. Here it is translated into
the appropriate fuel gauge level reading. Refer to
Instrument Panel for additional information.
FUEL LINES
DESCRIPTION
DESCRIPTION
All fuel lines up to the fuel injection pump are con-
sidered low-pressure. This includes the fuel lines
from: the fuel tank to the fuel transfer pump, and
the fuel transfer pump to the fuel injection pump.
The fuel return lines, the fuel drain manifold and the
fuel drain manifold lines are also considered low-
pressure lines. High-pressure lines are used between
the fuel injection pump and the fuel injectors. Also
refer to High-Pressure Fuel Lines Description/Opera-
tion.
Fig. 44 Fuel Injection Pump Data Plate Location
1 - PUMP DATA PLATE
BR/BEFUEL DELIVERY - DIESEL 14 - 77

(14) Remove engine lifting bracket at rear of
intake manifold (2 bolts) (Fig. 54).
(15) Remove bolts from all fuel injection line sup-
port brackets at intake manifold.
(16) Place shop towels around fuel lines at fuel
injectors. Do not allow fuel to drip down side of
engine.CAUTION: WHEN LOOSENING OR TIGHTENING
HIGH-PRESSURE FITTINGS AT INJECTION PUMP,
USE A BACK-UP WRENCH ON DELIVERY VALVE AT
PUMP. DO NOT ALLOW DELIVERY VALVE TO
ROTATE.
(17) Loosen high-pressure line fittings at injection
pump (Fig. 55) beginning with cylinders 1, 2 and 4.
(18) Loosen high-pressure lines at cylinder head
for cylinders 1, 2 and 4 (Fig. 54).
(19) Carefully remove front line bundle from
engine.Do not bend lines while removing.While
removing front line bundle, note line position.
(20) Loosen high-pressure lines at injection pump
beginning with cylinders 3, 5 and 6.
(21) Loosen high-pressure lines at cylinder head
for cylinders 3, 5 and 6 (Fig. 54).
(22) Carefully remove rear line bundle from
engine.Do not bend lines while removing.While
removing rear line bundle, note line position.
INSTALLATION
High-pressure lines are used between the fuel
injection pump and the fuel injectors only. All high-
pressure fuel lines are of the same length and inside
diameter. Correct high-pressure fuel line usage and
installation is critical to smooth engine operation.
Fig. 53 Intake Manifold Air Heater (Elements)
1 - AIR HEATER ELEMENTS
2 - LOWER GASKET
3 - BLOCK
4 - UPPER GASKET
Fig. 54 High-Pressure Fuel Lines
Fig. 55 High Pressure Lines at Fuel Injection Pump
1 - FPCM ELECTRICAL CONNECTOR
2 - HIGH-PRESSURE FUEL LINES
3 - FITTINGS
4 - FUEL INJECTION PUMP
5 - FPCM
BR/BEFUEL DELIVERY - DIESEL 14 - 81
FUEL LINES (Continued)