Dodge Ram Truck 1500-2500-3500. Manual — part 1481

7. Disconnect Fuel Control Actuator (FCA) electrical

connector (3) at rear of injection pump.

CAUTION: Whenever a fuel line fitting is con-
nected to a secondary fitting, always use a
back-up wrench on the secondary fitting. Do not
allow the secondary fitting to rotate.

8. Remove fuel line (injection pump-to-fuel pressure

limiting valve).

9. Remove fuel line (injection pump-to-fuel rail). Use

back-up wrench on fitting at fuel pump.

10. Remove fuel line (injection pump-to-fuel filter

housing).

11. Remove fuel pump drive gear access cover (plate)

with a 3/8” drive ratchet. Plate (2) is threaded to
timing gear cover.

12. Remove fuel pump drive gear mounting nut and

washer.

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13. Attach C3428B, or L4407A (or equivalent) gear

puller (2) to pump drive gear with 2 bolts, and
separate gear from pump (a keyway is not used
on this particular injection pump). Leave drive
gear hanging loose within timing gear cover.

14. Remove 3 injection pump mounting nuts (6) , and remove pump from engine.

INSTALLATION

CAUTION: Cleanliness cannot be overemphasized when handling or replacing diesel fuel system compo-
nents. This especially includes the fuel injectors, high-pressure fuel lines and fuel injection pump. Very tight
tolerances are used with these parts. Dirt contamination could cause rapid part wear and possible plugging
of fuel injector nozzle tip holes. This in turn could lead to possible engine misfire. Always wash/clean any
fuel system component thoroughly before disassembly and then air dry. Cap or cover any open part after
disassembly. Before assembly, examine each part for dirt, grease or other contaminants and clean if nec-
essary. When installing new parts, lubricate them with clean engine oil or clean diesel fuel only.

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1. Inspect pump mounting surfaces at pump and mounting flange for nicks, cuts or damage. Inspect o-ring surfaces

for nicks, cuts or damage.

2. Clean injection pump mounting flange at gear housing. Also clean front of injection pump.

3. Install new rubber o-ring into machined groove at pump mounting area.

4. Apply clean engine oil to injection pump o-ring only.

The machined tapers on both injection pump shaft and injection pump gear must be absolutely dry, clean
and free of any dirt or oil film. This will ensure proper gear-to-shaft tightening.

5. Clean pump gear and pump shaft at machined tapers with an evaporative type cleaner such as brake cleaner.

6. Position injection pump to mounting flange on gear housing while aligning injection pump shaft through back of

injection pump gear.

7. After pump is positioned flat to mounting flange, install 3 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 housing 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 3 mounting nuts.

8. To prevent damage or cracking of components, install and tighten nuts in the following sequence:

a. Install injection pump shaft washer and nut to pump shaft. Tighten nut finger tight only.

b. Do preliminary (light) tightening of injection pump shaft nut.

c. Tighten 3 injection pump mounting nuts to 24 N·m (18 ft. lbs.).

d. Do a final tightening of pump shaft nut to 105 N·m (77 ft. lbs.).

9. Install drive gear access cover (plate) using a 3/8” drive ratchet. Plate is threaded to timing gear cover. Tighten

to 8 N·m (71 in. lbs.) torque.

10. Install fuel line (injection pump-to-pressure limiting valve). Tighten bolts to 24 N·m (18 ft. lbs.) torque.

11. Install fuel line (injection pump-to-fuel rail).

a. Tighten fitting at fuel pump to 37 N·m (27 ft. lbs.) torque. Use a back-up wrench.

b. Tighten fitting at fuel rail to 37 N·m (27 ft. lbs.) torque.

12. Install fuel line (injection pump-to-fuel filter housing). Tighten to 24 N·m (18 ft. lbs.) torque.

13. Connect Fuel Control Actuator (FCA) electrical connector to rear of injection pump.

14. Install intake manifold air intake tube (above injection pump). Tighten clamps.

15. Install accessory drive belt.

16. Install cooling fan shroud.

17. Install cooling fan assembly.

18. Connect both negative battery cables to both batteries.

19. Check system for fuel or engine oil leaks.

SENSOR - FUEL LEVEL SENDING UNIT

DESCRIPTION

The fuel gauge sending unit (fuel level sensor) is attached to the side of the fuel pump module. The sending unit
consists of a float, an arm, and a variable resistor track (card). The fuel transfer (lift) pump is also attached to the
fuel pump module.

OPERATION

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 sending unit. This is fed directly from the Engine Control Module (ECM). NOTE: For
diagnostic purposes, this 12V power source can only be verified with the circuit opened (fuel tank module
electrical connector unplugged). With the connectors 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 voltage (resistance) depending on fuel
tank float level. As fuel level increases, the float and arm move up, which decreases voltage. As fuel level

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decreases, the float and arm move down, which increases voltage. The varied voltage signal is returned back to the
ECM through the sensor return circuit.

Both of the electrical circuits between the fuel gauge sending unit and the ECM are hard-wired (not multi-plexed).
After the voltage signal is sent from the resistor track, and back to the ECM, the ECM 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.

REMOVAL

REMOVAL/INSTALLATION

For diesel removal and installation procedures, refer to the gas section of Fuel System/Fuel Delivery. See Fuel
Level Sending Unit/Sensor Removal/Installation.

LINES - FUEL

DESCRIPTION

Low-Pressure Lines Are:

•

the fuel supply line from fuel tank to fuel filter housing.

•

the fuel return line back to fuel tank.

•

the fuel drain (manifold) line at rear of cylinder head.

•

the fuel supply line from fuel filter to fuel injection pump.

•

the fuel injection pump return line.

High-Pressure Lines Are:

•

the fuel line from fuel injection pump to fuel rail.

•

the 6 fuel lines from fuel rail up to injector connector tubes

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-PRES-
SURE FUEL LEAKS WITH A SHEET OF CARDBOARD. HIGH FUEL INJECTION PRESSURE CAN CAUSE PER-
SONAL INJURY IF CONTACT IS MADE WITH THE SKIN.

OPERATION

High-Pressure Lines

CAUTION: The high-pressure fuel lines must be held securely in place in their holders. The lines cannot
contact each other or other components. Do not attempt to weld high-pressure fuel lines or to repair lines
that are damaged. If lines are ever kinked or bent, they must be replaced. Use only the recommended lines
when replacement of high-pressure fuel line is necessary.

High-pressure fuel lines deliver fuel (under pressure) of up to approximately 160,000 kPa (23,206 PSI) from the
injection pump to the fuel injectors. The lines expand and contract from the high-pressure fuel pulses generated
during the injection process. 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.

WARNING: 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.

DIAGNOSIS AND TESTING - HIGH-PRESSURE FUEL LINE LEAKS

High-pressure fuel line leaks can cause starting problems and poor engine performance.

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