Dodge Ram Truck 1500-2500-3500. Manual — part 1480

a. Install new o-ring seal to WIF sensor.

b. Apply a light film of clean oil to o-ring seal.

c. Install sensor into housing.

d. Tighten sensor to 2.5 N·m (25 in. lbs.) torque.

e. Connect electrical connector to WIF sensor.

4. Fuel Heater Element:

a. Install fuel heater into fuel filter housing.

b. Install fuel heater thermostat into fuel filter housing.

c. Install fuel heater mounting screws and tighten to 1-1.5 N·m (13 in. lbs.) torque.

d. Connect electrical connector to fuel heater thermostat.

e. Install new filter cover O-ring onto fuel filter housing cover and lubricate with clean engine oil.

f. Tighten fuel filter housing cover (lid) to 34 N·m (25 ft. lbs.).

5. Drain Valve:

a. Install 2 new o-rings to valve.

b. Lubricate with silicon grease.

c. Install fuel drain valve.

d. Install 4 mounting screws and tighten to 1–1.5 N·m (8–13 in. lbs.) torque.

e. Connect drain hose to drain valve.

6. Start engine and check for leaks.

HEATER-FUEL

DESCRIPTION

The fuel heater assembly is located on the side of the fuel filter housing and internal to the fuel filter housing .

The heater/element assembly is equipped with a temperature sensor (thermostat) that senses fuel temperature. This
sensor is attached to the fuel heater/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 ele-
ment warming the fuel. When the temperature is above 75 ±8 degrees F, the sensor stops current 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 con-
trolled.

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 controlled by
the Engine Control Module (ECM).

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 revving up. It can also cause blue or
white fog-like exhaust. If the heater is not operating in cold temperatures, the engine may not operate due to fuel
waxing.

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FUEL DELIVERY - DIESEL

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The fuel heater assembly is located on the side of fuel filter housing.

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 built-in heater
element to warm fuel. When fuel temperature rises above 75 degrees ± 8 degrees F, the sensor stops current flow
to heater element (circuit is open).

Voltage to operate fuel heater element is supplied from ignition switch, through fuel heater relay (also refer to Fuel
Heater Relay), to fuel temperature sensor and on to fuel heater element.

The heater element operates on 12 volts, 300 watts at 0 degrees F. As temperature increases, power requirements
decrease.

A minimum of 7 volts is required to operate the fuel heater. The resistance value of the heater element is less than
1 ohm (cold) and up to 1000 ohms warm.

TESTING

1. Disconnect electrical connector from thermostat.

Ambient temperature must be below the circuit close temperature. If necessary, induce this ambient temperature by
placing ice packs on thermostat to produce an effective ambient temperature below circuit close temperature.

Measure resistance across two pins. Operating range is 0.3 — 0.45 Ohms.

2. If resistance is out of range, remove thermostat and check resistance across terminal connections of heater. The

heater can be checked at room temperature. Operating range is 0.3 - 0.45 Ohms.

3. Replace heater if resistance is not within operating range.

4. If heater is within operating range, replace heater thermostat.

REMOVAL

REMOVAL/INSTALLATION

The fuel heater/element/sensor assembly is located inside of the fuel filter housing. Refer to Fuel Filter/Water Sep-
arator Removal/Installation for procedures.

RELAY - FUEL HEATER

DESCRIPTION

The fuel heater relay is located in Power Distribution
Center (PDC) (8). Refer to label on inside of PDC
cover for relay location.

OPERATION

Battery voltage to operate the fuel heater element is supplied from the ignition switch through the fuel heater relay.
The fuel heater element and fuel heater relay are not computer controlled.

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FUEL DELIVERY - DIESEL

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REMOVAL

The fuel heater relay is located in the Power Distribu-
tion Center (PDC) (8). Refer to label under PDC cover
for relay location.

1. Remove PDC cover.

2. Remove relay from PDC.

3. Check condition of relay terminals and PDC con-

nector terminals for damage or corrosion. Repair if
necessary before installing relay.

4. Check for pin height (pin height should be the

same for all terminals within the PDC connector).
Repair if necessary before installing relay.

INSTALLATION

The fuel heater relay is located in the Power Distribution Center (PDC). Refer to label under PDC cover for relay
location.

1. Install relay to PDC.

2. Install cover to PDC.

PUMP - FUEL INJECTION

DESCRIPTION

A Robert Bosch high-pressure fuel injection pump is used. The pump is attached to the back of the timing gear
cover at the left / rear side of the engine.

OPERATION

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 actuating the injectors.

Fuel enters the system from the electric fuel transfer (lift) pump, which is located in the fuel tank. Fuel is forced
through the fuel filter element 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 supplied 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 opening 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 cascade overflow valve. The cascade 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 (4351-23206 psi) by three radial pumping
chambers. The pressurized fuel is then supplied to the fuel rail.

DIAGNOSIS AND TESTING - FUEL INJECTION PUMP TIMING

With the Bosch injection pump, there are no mechanical adjustments needed or necessary to accomplish fuel injec-
tion timing. All timing and fuel adjustments are electrically made by the engine mounted Engine Control Module
(ECM).

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REMOVAL

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.

1. Disconnect both negative battery cables at both

batteries. Cover and isolate ends of both cables.

2. Remove intake manifold air intake tube (above

injection pump) and its rubber connector hose (2).

3. Remove fan shroud.

4. Remove fan assembly.

5. Remove accessory drive belt.

6. Thoroughly clean the rear of injection pump, and

attachment points for its 3 fuel lines. Also clean the
opposite ends of these same 3 lines at their attach-
ment points.

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FUEL DELIVERY - DIESEL

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