2006 DODGE RAM SRT-10 engine

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 fuel temperature is below 45° ±8 F (7°C), the temperature sensor allows current to flow to the heater
element warming the fuel. When the fuel temperature is above 75° ±8 F (24°C), 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 a solid stated
device in the IPM.The fuel heater element and
solid state device in IPMinstead offuel heater relayare not
computer controlled.
The heater element operates on 12 volts, 300 watts at 0° F (-18° C).
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,
solid state device in IPMinstead offuel heater relayand fuel heater tem-
perature 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.
The fuel heater assembly is located on the side of fuel filter housing and internal to the 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° ± 8° F (7° C), the sensor allows current to flow to built-in heater element
to warm fuel. When fuel temperature rises above 75 °± 8° F (24° C), the sensorstops current flow to heater ele-
ment (circuit is open).
Voltage to operate fuel heater element is supplied from ignition switch, through
solid state device in IPM,tofuel
temperature sensor and on to fuel heater element.
The heater element operates on 12 volts, 300 watts at 0 °F (-18° C). 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.

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
housing at the left /front 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 producepressures ranging from 551.5 kpa
(80 psi) to 1241 kpa (180) psi. Fuel then enters the fuel injection pump. Lowpressure 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 neededor necessary to accomplish fuel injec-
tion timing. All timing and fuel adjustments are electrically made by the engine mounted Engine Control Module
(ECM).
REMOVAL
CAUTION: Cleanliness cannot be overemphasized when handling or replacingdieselfuelsystemcompo-
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. Capor cover any open part after
disassembly. Before assembly, examine each part for dirt, grease or othercontaminants and clean if nec-
essary. When installing new parts, lubricate them with clean engine oil orclean diesel fuel only.

11. Attach C3428B, or L4407A (or equivalent) gear
puller (1) 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.
12. Remove 3 injection pump mounting nuts (6) , and remove pump from engine.
INSTALLATION
CAUTION: Cleanliness cannot be overemphasized when handling or replacingdieselfuelsystemcompo-
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. Capor cover any open part after
disassembly. Before assembly, examine each part for dirt, grease or othercontaminants and clean if nec-
essary. When installing new parts, lubricate them with clean engine oil orclean diesel fuel only.

1. Inspect pump mounting surfaces at pump and
mounting flange and pilot bore for nicks, cuts or
damage. Inspect O-ring surfaces for nicks, cuts or
damage.
2. Clean injection pump mounting flange and pilot
bore at gear housing. Also clean front of injection
pump.
3. Install new rubber O-ring (square) into machined
groove at pump mounting area.
4. Apply clean engine oilto injection pump O-ring
and pilot bore only.
The machined tapers on both injection pump shaft
and injection pump gear must be absolutely dry, clean and free of any dirt oroil 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 (3) and tightenfinger
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 housing 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 nutfinger tight only.
b. Do preliminary (light) tightening of injection
pump shaft nut.
c. Tighten 3 injection pump mounting nuts to 24
Nꞏm (18 ft. lbs.).
d. Do a final tightening of pump shaft nut to 105
Nꞏm (77 ft. lbs.).

13. Connect Fuel Control Actuator (FCA) electrical
connector (3) to rear of injection pump.
14. Install intake manifold air intake tube (above injec-
tion pump). Tighten clamps.
15. Install accessory drive belt.
16. Connect both negative battery cables to both bat-
teries.
17. 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 theEngine 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
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 theECM 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 theinstrument 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-pressure fuel leaks with a sheet of cardboard. High fuel injection
pressure can cause personal injury if contact is made with the skin.
OPERATION
High-Pressure Lines
CAUTION: The high-pressure fuel lines must be held securely in the brace. The lines cannot contact each
other or other components. Do not attempt to weld high-pressure fuel linesor to repair lines that are dam-
aged. 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 samelength 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 engineperformance.
WARNING: Due to extreme fuel pressures of up to 160,000 kpa (23,206 psi), use extreme caution when
inspecting for high-pressure fuel leaks. Do not get your hand or a finger near a suspected leak. 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.
Start the engine. Move the cardboard over the suspected high-pressure fuel line leak, and check for fuel spray onto
the cardboard. If line is leaking, retorque line while engine is shutdown.Replace damaged, restricted or leaking
high-pressure fuel lines with the correct replacement line.
CAUTION: The high-pressure fuel lines must be clamped securely in place inthe brace. 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. Only use the recommended lines when replacement of high-pressure fuel line is neces-
sary.

REMOVAL
CAUTION: Cleanliness cannot be overemphasized when handling or replacingdieselfuelsystemcompo-
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. Capor cover any open part after
disassembly. Before assembly, examine each part for dirt, grease or othercontaminants and clean if nec-
essary. When installing new parts, lubricate them with clean engine oil orclean diesel fuel only.
1. Disconnect both negative battery cables from both
batteries. Cover and isolate ends of cables.
2. Thoroughly clean fuel lines at both ends.
3. If removing fuel line at either No. 1 or No. 2 cylin-
der, the intake manifold air heater elements must
first be removed from top of intake manifold. Refer
to Intake Air Heater Removal / Installation for pro-
cedures.
4. If removing fuel line at No. 6 cylinder, a bracket (1)
is located above fuel line connection at cylinder
head. Two bolts secure this bracket to rear of cyl-
inder head. The upper bolt hole is slotted. Loosen
(but do not remove) these 2 bracket bolts. Tilt
bracket down to gain access to No. 6 fuel line con-
nection.
5. Remove engine lift bracket (if necessary).
6. Remove necessary insulated fuel line support
clamps (2) at intake manifold. DO NOT remove
insulators from fuel lines.
7. Place shop towels around fuel lines at fuel rail and
injectors. If possible, do not allow fuel to drip down
side of engine.
CAUTION: When loosening or tightening high-pressure lines attached to a separate fitting , use a back-up
wrench on fitting. Do not allow fitting to rotate. Damage to both fuel line and fitting will result.