DODGE RAM SRT-10 2006 Service Repair Manual

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.

8. Carefully remove each fuel line from engine. Note position of each whileremoving.Do not bend lines while
removing.
INSTALLATION
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.
CAUTION: Anytime a high-pressure line is
removed from the engine, its fuel connector nut at
the cylinder head must first be retorqued. Refer to
Torque Specifications.
1. Tighten nuts at high pressure injector connector nut
at the cylinder head. Torque nut to 50 Nꞏm (37 ft.
lbs.).
2. Position and install fuel line support clamp (2) bolts
or nut. Tighten finger tight.
3. Position proper fuel line to proper injector on
engine. Tighten fittings hand tight at both ends of
line.
4. Tighten fuel line at cylinder head. Torque nut to 30
Nꞏm (22 ft. lbs.).

5. Install engine lifting bracket (1) and bolt. Torque nut
to 77 Nꞏm (56 ft. lbs.).
6. Tighten fuel lines at fuel rail. Torque nut to 37 Nꞏm
(27 ft. lbs.).
7. Tighten clamp support to intake manifold cover.
Torque nut to 24 Nꞏm (18 ft. lbs.).
8. If fuel line at either No. 1 or No. 2 cylinder has
been replaced, install intake manifold air heater
elements to top of intake manifold. Refer to Intake
Air Heater Removal / Installation for procedures.
9. If fuel line at No. 6 cylinder has been replaced, tilt
metal bracket (shield) upward and tighten 2 bolts at
rear of cylinder head. Torque nut to 43Nꞏm (32 ft.
lbs.).
10. Connect both negative battery cables to both bat-
teries.
11. Prime fuel system. Refer to Fuel System Priming.
12. Check lines/fittings for leaks.

SENSOR - FUEL PRESSURE
DESCRIPTION
The fuel pressure sensor is mounted vertically near the top/center of the fuel rail.
OPERATION
The fuel pressure sensor monitors actual high-pressure within the fuel rail. An output signal from this sensor (relat-
ing to fuel pressure) is sent to the Engine Control Module (ECM).
REMOVAL
The fuel pressure sensor (4) is mounted vertically
near the top/center of the fuel rail.
1. Disconnect electrical connector (1) at sensor.
2. Remove sensor from fuel rail.
3. Inspect sensor sealing surface.
INSTALLATION
1. Inspect fuel pressure sensor sealing surface.
2. Lubricate sensor threads with clean diesel fuel.
3. Install sensor (4) into fuel rail.
4. To prevent leaks, sensormustbe tightened to 70
Nꞏm (52 ft. lbs.).
5. Connect electrical connector to sensor.
6. Start engine and check for fuel leaks.

VALVE - FUEL PRESSURE LIMITING
DESCRIPTION
The fuel pressure limiting valve is located on the top of the fuel rail.
OPERATION
Fuel pressure at the fuel rail is monitored by the fuel rail pressure sensor. If fuel pressure becomes excessive, the
pressure limiting valve opens and vents excess pressure into the fuel draincircuit.
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.
The fuel pressure limiting valve (3) is located on the
top of the fuel rail.
1. Thoroughly clean area at pressure limiting valve.
2. Remove banjo bolt (2) at banjo fitting.
3. Remove pressure limiting valve from fuel rail.

INSTALLATION
1. Be sure both top of manifold and limiting valve are
clean.
2. Install valve. To prevent leaks, valve must be tight-
ened to prescribed torque. Refer to Torque Specifi-
cations.
3. Assemble banjo bolt and new sealing washers to
limiting valve, copper seal against limiting valve
and rubber seal against banjo bolt (2).
4. Tighten banjo bolt. Torque to 24 Nꞏm (18 ft. lbs.).

TA N K - F U E L
DESCRIPTION
The fuel tank is similar to the tank used with gasoline powered models. The tank is equipped with a separate fuel
return line and a different fuel tank module for diesel powered models. Theelectric fuel transfer pump (lift pump) is
attached to the fuel pump module. Refer to Fuel Tank Module for additional information.
REMOVAL
1. Drain fuel tank. (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY - STANDARD PROCEDURE).
2. Support tank with a hydraulic jack.
3. Remove two fuel tank strap nuts (5) and remove both tank support straps.
4. Carefully lower tank a few inches and disconnect fuel pump module electrical connector at top of tank. To dis-
connect electrical connector: Push upward on red colored tab to unlock. Push on black colored tab while remov-
ing connector.
5. Disconnect fuel supply and return lines at fuel tank module. Refer to Quick-Connect Fittings for procedures.
6. Continue to lower tank for removal.
7. If fuel tank is to be replaced, remove fuel tank module from tank. (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY/FUEL TANK MODULE - REMOVAL).

INSTALLATION
1. If fuel tank is to be replaced, install fuel tank mod-
ule into tank. (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/FUEL TANK MODULE - REMOVAL).
2. Position fuel tank (1) to hydraulic jack.
3. Raise tank until positioned near body.
4. Connect fuel tank module electrical connector at
top of tank.
5. Connect fuel supply and return lines to tank mod-
ule.
6. Continue raising tank until positioned snug to body.
7. Install and position both tank support straps (4).
Install 2 fuel tank strap nuts and tighten to 41 Nꞏm
(30 ft. lbs.).Tighten rear strap nut first.
8. Remove hydraulic jack.
9. Connect rubber fill hose to fuel fill tube and tighten
clamp.
10. Install tire / wheel (if necessary).
11. Lower vehicle.
12. Fill fuel tank with fuel.
13. Start engine and check for fuel leaks near top of module.