Fuel injectors DODGE RAM SRT-10 2006 Service Owners Manual

PUMP - FUEL TRANSFER
DESCRIPTION
The fuel transfer pump (fuel lift pump) is part of the fuel pump module. The fuel pump module is located in the fuel
tank. The 12–volt electric pump is operated and controlled by the Engine Control Module (ECM). The ECM controls
a relay in the Intelligent Power Module(IPM) for transfer pump operation.
OPERATION
The purpose of the fuel transfer pump is to supply (transfer) a low-pressure fuel source:fromthe fuel tank,through
the fuel filter/water separator andtothe fuel injection pump. Here, the low-pressure is raised to a high-pressure by
the fuel injection pump for operation of the high-pressure fuel injectors. Check valves within the pump, control direc-
tion of fuel flow and prevent fuel bleed-back during engine shut down.
Maximum current flow to the pump is 5 amperes.
With the engine running, the pump has a 100 percent duty-cycle.
The transfer pump is self-priming: When the key is first turned on (withoutcranking engine), the pump will operate
for approximately 2 seconds and then shut off (Note: When ambient temperatures are cold enough to cause the
intake air heaters to operate, the fuel lift pump will operate during the entire intake air pre-heat cycle). The pump will
also operate for up to 25 seconds after the starter is engaged, and then disengaged and the engine is not running.
The pump shuts off immediately if the key is on and the engine stops running.
The fuel volume of the transfer pump will always provide more fuel than the fuel injection pump requires. Excess
fuel is returned from the injection pump through an overflow valve, and then back to the fuel tank.
REMOVAL
The fuel transfer pump (fuel lift pump) is a part of the fuel tank module. It is not serviced separately. Refer to Fuel
Tank Module Removal or Installation for procedures (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/FUEL TANK
MODULE - REMOVAL).
INSTALLATION
The fuel transfer pump (fuel lift pump) is a part of the fuel tank module. It is not serviced separately (Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY/FUEL TANK MODULE - INSTALLATION).

CIRCUIT - FUEL DRAIN
OPERATION
The Fuel Drain Circuit incorporates several sources of fuel return. Fuel travels from the fuel tank (via the fuel trans-
fer pump) and is forced through the fuel filter. This fuel then travels intothe fuel injection pump. It then goes to a
fuel drain line and returns back to the fuel tank.
The fuel that flows to the fuel pump is pressurized by a gear pump and internally transferred to the fuel injection
pump. At this point the fuel is channeled into two passages. One passage sends fuel to the FCA (Fuel Control
Actuator). The other passage sends fuel to the cascade overflow valve. Theoverflow valve sends some fuel to a
lubrication passage. The rest of the fuel is sent to a drain passage which connects to an external fuel line.
Fuel that travels through the FCA is pressurized by the fuel injection pumpand sent through an external high pres-
sure fuel line to the fuel rail. At the fuel rail, fuel is sent to the fuel injectors. If fuel pressure in the fuel rail becomes
excessive, the pressure limiting valve opens and sends fuel through an external fuel line.
At the fuel injector, fuel that is not injected is used for lubrication of the fuel injectors. This fuel then travels through
an internal passage that is connected to the rear of the cylinder head, an then into an external fuel line. This line is
connected to the vehicles fuel return line, and returns excess fuel back and into the fuel tank.

INJECTOR - FUEL
DESCRIPTION
Six individual, solenoid actuated high-pressure fuel
injectors are used. The injectors are vertically mounted
into a bored hole in the top of the cylinder head. This
bored hole is located between the intake/exhaust
valves.
High-pressure connectors, mounted into the side of the cylinder head, connect each fuel injector to each high-pres-
sure fuel line. The injector part number is laser-burned onto the injector. Failure to replace with the proper injector
will cause severe engine damage.

OPERATION
High-pressure fuel is supplied from the injection pump, through a high-pressure fuel line, into a fuel rail, through
high-pressure lines, through steel connectors and into the solenoid actuated fuel injector. The ECM actuates the
solenoid causing the needle valve to rise and fuel flows through the spray holes in the nozzle tip into the combus-
tion chamber.
Each fuel injector is connected to the fuel rail by a high-pressure fuel line and a steel connector. This steel con-
nector is positioned into the cylinder head and sealed with an O-ring. The connector is retained in the cylinder head
by a nut (fitting) that is threaded into the cylinder head.
The torquing force of this threaded nut (fitting) provides a sealing pressure between the fuel line connector and the
fuel injector.Retaining nut torque is very critical.If the nut (fitting) is under torqued, the mating surfaces will not
seal and a high-pressure fuel leak will result. If the fitting is over torqued, the connector and injector will deform and
also cause a high-pressure fuel leak. This leak will be inside the cylinderhead and will not be visible. The result will
be a possible fuel injector miss-fire and low power, or a no-start condition.
The fuel injectors use hole type nozzles. High-pressure flows into the side of the injector, the ECM activates the
solenoid causing the injector needle to lift and fuel to be injected. The clearances in the nozzle bore are extremely
small and any dirt or contaminants will cause the injector to stick. Because of this, it is very important to do a
thorough cleaning of any lines before opening up any fuel system component. Always cover or cap any open fuel
connections before a fuel system repair is performed.
Each fuel injector connector tube contains an edge filter that is designedto break up small contaminants before
entering the fuel injector.The edge filters are not a substitute for proper cleaning and covering of allfuel
system components during repair.
The bottom of each fuel injector is sealed to the cylinder head with a1.5mmthick copper shim (gasket). The correct
thickness shim must always be re-installed after removing an injector.
Fuel pressure in the injector circuit decreases after injection. The injector needle valve is immediately closed and
fuel flow into the combustion chamber is stopped. Exhaust gases are prevented from entering the injector nozzle by
the needle valve.
REMOVAL
CAUTION: Refer to Cleaning Fuel System Parts.
Six individual, solenoid actuated high-pressure fuel
injectors (7) are used. The injectors are vertically
mounted into a bored hole in the top of the cylinder
head. This bored hole is located between the intake/
exhaust valves. High-pressure connectors, mounted
into the side of the cylinder head, connect each fuel
injector to each high-pressure fuel line.
1. Disconnect both negative battery cables from both batteries. Cover andisolate ends of cables.
2. Remove vanity cover.
3. Remove breather assembly and tubes.

4. Remove valve cover (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - REMOVAL).
5. Remove all 12 fuel injector wire harness nuts (1) securing integrated wiring harness to all 6 fuel injectors.
6. Remove all 12 fuel injector wire harness nuts (1)
securing integrated wiring harness to all 6 fuel
injectors.
7. An integrated fuel injector wire harness / valve
cover gasket (2) is used. After all 12 nuts (1) have
been removed, remove this integrated gasket.
Before removing gasket, disconnect engine wiring
harness at both electrical connectors (3).
8. Remove necessary high pressure fuel line connecting the necessary fuelinjector rail to high pressure connector.
Refer to Fuel Line Removal for procedures.
9. A connector retainer (nut) is used on each connector tube. Remove this nut(s) by unthreading from cylinder
head.

3. The bottom of fuel injector is sealed to cylinder
head bore with a copper sealing washer (shim) (1)
of a certain thickness. A new shim (1) with correct
thickness must always be re-installed after remov-
ing injector. Measure thickness of injector shim (1).
Shim Thickness: 1.5 mm (.060”)
4. Install new shim (1) (washer) to bottom of injector.
Apply light coating of clean engine oil to washer.
This will keep washer in place during installation.
5. Install new o-ring to fuel injector. Apply small
amount of clean engine oil to O-ring and injector
bore.
6. Install injector into cylinder head with male (high-
pressure) connector port facing the intake manifold.
Push down on fuel injector mounting flange to
engage O-ring and seat injector.
7. Tightening Sequence:
a. Install fuel injector holdown clamp (mounting
flange) bolts. Be sure the clamp is perpendicular to the injector body.Do a preliminary tightening of these
bolts to 5 Nꞏm (44 in. lbs.) torque. This preliminary tightening insures the fuel injector is seated and
centered.
b. After tightening, relieve bolt torque, but leave both bolts threaded inplace.
c. Install high-pressure connector and retaining nut. Do a preliminary tightening to 15 Nꞏm (11 ft. lbs.) torque.
d. Alternately tighten injector holdown bolts to 10 Nꞏm (89 in. lbs.) torque.
e. Do a final tightening of the high-pressure connector and retaining nut.Tighten to 50 Nꞏm (37 ft. lbs.) torque.
8. Install integrated gasket
9. Connect injector solenoid wires and nuts to top of injectors. Tighten connector nuts to 1.25 Nꞏm (11 in. lbs.)
torque.Be very careful not to overtighten these nuts as damage to fuel injector willoccur.
10. Install exhaust rocker arm assembly. Refer to the Diesel Engine section.
11. Set exhaust valve lash. Refer to the Diesel Engine section.
12. Install fuel connector tube nut at cylinder head and tighten to 50 Nꞏm (37ft.lbs.).Be sure to use a secondary
back-up wrench on the connector nut (fitting) while torquing fuel line fitting.Refer to Fuel Line Installation
for additional information.
13. Install valve cover (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - INSTALLATION).
14. Install breather assembly.
15. Connect negative battery cables to both batteries.

FUEL INJECTOR RAIL
DESCRIPTION
The fuel injector rail is bolted to the top of the intake manifold.
OPERATION
The fuel rail is used as a distribution device to supply high-pressure fuelto the high-pressure fuel lines.
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 at both
batteries. Isolate ends of both cables.
2. Disconnect electrical connector at fuel pressure
sensor.
3. Remove banjo bolt at fuel limiting valve.
4. Disconnect necessary wiring harness retention
clips from intake manifold.
5. Lift 2 rubber covers to gain access to positive (+),
intake heater cable nuts. Remove 2 nuts and
remove 2 cables from studs.
6. Carefully remove 4 high-pressure fuel lines from
top of fuel rail. Note position of each line while
removing.Do not bend lines while removing.
CAUTION: WHEN LOOSENING OR TIGHTENING
HIGH-PRESSURE LINES ATTACHED TO A SEPA-
RATE FITTING, USE A BACK-UP WRENCH ON FIT-
TING. DO NOT ALLOW FITTING TO ROTATE.
DAMAGE TO BOTH FUEL LINE AND FITTING WILL
RESULT.
7. Carefully remove 2 high-pressure fuel lines at each end of fuel rail. Note position of each line while removing.Do
not bend lines while removing.(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/FUEL LINES - REMOVAL).
8. Remove fuel line connectinginjection pump to fuel rail.
9. Remove three injection rail mounting bolts.
10. Remove rail from top of intake manifold.