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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.
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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.
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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.
