MBE 4000 – Section 2.1 Injector Unit Pump

Section 2.1
Injector Unit Pump

A special tool is required for this procedure.‪

Section 2.1.1
Injector Unit Pump Removal

Remove the injector unit pump as follows:‪

1. Remove the engine trim cover.
2. Unscrew the fuel filter cap. See Figure "Main Fuel Filter (exploded view)" .
   

   1. Fuel Filter Cap‪	3. Filter Element‪
   2. O-ring‪

   Figure 1. Main Fuel Filter (exploded view)

   Note: Unscrewing the fuel filter cap releases pressure in the fuel system, causing fuel to flow through the return lines and back into the tank.

3. Disconnect the engine wiring harness from the injector unit pump. See Figure "Unit Pump Electrical Wires" .
   

   1. Engine Wiring Harness‪	3. Terminal Screw‪
   2. Terminal‪	4. Injector Unit Pump‪

   Figure 2. Unit Pump Electrical Wires

   PERSONAL INJURY ‪
   To avoid injury from the sudden release of a high-pressure hose connection, wear a face shield or goggles.‪

4. Remove the high-pressure fuel injector line. Refer to "2.3.1 Removal of High Pressure Fuel Line and Transfer Tube" .
5. Disconnect the fuel line at the fuel gallery inlet. Have a suitable container ready to catch any fuel that comes out of the cylinder block or fuel line.
6. Drain fuel from the engine through the fuel gallery outlet on the return lines. See Figure "Drain Fuel from the Return Lines" .
   

   1. High-Pressure Fuel Injector Line‪	4. Banjo Fitting‪
   2. Hollow-Core Banjo Bolt‪	5. Pressure Limiting Valve‪
   3. Seal Rings‪	6. Fuel Gallery Outlet‪

   Figure 3. Drain Fuel from the Return Lines

   1. Remove the outer banjo bolt and fitting from the pressure limiting valve. Discard the seal rings.
   2. Have a suitable container ready to catch any fuel that runs out of the cylinder block or return lines.
   3. Unscrew the threaded end of the pressure limiting valve from the fuel gallery outlet.
   4. Remove the inner banjo fitting from the pressure limiting valve. Discard the seal rings.
   5. Mark the fasteners with a paint pen for ease of installation.
   6. Clean out the fuel gallery outlet with compressed air.

   Note: This step is necessary to prevent fuel from contaminating the engine oil in the block.

7. Remove the end cover from the lower right side of the flywheel housing, then attach the engine barring tool (J-46392).

   EYE INJURY ‪
   To avoid injury from flying parts when working with components under spring tension, wear adequate eye protection (face shield or safety goggles).‪

8. Carefully loosen the injector unit pump mounting bolts about 6 mm (0.25 in.), but do not remove them yet. See Figure "Loosen the Mounting Bolts" .
   

   1. Mounting Bolt‪

   2. Head of Unit Pump‪

   Figure 4. Loosen the Mounting Bolts

9. Using the engine barring tool (J-46392), rotate the crankshaft until the cam pushes the unit pump upwards.

   NOTICE:
   If the injector unit pump doesn't come out easily, do not try to pry up on the body of the pump. This will damage it. ‪

10. If the injector unit pump is locked up, or frozen, in its seat, release it using the blade of a small screwdriver under the flange where the mounting bolt attaches. See arrow in Figure "Releasing a Locked-up Pump" .
    

    Figure 5. Releasing a Locked-up Pump

11. Remove both mounting bolts completely. Carefully pull the unit pump out of the cylinder block. See Figure "Removing the Unit Pump" .
    

    1. Mounting Bolt‪	3. Cylinder Block‪
    2. Unit Pump‪

    Figure 6. Removing the Unit Pump

12. Check the injector unit pump for fuel leakage at the solenoid. If leakage is found,refer to "2.1.2 Repairing the Unit Pump Solenoid" .
13. Check the injector unit pump for wear or damage. If any is found replace unit pump.Refer to "2.1.3 Injector Unit Pump Installation" .
14. Remove and discard the two O-rings on the unit pump shaft.

Section 2.1.2
Repairing the Unit Pump Solenoid

A Unit Pump Solenoid repair kit (P/N: 0120740001) is now available for repair of the unit pump. This service kit is used to repair fuel leakage at the solenoid. For this type of complaint, total replacement of the unit pump is no longer necessary. Perform the following steps to install the unit pump repair kit.‪

PERSONAL INJURY ‪
To avoid injury from penetrating fluids, do not put your hands in front of fluid under pressure. Fluids under pressure can penetrate skin and clothing.‪

FIRE ‪
To avoid injury from fire, keep all potential ignition sources away from diesel fuel, including open flames, sparks, and electrical resistance heating elements. Do not smoke when refueling.‪

1. Identify the failed unit pump and failure mode (fuel leak at the solenoid). Remove the failed unit pump. Refer to "2.1.1 Injector Unit Pump Removal" for unit pump removal procedure. See Figure "Unit Pump Components" .
   

   1. Stop Plate‪	7. Screw‪
   2. Unit Pump‪	8. Model Plate‪
   3. Anchor Plate‪	9. Cross Piece‪
   4. Seal‪	10. O-ring‪
   5. Intermediate Plate‪	11. O-ring‪
   6. Magnet‪

   Figure 7. Unit Pump Components

2. Wipe the pump clean, removing excess fuel.
3. Remove the O-rings from the unit pump. Push the unit pump O-ring installer (J-45373) onto the unit pump. This will prevent dirt from entering the unit pump holes.
4. Mark the position of the intermediate plate in relation to the unit pump body (See arrow A of Figure "Removing the Magnet and Intermediate Plate" ) and rest the unit pump on the stop plate. Use a pencil or scribe for marking. Do not use any stamping tools.
   

   1. Intermediate Plate‪	3. Special Torx Bit‪
   2. Screw‪

   Figure 8. Removing the Magnet and Intermediate Plate

5. Remove all traces of paint from screw heads. Remove screws using the special torx bit (DDC P/N: 9045890210/00) and lift off the magnet together with the intermediate plate and model plate. (See arrow B of Figure "Removing the Magnet and Intermediate Plate" ).
6. Remove the intermediate plate and the model plate from the magnet. Wipe clean the sealing surface on the magnet, removing any excess fuel. Clean the model plate and remove paint from the screw heads contact area.
7. Remove the two spacer seals and clean the intermediate plate. Do not damage sealing surfaces.
8. Mark the cross piece and anchor plate in relation to the unit pump. (See arrow C of Figure "Marking the Cross Piece and Anchor Plate" ). Use a marker; do not use a scribe or stamping tool. The cross piece should not be moved or twisted.
   

   1. Unit Pump‪	3. Cross Piece‪
   2. Anchor Plate‪

   Figure 9. Marking the Cross Piece and Anchor Plate

9. Wipe clean the sealing surfaces on the unit pump, cross piece, and anchor plate, removing any excess fuel. Clean the parts thoroughly. Do not remove the paint on the unit pump; it is used as a reference point for the intermediate plate assembly.
10. Remove the stop plate.
11. Place a new stop plate under the unit pump body.
12. Install the new seals in the intermediate plate. Protect the seals with a thin layer of high-temperature grease.
13. Place the intermediate plate on the unit pump body. Observe the identification mark on the cross piece and anchor plate for the unit pump body. The cutouts (see arrows D of Figure "Installing the Intermediate Plate" ) at the opening in the intermediate plate must face towards the cross piece. The painted surface is a reference mark to the intermediate plate assembly on the unit pump.
    

    1. Anchor Plate‪	3. Intermediate Plate‪
    2. Cross Piece‪

    Figure 10. Installing the Intermediate Plate

14. Place the magnet on the intermediate plate and place the model plate on the magnet.
15. Secure the model plate, magnet, intermediate plate, unit pump and stop plate together using new screws. Hand tighten.
16. Tighten the screws in a crosswise pattern to 5 N·m (4 lb·ft), using the special torx bit (DDC P/N: 9045890210/00). (See arrow B of Figure "Removing the Magnet and Intermediate Plate" ).
17. Push the unit pump O-ring installer (J-45373) onto the unit pump.
18. Install new O-rings on the unit pump and install the unit pump in the engine. Refer to "2.1.3 Injector Unit Pump Installation" for installation procedures.

Section 2.1.3
Injector Unit Pump Installation

Install the injector unit pump as follows:‪

1. Lubricate two new O-rings with a light coating of engine oil.
2. Install the two new O-rings on the unit pump shaft using the Unit Pump O-ring installer (J-45373). See Figure "O-ring Installation" .
   

   1. Inner (larger) O-ring‪

   2. Outer (smaller) O-ring‪

   Figure 11. O-ring Installation

3. Install the injector unit pump into the cylinder block.
   1. Insert the injector unit pump into the mounting hole in the cylinder block.
   2. Use light hand pressure to push in the unit pump until it seats, about 4 mm (0.16 in.). If it won't seat easily, rotate the crankshaft until the unit pump seats.

      Note: Use the bolt mounting holes on the engine as a guide for positioning the injector pump.

4. Install the mounting bolts, and tighten to 65 N·m (48 lb·ft).
5. Connect the engine wiring harness to the injector unit pump.
6. Remove the engine cranking tool and replace the inspection cover on the flywheel housing. Tighten the inspection cover mounting bolts to 25 N·m (18 lb·ft).

   PERSONAL INJURY ‪
   To avoid injury from the sudden release of a high-pressure hose connection, wear a face shield or goggles.‪

7. Connect the fuel line at the fuel gallery inlet. Tighten the fitting to 50 N·m (37 lb·ft).
8. Install the fuel lines and pressure limiting valve on the fuel gallery outlet. Tighten all fasteners to 50 N·m (37 lb·ft).
   1. Install the inner banjo fitting, and two new seal rings, on the pressure limiting valve, as marked on removal.
   2. Install the threaded end of the pressure limiting valve in the fuel gallery outlet. When the valve is firmly seated, tighten to 50 N·m (37 lb·ft).
   3. Install the outer banjo fitting, again with two new seal rings, on the banjo bolt, as marked on removal.
   4. Install the banjo bolt on the pressure limiting valve and tighten to 40-50 N·m (30-37 lb·ft).
9. Install the fuel filter cap. Inspect the O-ring in the fuel filter and replace it if worn. Tighten the cap nut to 25 N·m (18 lb·ft).
10. Install the high-pressure fuel injector line. Refer to "2.3.2 Installation of High Pressure Fuel Injector Lines" .

    PERSONAL INJURY ‪
    Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.‪ Always start and operate an engine in a well ventilated area. If operating an engine in an enclosed area, vent the exhaust to the outside. Do not modify or tamper with the exhaust system or emission control system.

11. Prime the fuel system.
12. Start the engine and check for leaks. Tighten connections as needed.
13. Install the engine trim cover.