Cummins ISX11.9 CM2250 – Service Manual 005-227   Fuel Pump Head

Use the following procedure for instructions to measure the fuel pump head drain. Refer to Procedure 005-236 in Section 5.

WARNING  When using a steam cleaner, wear safety glasses or a face shield, as well as protective clothing. Hot steam can cause serious personal injury.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

CAUTION  Clean all fittings before disassembly. Dirt or contaminants can damage the fuel system.

Before servicing any fuel system components, (such as fuel lines, fuel pump, injectors, etc.) which would expose the fuel system or internal engine component to potential contaminants prior to disassembly, clean the fittings, mounting hardware, and the area around the component to be removed. Dirt or contaminants can be introduced into the fuel system and engine if the surrounding areas are not cleaned, resulting in damage to the fuel system and engine.

Clean the fuel pump head and surrounding area with contact cleaner, Part Number 3824510 or equivalent.

To prevent damage from debris and contamination, cover, cap, or plug any openings as soon as possible when servicing the fuel system.  Caps and plugs can be found in Clean Care Kit, Part Number 4919073.

WARNING  Normal engine operation creates highly pressurized fuel in the fuel line which will remain in the fuel line after engine shutdown. Never open the fuel system when the engine is operating. Before servicing the fuel system, always loosen the pump to rail fuel line at the rail to vent the pressure. Keep hands clear of the line when loosening. High pressure fuel spray can penetrate the skin, resulting in serious personal injury or death.

Before servicing the fuel system, loosen the pump to rail line at the rail to vent the pressure.

Keep hands clear of the line when loosening.

NOTE: A machined slot in this fitting directs the fuel spray toward the inboard side of the fuel rail.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Disconnect the batteries. Refer to the OEM service manual.
• Disconnect the fuel drain line from the fuel pump head. Refer to Procedure 006-013 in Section 6.
• Remove the fuel supply line from the fuel pump head. Refer to Procedure 006-024 in Section 6.
• Disconnect the wiring harness from the fuel pump actuator.

CAUTION  Do not use an air tool. The use of air tools can possibly damage the fuel pump.

Remove two of the four capscrews that are located diagonally from one another.

Remove the last two capscrews. Alternately loosen each capscrew to avoid binding. Loosen each capscrew about one turn at a time.

Carefully lift the fuel pump head from the fuel pump camshaft housing, being careful to keep the tappet springs attached to the pump head. Place the head on a clean surface.

Check the pumping plungers to make sure that they move freely.

Blow clean compressed air into the fuel inlet of the fuel pump head. The plungers will extend to the tappet spring retainers. If the pumping plungers do not extend to the tappet spring retainers, replace the fuel pump head.

Check for broken or cracked plungers.

Push the pumping plungers into the plunger bore.

Release the plungers.

The plungers must resist being pushed into the bore, and spring back when they are released. If the plungers do not spring back when they are released, replace the fuel pump head.

If a plunger is removed from the fuel pump head, the plunger must be installed in the same location.

The plunger is asymmetrical. The flat end of the plunger will be toward the fuel pump camshaft when installed correctly.

CAUTION  Each plunger must be installed in the same orientation and in the same barrel, or engine damage can result. Marking the bottoms of the plungers with a felt tip marker will help to ensure that correct orientation is maintained.

If the plungers are removed, inspect the plungers. Slight discoloration or debris traces is acceptable. Deep scoring must not be evident.

If scoring or scratches exist that can be felt, the fuel pump head must be replaced.

While the fuel pump head is removed, inspect the cam housing.

The tappets can be removed. Use an o-ring pick as the removal tool.

Normal operation creates vertical grooves in the cylinder bores of the fuel pump camshaft housing. These grooves are not an indication of a malfunction.

Camshaft housings with grooves are acceptable for reuse.

Normal operation creates stippled lines on the circumference of the camshaft lobes. These lines are not an indication of a malfunction.

If excessive pitting is present on the nose or the lobes of the camshaft, the fuel pump must be replaced.

Refer to Bulletin 3666052, Camshaft Reuse Guidelines for Cummins® Engines with Roller Followers or Roller Tappets, for additional camshaft inspection criteria.

Inspect the tappet guide pins and tappet guide pin grooves for excessive wear.

If more than 25 percent guide pin or groove wear is observed, the fuel pump must be replaced.

Inspect the tappet rollers for wear.

If excessive pitting on the rollers is observed, the fuel pump must be replaced.

Normal operation creates grooves around the circumference of the tappet roller. These grooves are not an indicator of a malfunction. Tappet rollers with grooves are acceptable for reuse.

If damage to the camshaft, tappets, or cam housing is observed, it is possible the fuel pump is not receiving adequate lubricating oil.

When replacing the fuel pump, inspect the gear housing to make sure no blockages exist in the oil supply to the fuel pump.

Install the tappets in the original tappet bores.

Be certain the tappets are installed in the original locations.

Be certain that the tappet guide pins engage the guide pin grooves.

Tappet guide pins must be aligned so that the guide pin flats are perpendicular to the fuel pump head mounting surface.

Rotate the guide pin to the appropriate position if the guide pin is misaligned.

If installing a new or rebuilt pump head, install the new tappet springs and retainers provided with the pump head.

Place the high-pressure fuel pump head onto the high-pressure fuel pump cam housing.

Draw the high-pressure fuel pump head down by alternately tightening the four high-pressure fuel pump head capscrews until the head just contacts the cam housing.

Tighten the four high-pressure pump fuel head capscrews to the final torque.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Connect the fuel supply line to the fuel pump head. Refer to Procedure 006-024 in Section 6.
• Connect the fuel drain line to the fuel pump head. Refer to Procedure 006-013 in Section 6.
• Connect the wiring harness to the fuel pump actuator. Refer to Procedure 019-117 in Section 19.
• Connect the batteries. Refer to the OEM service manual.
• Operate the engine and check for leaks.