Cummins ISX11.9 CM2250 – Service Manual 005-025   Fuel Pump Gear Pump

The gear pump shaft incorporates a double seal. The first one seals oil in the fuel pump cam housing; the second one seals fuel in the gear pump. If either seal malfunctions, fluid will drip from the weep hole.

The weep hole is located near the gear pump mounting flange on the inboard side (toward the engine block).

A pilot diameter o-ring seals oil at the gear pump to cam housing interface.

Use the following procedure for details on measuring the fuel pump gear pump output pressure. 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 gear pump and surrounding area with contact cleaner, Part Number 3824510 or equivalent.

To prevent engine damage from debris or 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  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.

WARNING  Depending on the circumstance, diesel fuel is flammable. Keep all cigarettes, flames, pilot lights, arcing equipment, and switches out of the work area and areas sharing ventilation to reduce the possibility of severe personal injury or death when working on the fuel system.

WARNING  Do not vent the fuel system on a hot engine; this can cause fuel to spill onto a hot exhaust manifold, which can cause a fire.

CAUTION  Use caution when disconnecting or removing fuel lines, replacing filters and priming the fuel system that fuel is not spilled or drained into the bilge area. Do not drop or throw filter elements into the bilge area. The fuel and fuel filters must be discarded in accordance with local environmental regulations.

• Disconnect the batteries. Refer to the OEM service manual.
• Clean the fuel, oil, and any debris from the gear pump.
• Remove the fuel supply lines from the gear pump. Refer to Procedure 006-024 in Section 6.

Remove the three capscrews that hold the gear pump to the fuel pump.

Remove the gear pump from the fuel pump.

Remove the fuel pump gear pump o-ring.

Install the o-ring onto the fuel pump gear pump.

Insert the mounting capscrews through the fuel pump gear pump flange.

Index the fuel pump gear pump input shaft to engage the drive coupling and install the fuel pump gear pump.

Install the three gear pump capscrews and tighten.

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.

• Install the fuel supply lines. Refer to Procedure 006-024 in Section 6.
• Connect the batteries. Refer to the OEM service manual.
• Operate the engine to normal operating temperature and check for leaks.