ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – 006-024   Fuel Supply Lines

Inspect all fuel supply lines and fittings. Look for cracks in the lines or leaking fittings.

Inspect the straight thread o-ring metric hose fitting. Make sure the lock nuts tighten against the o-ring rather than bottom out against the end of the fitting’s threads (example: Cummins® Accumulator Pump System fuel pump inlet and Cummins® Accumulator Pump System fuel filter head).

Inspect the quick-disconnect style fittings for damaged o-ring connections or broken locking tangs.

Inspect the banjo style fittings for leaks at the sealing washers.

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 Procedure 013-009 in Section 13.
• Close the fuel supply and return valves. Refer to the OEM service manual.
• Clean all fittings before disassembly. Dirt or contaminants can damage the fuel system.

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

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.

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 can 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. Refer to Procedure 000-009 in Section 0.

WARNING  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.

Remove the fuel supply lines.

For quick disconnect style fuel lines, remove the clasp from the fuel line brace. This will allow the lines to move so they can be disconnected.

Loosen all quick disconnect lines from the brace.

To remove the gear pump outlet line, the gear pump inlet line must be removed first.

Remove the quick disconnect style fuel lines by pressing in the locking tangs on both sides of the quick disconnect fitting.

To aid in the removal of quick disconnect style fuel lines, slide removal tool, Part Number 4918878, over the locking tangs. Make sure the tool is removed from the fuel line as soon as possible after line has been disconnected. Inadvertently leaving the tool in place can result in fuel leaks.

To aid removal, a screwdriver may be inserted between the fuel line end and quick disconnect male union. After pressing the opposing locking tangs, twisting the flat blade of the screwdriver helps to remove the fuel line.

If fuel leaks or suction side air entry is suspected, remove the fuel hoses or quick disconnect fittings.

WARNING  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.

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 OEM fuel supply line.

Disconnect the fuel line from the fuel line mounting bracket and the upper electronic control module (ECM) cooler fuel connection.

Disconnect the fuel supply line from the lower ECM cooler connection and the upper gear pump connection.

Disconnect the fuel supply line from the lower gear pump connection and the inlet to the fuel filter head.

Disconnect the fuel supply line from the fuel filter head outlet connection and the high-pressure pump connection.

Inspect for burrs or debris on metal connectors that may cause leaks.

On straight thread o-ring metric connectors, be certain the o-rings are not frayed or cut.

On quick disconnect style fittings, be certain the o-rings are not frayed or cut, and the lock tangs are not damaged.

Inspect the face of the banjo connector for sealing surface damage.

Replace the banjo bolts, sealing washers or fuel lines as necessary.

Inspect the straight thread fittings and fuel lines for cracks, bends, or any other damage.

Replace the fuel lines as necessary.

Install the fuel supply lines.

Install the quick disconnect fuel lines (Cummins® Common Rail Fuel Systems only).

Install the quick disconnect fittings.

Make sure the quick disconnect style fuel lines clasp onto the quick disconnect fittings.

Make sure the lines are routed and connected correctly. If the lines are connected incorrectly, the engine will not run.

For quick disconnect style lines used with the Cummins® Common Rail Fuel System, fuel lines are routed in the following order:

1. OEM connection to the upper fitting at the ECM cooling plate
2. Lower ECM cooling plate fitting to the upper gear pump fitting
3. Lower gear pump fitting to the 2-micron fuel filter inlet
4. 2-micron fuel filter outlet to the fuel pump fuel control actuator housing.

The fuel supply line brace holds the fuel lines in the following order:

1. The inside line connects the upper gear pump fitting to the lower ECM cooling plate fitting
2. The middle line connects the 2-micron filter outlet to the fuel pump fuel control actuator housing
3. The outside line connects the lower gear pump fitting to the 2-micron filter inlet.

Install the fuel line brace clasp (quick disconnect style fuel lines only) and the brace, if necessary.

Connect the fuel supply hose to the fuel pump and the outlet of the fuel filter. Use new sealing washers as needed

Connect the supply hose from the inlet side of the fuel filter and the lower gear pump connection. Use new sealing washers as needed.

Tighten the filter connection.

Tighten the gear pump connection.

Connect the supply line to the upper gear pump connection and the lower ECM cooler connection. Use new sealing washers as needed.

Tighten the connection.

Connect the fuel supply line to the upper ECM cooling plate connection.

Install the fuel supply line on the fuel line connector bracket.

Connect the OEM fuel supply hose. Refer to the OEM service manual.

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 arching, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Open the fuel supply and return valves, if equipped.
• Connect the batteries. Refer to Procedure 013-009 in Section 13.
• Prime the fuel system. Refer to Procedure 006-015 in Section 6.
• Operate the engine and check for leaks.