Fuel Pump Module

This procedure removes and replaces the fuel pump module in the fuel tank of a 1994-2007 Dodge Ram 2500 with the 5.9L Cummins diesel engine.

Warnings

Tools required

Parts

• Fuel pump module assembly × 1 — Use OEM specification
• Fuel pump lock ring O-ring/seal × 1 — Included with most pump modules or order separately
• Fuel line O-rings × 2 — Viton fuel-rated O-rings

Preparation

1. Park vehicle on level ground with adequate ventilation. Ensure the work area is free of ignition sources.
2. Disconnect both negative battery cables to eliminate all electrical sources near fuel system.
3. Verify fuel level is below 1/4 tank. If above 1/4 tank, drain fuel through tank drain plug or siphon fuel safely into approved containers before proceeding.
4. Chock front wheels securely.
5. Position fire extinguisher within immediate reach of work area.

Procedure

1. 1

   Relieve fuel system pressure
   Allow the engine to sit for at least 2 hours after last operation to allow fuel pressure to bleed down naturally. On Cummins diesel systems, residual pressure remains in the system. Place shop towels around any connection point before loosening to catch fuel spray.
   ⚠️Fuel will spray when lines are loosened. Wrap connections with towels and release slowly.
2. 2

   Access fuel tank
   Raise rear of vehicle using floor jack and support securely on jack stands rated for vehicle weight. For 4WD models, ensure adequate clearance to access top of fuel tank. Remove spare tire if mounted under bed and interfering with access.
   ⚠️Never work under a vehicle supported only by a jack. Use proper jack stands.
3. 3

   Remove bed access cover or fuel tank shield
   The 1994-2007 Ram 2500 does not have a bed access panel over the fuel pump module. The fuel tank must be lowered to access the pump. Support the tank with a transmission jack or floor jack with a wide platform, then remove the two tank strap bolts and carefully lower the tank enough to reach the top-mounted pump module, fuel lines, and electrical connector.
   Torque spec

   Access Cover Screws4 Nm (3 lb-ft)
4. 4

   Clean fuel tank area
   Thoroughly clean the entire area around the fuel pump module lock ring and fuel line connections using a clean rag. Remove all dirt, debris, and loose material. This step is critical to prevent contamination of the fuel system. Blow out area with compressed air if available, directing debris away from the opening.
   ⚠Any debris falling into the fuel tank can damage the high-pressure injection pump. Take extra time to ensure absolute cleanliness.
5. 5

   Disconnect fuel lines and electrical connector
   Disconnect the electrical connector from the fuel pump module by pressing the release tab. Using appropriate fuel line disconnect tools, disconnect the supply and return fuel lines from the top of the pump module. Expect residual fuel spillage; catch with shop towels. Cap or plug open lines immediately to prevent contamination.
   ⚠Diesel fuel will drain from lines. Have absorbent materials ready and dispose of properly.
   Torque spec

   Fuel Line Fittings25 Nm (18 lb-ft)
6. 6

   Remove fuel pump lock ring
   Using the appropriate fuel pump lock ring tool (verify correct Mopar/OEM tool number for your specific tank), rotate the lock ring counterclockwise to loosen. The lock ring may be tight; tap the tool with a brass punch if needed, but avoid sparking. Once loosened, remove lock ring completely and set aside with its seal.
   ⚠Do not use steel punches or hammers that can create sparks near fuel vapors. Use brass or non-sparking tools only.
   Torque spec

   Fuel Pump Lock Ring68 Nm (50 lb-ft)
7. 7

   Remove fuel pump module
   Carefully lift the fuel pump module assembly straight up and out of the fuel tank. The module has a float arm and pump assembly that extends downward; angle it carefully to avoid damaging components or the fuel level sender. Expect fuel to drain from the module reservoir. Place module in a fuel-safe drain pan.
   ⚠The fuel level sender arm is fragile. Avoid bending or damaging during removal.
8. 8

   Inspect fuel tank opening and seal surface
   With the module removed, inspect the fuel tank opening for debris, corrosion, or damage. Check the seal surface on the tank where the O-ring mates; it must be clean and smooth. Remove the old O-ring seal from the lock ring or tank and discard. Do not allow any debris to fall into the tank.
   ⚠This is your only opportunity to inspect the inside of the tank. Look for contamination, rust, or water accumulation that could indicate fuel quality issues.
9. 9

   Install new fuel pump module
   Install new O-ring seal onto the new fuel pump module or into the lock ring groove (depending on design). Ensure O-ring is properly seated and not twisted. Carefully lower the new pump module into the fuel tank, ensuring the orientation aligns with the tank mounting (alignment tab or notch present on most models). The float arm should move freely and not contact tank walls.
   ⚠Verify correct module orientation before installing lock ring. Incorrect orientation will prevent lock ring installation and may damage the fuel level sender.
10. 10

    Install and torque lock ring
    Position the lock ring over the fuel pump module and rotate clockwise by hand until it engages the tank threads. Using the fuel pump lock ring tool and torque wrench, tighten the lock ring to specification. Ensure the module remains properly oriented during tightening and that the O-ring seal is not pinched or displaced.
    Torque spec

    Fuel Pump Lock Ring68 Nm (50 lb-ft)
11. 11

    Reconnect fuel lines
    Install new O-rings on fuel line fittings. Lubricate O-rings lightly with clean diesel fuel or petroleum jelly. Connect supply and return fuel lines to the pump module, ensuring they click or seat fully. If lines use threaded fittings, torque to specification using a flare nut wrench to avoid rounding fittings.
    ⚠Always use new O-rings on fuel line connections. Reusing old O-rings can cause leaks and potential fire hazard.
    Torque spec

    Fuel Line Fittings25 Nm (18 lb-ft)
12. 12

    Reconnect electrical connector
    Connect the electrical connector to the fuel pump module, ensuring it clicks fully into place and the locking tab engages. Verify the connector seal is in good condition to prevent moisture intrusion.
13. 13

    Reinstall access cover
    Raise the fuel tank back into position with the transmission/floor jack, aligning it correctly. Reinstall the tank straps and torque the strap bolts to specification. Verify fuel lines and wiring are not pinched between the tank and frame.
    Torque spec

    Access Cover Screws4 Nm (3 lb-ft)
14. 14

    Reconnect battery and prime fuel system
    Reconnect negative battery cables. Prime the fuel system per your model year's procedure. On 2003-2007 common-rail trucks, cycle the ignition ON (without cranking) several times, allowing the lift pump to run each cycle. On 1994-2002 mechanically-injected trucks, priming may require extended key-on cycles or manual priming; consult the service manual for your specific engine. Check all connections at the pump module for leaks.
    ⚠️Immediately stop if any fuel leaks are detected. Disconnect battery and repair leak before proceeding.

Reassembly

1. Lower vehicle from jack stands after verifying no leaks are present at fuel tank connections.
2. Reinstall spare tire if removed during access.
3. Reinstall bed liner or mat if removed.
4. Dispose of old fuel pump module and contaminated rags according to local environmental regulations.

Verification

• Start the engine and verify it runs smoothly without extended cranking (should start within 10-15 seconds).
• Allow engine to idle for 5 minutes while monitoring for fuel leaks at all connections at the pump module.
• Check that fuel gauge reads correctly and corresponds to actual fuel level.
• Verify no fuel odor is present in cab or near fuel tank area.
• Test drive vehicle and verify normal fuel delivery under load with no hesitation or fuel starvation symptoms.
• Re-check all fuel line connections for leaks after test drive.

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