Fuel Pump Module

Remove and replace the fuel pump module assembly from the saddle-style fuel tank on a 2005 Dodge Viper, requiring tank lowering and fuel system depressurization.

Warnings

Tools required

Parts

• Fuel pump module assembly × 1 — Use OEM specification (Mopar)
• Fuel pump lock ring O-ring seal × 1 — Use OEM specification
• Fuel line O-rings (supply and return) × 2 — Use OEM specification

Preparation

1. Park vehicle on level, stable ground in a well-ventilated area away from ignition sources.
2. Place Class B fire extinguisher within arm's reach of work area.
3. Ensure fuel tank is no more than 1/4 full. If more than 1/4 full, drain excess fuel using approved pump and containers before beginning work.
4. Disconnect negative battery cable and isolate it away from battery post to prevent accidental reconnection.
5. Allow engine to cool completely if recently operated (minimum 2 hours).
6. Chock front wheels securely.
7. Raise rear of vehicle using floor jack and support on jack stands at proper rear lift points (consult owner's manual for frame contact points). Vehicle must be level and stable.
8. Ground yourself to discharge static electricity before handling fuel system components.

Procedure

1. 1

   Depressurize fuel system
   With battery already disconnected, fuel pressure will bleed down passively. To accelerate depressurization, locate the fuel pump relay in the power distribution center (under hood, driver side). Remove the fuel pump relay. Reconnect battery temporarily, attempt to start engine (it will not start or may run briefly), then turn ignition off. Disconnect battery negative cable again. This purges residual pressure from fuel rails and lines. Wait 5 minutes for pressure to fully dissipate.
   ⚠Even after depressurization, some fuel will drain from lines when disconnected. Have shop rags ready to catch spillage.
2. 2

   Access fuel tank area
   Position yourself under the rear of the vehicle with adequate lighting. Identify the fuel tank—it is a saddle-style tank that wraps around the driveshaft tunnel. Locate the fuel filler hose and vent lines on the driver side rear, near the filler neck. Identify fuel supply and return hard lines running along the frame rail toward the front of the vehicle.
3. 3

   Drain remaining fuel from tank
   Using an approved hand pump or siphon, insert hose through fuel filler neck and drain as much fuel as practical into approved gasoline containers. The Viper fuel tank capacity is approximately 18.5 gallons; drain until less than 2 gallons remain to reduce weight and spillage risk. Cap containers immediately and move away from work area.
4. 4

   Disconnect fuel filler neck and vent lines
   Locate the rubber fuel filler hose connecting the filler neck to the tank inlet. Loosen the hose clamp at the tank end using a socket or screwdriver. Slide hose off tank inlet—fuel residue will drip, so have rags ready. Disconnect the vent line from the tank by releasing its clamp and pulling the hose free. Cap or plug openings to prevent contamination.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
5. 5

   Disconnect fuel supply and return lines
   Locate the fuel supply and return quick-disconnect fittings where hard lines meet flexible hoses near the front of the tank. Using the appropriate fuel line disconnect tool, depress the locking tabs and pull the lines apart. Fuel will drain from lines—catch with rags or container. Inspect O-rings in fittings and discard for replacement. Cap open lines to prevent dirt entry and fuel spillage.
   ⚠Fuel line disconnect tools are line-size specific. Using incorrect tool can damage fittings.
6. 6

   Disconnect fuel pump module electrical connector
   Locate the fuel pump module electrical connector on top of the fuel tank, accessible from underneath. The connector is a multi-pin weatherpack-style connector. Depress the locking tab and pull connector halves apart. Inspect connector terminals for corrosion—clean if necessary before reassembly.
7. 7

   Support fuel tank with floor jack
   Position a floor jack with a wide wood block (minimum 12 inches square, 2-inch thick) or fuel tank adapter under the center of the fuel tank. Raise jack until it just contacts tank and provides light support—do not lift tank yet, just support its weight. Ensure jack is stable and centered.
8. 8

   Remove fuel tank mounting straps
   Locate the two fuel tank mounting straps that secure the tank to the chassis. Each strap is secured at the front and rear with bolts that thread into frame brackets. Remove the mounting bolts (verify strap and bolt count against Mopar service documentation) using appropriate socket. Support straps as you remove final bolts—they are heavy and spring-loaded. Once bolts are removed, swing straps down and out of the way.
   ⚠Tank straps are under tension and will swing down forcefully when final bolt is removed. Keep hands clear of pinch points.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
9. 9

   Lower fuel tank
   With jack supporting tank and all connections disconnected, slowly lower the jack while guiding the tank down. Lower tank approximately 12-18 inches to expose the top surface where fuel pump module is mounted. Do not fully remove tank from vehicle—partial lowering provides sufficient access. Ensure no lines or wiring are pinched or binding as tank lowers.
10. 10

    Clean fuel pump module access area
    The fuel pump module is mounted on top of the fuel tank with a large lock ring. Before removing, clean the entire area around the lock ring and module flange thoroughly using shop rags and compressed air if available. Any dirt or debris that falls into the tank during pump removal will contaminate the fuel system. Wipe the lock ring, module flange, and surrounding tank surface until completely clean and dry.
11. 11

    Remove fuel pump module lock ring
    Insert the fuel pump lock ring spanner tool into the notches on the lock ring. The lock ring rotates counterclockwise to remove. Strike the spanner handle sharply with a mallet or apply steady force with a breaker bar (depending on tool design) to break the lock ring free—it may be tight. Rotate lock ring counterclockwise until it can be lifted free. Set lock ring aside and inspect its O-ring seal—replace if worn, compressed, or damaged.
    ⚠Do NOT use a hammer and punch to rotate lock ring, as this can damage the ring teeth or create sparks near fuel vapors. Use proper lock ring spanner tool.
    Torque spec

    Fuel Pump Lock Ring68 Nm (50 lb-ft)
12. 12

    Remove fuel pump module assembly
    Carefully lift the fuel pump module assembly straight up and out of the fuel tank. The module includes the pump, fuel level sender, and float arm assembly—the float arm may be extended and will need to be tilted to clear the tank opening. Tilt the module slightly to angle the float arm through the opening without bending it. Fuel will drain from the module—allow it to drain back into tank or into a container. Remove and discard the large O-ring seal from the tank opening flange.
    ⚠The fuel level sender float arm is delicate. Bending or damaging it will cause inaccurate fuel gauge readings.
13. 13

    Inspect tank interior and prepare new module
    With module removed, inspect the fuel tank interior opening for debris, rust, or contamination. If debris is visible, it may be necessary to remove tank completely for cleaning—this is beyond scope of this procedure but should be noted. Unpack new fuel pump module and verify it matches the original configuration (pump inlet orientation, float arm length, electrical connector type). Install the new O-ring seal onto the new module flange—lubricate lightly with clean engine oil or gasoline for easier installation.
    ℹ️Do NOT reuse the old O-ring seal. Reuse will cause fuel leaks and potential fire hazard.
14. 14

    Install new fuel pump module
    Carefully lower the new fuel pump module into the tank opening, tilting as necessary to guide the float arm assembly through without bending. Align the module flange with the tank opening, ensuring the O-ring seal seats properly in the groove. Rotate the module so that the alignment tab (if present) matches the tank's indexing feature, and the fuel outlet port is correctly oriented toward the supply line. Press module down firmly to fully seat O-ring.
15. 15

    Install and torque fuel pump lock ring
    Position the lock ring over the module flange, aligning it with the tank threads or locking tabs. Using the lock ring spanner tool, rotate the lock ring clockwise while keeping downward pressure on the module to ensure proper seating. Tighten lock ring per the Mopar service manual specification (verify exact value from OEM documentation; do not overtighten plastic lock rings), or follow tool manufacturer's torque procedure. Verify lock ring is fully seated and secure—it should not rotate by hand.
    Torque spec

    Fuel Pump Lock Ring68 Nm (50 lb-ft)
16. 16

    Raise fuel tank into position
    Raise the floor jack slowly to lift the fuel tank back into its mounted position against the chassis. Guide the tank carefully to avoid pinching any lines or wiring. Align the tank mounting strap bolt holes with the frame brackets. Stop when tank is fully seated and strap holes align.
17. 17

    Install fuel tank mounting straps and torque bolts
    Swing the two fuel tank mounting straps back up into position around the tank. Insert mounting bolts through strap ends into frame brackets—hand-thread bolts to avoid cross-threading. Once all mounting bolts are started, torque each bolt to the Mopar-specified value (verify exact torque and bolt count from OEM documentation), tightening evenly to ensure balanced strap tension.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)
18. 18

    Reconnect fuel pump electrical connector
    Reconnect the fuel pump module electrical connector by aligning the connector halves and pressing together until the locking tab clicks into place. Tug gently on connector to verify it is fully latched—it should not pull apart.
19. 19

    Reconnect fuel supply and return lines
    Install new O-rings onto the fuel line fittings—lubricate lightly with clean engine oil or gasoline. Push quick-disconnect fittings onto the fuel pump module ports until they click and lock. Tug on each line to verify it is secure—lines should not pull free. The fuel lines on this vehicle use quick-disconnect fittings; ensure each is fully seated and locked. If any threaded fittings are present, torque to the Mopar-specified value from OEM documentation.
    Torque spec

    Fuel Line Fittings25 Nm (18 lb-ft)
20. 20

    Reconnect fuel filler neck and vent lines
    Slide the fuel filler hose back onto the tank inlet and position hose clamp over the overlap area. Tighten hose clamp to 3.0 Nm (2 lb-ft)—snug but not over-tightened to avoid damaging hose. Reconnect vent line to tank vent fitting and secure its clamp to same specification.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
21. 21

    Reinstall fuel pump relay and reconnect battery
    Reinstall the fuel pump relay into the power distribution center—press firmly until seated. Reconnect the negative battery cable to battery post and tighten securely. Turn ignition key to RUN position (do not crank engine) for 5 seconds, then OFF. Repeat this cycle 3-4 times to allow fuel pump to prime the system and build pressure. Listen for fuel pump operation during each cycle—it should run for 2-3 seconds then stop.
22. 22

    Inspect for fuel leaks
    While ignition is in RUN position and fuel system is pressurized, carefully inspect all fuel connections: pump module lock ring seal, fuel line connections at module, filler hose, and vent line. Look for any signs of fuel seepage or dripping. Check underneath tank for drips. If any leaks are found, depressurize system, disconnect battery, and correct the leak before proceeding. Do not start engine if leaks are present.
    ⚠️ANY fuel leak is a fire hazard. Do not attempt to start or operate vehicle until all leaks are corrected.

Reassembly

1. Remove floor jack from under fuel tank and lower vehicle from jack stands.
2. Refill fuel tank with fresh gasoline—add at least 5 gallons to ensure adequate fuel for pump operation and leak testing.
3. Start engine and allow to idle. Monitor fuel system connections and tank area for leaks during first 5 minutes of operation.
4. Verify fuel gauge operation by observing that gauge reads appropriately for fuel level added.

Verification

• With engine running, verify no fuel odor in cabin or near fuel tank area.
• Confirm fuel pump operates normally—no excessive noise or whining from tank area.
• Check fuel gauge reads correctly and responds to fuel level changes (add known quantity of fuel and verify gauge moves appropriately).
• Verify no fuel leaks at module lock ring, fuel line connections, or filler neck after first drive cycle.
• Monitor for diagnostic trouble codes related to fuel system—if check engine light illuminates, scan for codes and address before returning vehicle to service.

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