Fuel Pump Module

Replace the fuel pump module assembly in a 2008 Dodge Viper, including lowering the fuel tank, disconnecting lines, and installing a new pump module.

Warnings

Tools required

Parts

• Fuel pump module assembly × 1 — Use OEM Mopar specification for 2008 Viper
• Fuel pump module O-ring/seal × 1 — Usually included with pump module
• Fuel tank strap hardware kit (if corroded) × 1 — Inspect before ordering

Preparation

1. Park vehicle on level, stable ground in a well-ventilated area away from any ignition sources
2. Ensure fuel tank is less than 1/4 full. If more than 1/4 full, siphon or drive vehicle until fuel level is low to reduce weight and spillage risk
3. Disconnect negative battery cable and isolate to prevent accidental reconnection
4. Wait minimum 10 minutes after battery disconnect to allow fuel system pressure to partially dissipate
5. Raise vehicle on jack stands at all four corners to provide adequate working clearance under fuel tank area
6. Position fire extinguisher within immediate reach of work area
7. Place fuel catch pan and absorbent shop towels under fuel tank area before beginning work

Procedure

1. 1

   Relieve fuel system pressure
   Locate the fuel pump relay in the power distribution center (PDC) under the hood. Remove the fuel pump relay. Attempt to start the engine; it should crank but not start or run briefly then stall. Crank engine for an additional 5 seconds to ensure fuel rail is depressurized. Turn ignition off. This reduces fuel system pressure to near-zero.
2. 2

   Access and disconnect fuel filler neck
   Working from the driver-side rear quarter area, locate the fuel filler neck where it connects to the tank. Loosen the hose clamp securing the filler neck to the tank inlet using a socket or screwdriver. Carefully twist and pull the filler neck away from the tank. Some residual fuel may drain; catch with shop towels. If present, disconnect the vent line from the filler neck area using the appropriate disconnect tool.
3. 3

   Disconnect fuel tank electrical connector
   Locate the main fuel pump module electrical connector near the top of the fuel tank. Press the locking tab and disconnect the harness connector. Push the connector up and away from the tank to prevent reconnection during tank lowering.
4. 4

   Disconnect fuel supply and return lines
   Identify the fuel supply line at the front of the fuel tank. Note that the 2008 Viper uses a returnless fuel system with in-tank pressure regulation, so a separate return line is typically NOT present; verify against the vehicle before expecting one. Place shop towels around the connection points to catch residual fuel. Use the appropriate size fuel line disconnect tool to release each quick-connect fitting. Press the tool onto the line, then pull the line straight out from the tank fitting. Expect 2-4 ounces of fuel to drain from each line. Plug or cap open lines to prevent contamination.
5. 5

   Support fuel tank with transmission jack
   Position a transmission jack or floor jack with a wide wood block (minimum 12 inches square) under the center of the fuel tank. Raise the jack until it just contacts the tank bottom with light pressure. The jack must stabilize the tank but not yet bear its full weight. Verify the tank is balanced and will not shift when straps are loosened.
6. 6

   Remove fuel tank mounting straps
   Locate the two fuel tank support straps that loop under the tank and bolt to the chassis on each side. Remove the rear mounting bolt from each strap. The straps will pivot downward from the front mounting point. Slowly lower the transmission jack 2-3 inches while guiding the straps out of the way. If the straps have front mounting bolts (design varies), remove those as well and set straps aside.
7. 7

   Lower fuel tank
   Slowly and carefully lower the transmission jack, watching for any remaining hoses, wires, or straps still attached to the tank. Lower the tank approximately 12-16 inches to provide access to the top of the fuel pump module. The tank does not need to be fully removed unless pump module access is obstructed. Keep the tank supported on the jack at all times.
8. 8

   Clean fuel pump module area
   Using shop towels, clean all dirt, debris, and corrosion from around the fuel pump module locking ring on top of the tank. This prevents contamination from falling into the tank during module removal. Do not use compressed air, as debris could blow into tank vents.
9. 9

   Remove fuel pump module locking ring
   The fuel pump module is secured by a large threaded locking ring. Using a brass punch or non-sparking drift and soft-face mallet, tap the locking ring counterclockwise at the tabs or notches. Work around the ring progressively to avoid binding. Once loose, unscrew the ring by hand and remove it completely. Set aside with the O-ring still attached if it comes off with the ring.
10. 10

    Remove fuel pump module assembly
    Carefully lift the fuel pump module assembly straight up and out of the tank opening. The module includes the pump, fuel level sender, and float arm assembly. Tilt the module slightly to maneuver the float arm and sender through the opening without bending components. Residual fuel will drain from the module; allow it to drain back into the tank or into a catch pan. Inspect the O-ring seal in the tank opening and remove if still in place.
11. 11

    Inspect tank interior and prepare for installation
    With the module removed, visually inspect the interior of the fuel tank opening for debris, rust, or contamination. Use a clean lint-free towel to wipe the sealing surface where the O-ring seats. Do not introduce any loose material into the tank. Verify the tank opening sealing surface is clean, smooth, and undamaged.
12. 12

    Install new fuel pump module
    Install the new O-ring seal onto the new fuel pump module or into the tank opening groove (depending on design). Ensure the O-ring is seated properly without twists or pinches. Carefully lower the new fuel pump module into the tank opening, aligning the orientation marks or tabs so the module seats correctly. Maneuver the float arm and sender assembly through the opening. Push the module fully down until it seats against the O-ring.
13. 13

    Install and tighten locking ring
    Place the locking ring over the fuel pump module and thread it clockwise by hand until finger-tight. Using the brass punch and soft-face mallet, tap the locking ring clockwise at the tabs to tighten securely. The ring should be snug and the module should not rotate or lift. Do not overtighten, as this can damage the plastic tank flange.
14. 14

    Raise and secure fuel tank
    Carefully raise the fuel tank using the transmission jack, guiding it back into position against the chassis mounting points. Align the tank with the fuel filler neck and all mounting locations. Reinstall the fuel tank support straps and secure with the mounting bolts. Tighten the strap bolts in an alternating pattern to draw the tank up evenly. Remove the transmission jack once straps are fully secured.
15. 15

    Reconnect fuel lines and electrical
    Reconnect the fuel supply and return lines to the tank fittings. Push each line straight into the quick-connect fitting until you hear and feel a positive click. Tug gently on each line to verify it is locked. Reconnect the fuel pump module electrical harness connector and verify the locking tab engages. Reconnect the fuel filler neck hose to the tank inlet and secure with the hose clamp. If equipped, reconnect the vent line.
16. 16

    Prime fuel system and check for leaks
    Reinstall the fuel pump relay in the PDC. Reconnect the negative battery cable. Turn the ignition key to the ON position (do not crank) for 5 seconds to activate the fuel pump and prime the system. Turn key OFF, wait 5 seconds, then ON again. Repeat this cycle 3-4 times. Inspect all fuel line connections, the pump module locking ring, and filler neck for any signs of fuel leakage. Address any leaks immediately before proceeding.

Reassembly

1. Ensure all fuel line quick-connect fittings are fully seated and locked with audible clicks
2. Verify fuel tank straps are tightened evenly and fuel tank is stable with no movement
3. Confirm fuel pump module locking ring is fully tightened and O-ring is properly seated
4. Double-check that all electrical connectors are engaged and locked

Verification

• With ignition in ON position (engine not running), verify fuel pump activates for 2-3 seconds (listen for pump hum from rear of vehicle)
• Start engine and allow it to idle. Monitor for smooth operation with no fuel starvation symptoms
• Inspect all fuel connections under the vehicle for leaks while engine is running
• Rev engine to 2000-3000 RPM briefly and verify no fuel pressure loss or leaks develop
• Verify fuel gauge reads accurately and matches actual tank level
• Test drive vehicle and confirm normal acceleration and no fuel delivery issues under load

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