Fuel Pump

Replacement of the fuel pump module in a 2008 Dodge Viper 8.4L V10, requiring fuel tank lowering for access to the in-tank pump assembly.

Warnings

Tools required

Parts

• Fuel pump module assembly × 1 — Use OEM Mopar specification for 2008 Viper 8.4L
• Fuel pump module O-ring seal × 1 — Typically included with pump module
• Fuel tank strap hardware (if corroded) × 1 — Inspect and replace as needed

Preparation

1. Park vehicle on level ground in a well-ventilated area away from any ignition sources. Ensure adequate overhead clearance if using a lift.
2. Have a Class B fire extinguisher immediately accessible before beginning work.
3. Allow engine to cool completely if vehicle has been recently operated (minimum 1 hour).
4. Relieve fuel system pressure: Remove fuel pump relay (located in power distribution center near battery), then attempt to start engine and let it run until it stalls. Attempt to restart 2-3 more times to ensure pressure is relieved.
5. Disconnect negative battery cable and secure away from battery post. Wait 2 minutes for airbag system capacitor discharge.
6. Drain fuel tank to 1/4 full or less to reduce weight and spillage. Use approved fuel storage containers and follow local regulations for fuel handling.
7. Raise vehicle on lift or securely support on jack stands at all four corners. Vehicle must be level and stable with sufficient clearance to lower fuel tank (minimum 18 inches recommended).
8. Place absorbent pads or drip pans under fuel tank area to catch residual fuel spillage.

Procedure

1. 1

   Access fuel tank from underneath vehicle
   Position yourself under the vehicle with adequate lighting. Locate the fuel tank (verify exact location per 2008 Viper FSM; on this platform the tank is mounted at the rear of the vehicle in the chassis structure). Identify the fuel pump module access area on top of the tank, visible between the tank and body. Note the routing of fuel lines, EVAP lines, and electrical connectors before proceeding.
2. 2

   Disconnect fuel filler neck and vent hoses
   Locate the fuel filler neck hose connected to the tank inlet on the driver side rear of tank. Use appropriate wrench or socket to loosen the hose clamp securing the filler neck hose to the tank. Slide clamp back and carefully work the hose off the tank inlet. Fuel may spill from the hose; have drain pan ready. Locate and disconnect the vent hose from the tank using the same method. Cap or plug openings if available to minimize vapor release.
3. 3

   Disconnect fuel supply and return lines
   Locate the fuel supply and return lines connected to the fuel pump module on top of the tank. These are quick-disconnect fittings. Using the appropriate fuel line disconnect tool, depress the internal release mechanism while pulling the line straight off the module fitting. Expect residual fuel to drain from lines; use drain pan and shop towels. Once disconnected, move lines aside and secure away from tank to prevent damage during lowering. Check for EVAP canister lines and disconnect any additional vapor lines using the same quick-disconnect method.
4. 4

   Disconnect fuel pump electrical connector
   Locate the fuel pump module electrical connector on top of the tank. The connector has a locking tab or slide lock. Press the release tab while pulling the connector straight up and away from the module. Ensure the connector and wiring harness are routed clear of the tank and will not be pinched during tank lowering. Inspect connector terminals for corrosion; clean if necessary during reassembly.
5. 5

   Support fuel tank with transmission jack
   Position a transmission jack or floor jack with wide wooden board under the center of the fuel tank. Raise jack until it just contacts the tank bottom with light pressure, supporting the tank weight but not lifting it. Ensure jack is stable and tank is balanced on jack surface. Lower the tank only as far as needed for pump module access (verify exact clearance and whether full tank removal is required per 2008 Viper FSM).
6. 6

   Remove fuel tank strap bolts
   Locate the fuel tank retaining strap(s) securing the tank to the chassis (verify exact strap and bolt count per 2008 Viper FSM). Note the bolt locations before removal. Using appropriate socket, remove the 2 strap bolts securing the straps to the chassis mounting points. The straps may be spring-loaded; control strap movement as bolts are removed. Once bolts are removed, carefully pivot straps down and away from tank, or remove straps completely if clearance allows.
   Torque spec

   Tank Strap Bolts35 Nm (26 lb-ft)
7. 7

   Lower fuel tank for pump access
   Slowly and carefully lower the transmission jack, allowing the fuel tank to descend. Lower tank approximately 8-12 inches or until the fuel pump module top is clearly accessible and you have sufficient working room around the lock ring. Continuously monitor all lines and wiring to ensure nothing is pulled tight or snagged. Stop lowering if any resistance is felt and verify all connections were properly disconnected. The tank does not need to be fully removed for this procedure.
8. 8

   Clean fuel pump module area
   Using clean shop towels, thoroughly clean the area around the fuel pump module lock ring on top of the tank. Remove all dirt, debris, and corrosion that could fall into the tank during module removal. This step is critical to prevent contamination of the fuel system. Use compressed air if available, directing debris away from the tank opening.
9. 9

   Remove fuel pump module lock ring
   Using the appropriate fuel tank lock ring tool for this platform (verify correct Miller special tool number per 2008 Viper FSM), engage the tool tabs into the lock ring slots. The lock ring turns counterclockwise to remove. Apply firm, steady pressure counterclockwise to break the ring free. It may be tight due to corrosion or fuel residue. Once loosened, unthread the lock ring completely and lift it off the tank. Set lock ring aside in a clean area and inspect threads for damage.
   Torque spec

   Fuel Pump Module Lock Ring80 Nm (59 lb-ft)
10. 10

    Remove fuel pump module from tank
    Carefully lift the fuel pump module straight up and out of the tank opening. The module includes the pump assembly, fuel level sender, and pick-up strainer, all on a bracket assembly. Tilt the module as needed to clear the tank opening while keeping the strainer end inside the tank as long as possible to minimize fuel spillage. Once the module is clear, tilt it to drain residual fuel back into tank, then place module in a fuel-resistant drain pan. Note the orientation of the module for proper installation of the replacement.
11. 11

    Remove and inspect O-ring seal
    Locate the large O-ring seal in the groove on the top of the fuel tank opening. Use a plastic pry tool or gloved fingers to carefully remove the old O-ring from the groove. Inspect the groove for any damage, corrosion, or debris. Clean the groove thoroughly with a clean shop towel. Do not use solvents that could contaminate the fuel. The new O-ring should be included with the replacement pump module; do not reuse the old O-ring.
12. 12

    Prepare new fuel pump module
    Remove new fuel pump module from packaging and inspect for shipping damage. Verify that the new module matches the configuration of the old unit, including electrical connector orientation and fuel line fitting positions. Install the new O-ring seal onto the new module or into the tank groove, ensuring it is properly seated and not twisted. Lubricate the O-ring lightly with clean gasoline or petroleum jelly to ease installation.
13. 13

    Install new fuel pump module into tank
    Carefully lower the new fuel pump module into the tank opening. Align the module orientation to match the original position noted during removal. The module has indexing features or tabs that must align with slots in the tank opening. Once aligned, press the module firmly down into the tank until it seats against the O-ring and the top of the module is flush or slightly below the tank surface. Ensure the O-ring is not pinched or displaced during installation.
14. 14

    Install and torque fuel pump module lock ring
    Place the lock ring over the fuel pump module, aligning the threads with the tank threads. Thread the lock ring clockwise by hand until it is finger-tight and seated against the module. Using the fuel tank lock ring tool, tighten the lock ring clockwise to the manufacturer-specified torque (verify exact value per 2008 Viper FSM). This torque is critical to ensure proper seal and prevent fuel leaks. Verify the lock ring is evenly seated around its circumference.
    Torque spec

    Fuel Pump Module Lock Ring80 Nm (59 lb-ft)
15. 15

    Raise fuel tank into position
    Carefully raise the transmission jack, lifting the fuel tank back up toward its mounting position. Guide the tank up evenly, monitoring all electrical connectors, fuel lines, and hoses to ensure they route properly and do not snag or kink. Raise tank until the mounting strap bolt holes align with chassis mounting points. Do not allow the tank to hang on any lines or wiring.
16. 16

    Install fuel tank straps and torque bolts
    Position the fuel tank retaining straps over the tank and align the strap ends with the chassis mounting bolt holes. Install the strap bolts and thread by hand to ensure proper thread engagement. Using a torque wrench and appropriate socket, tighten the strap bolts to the manufacturer-specified torque (verify exact value per 2008 Viper FSM). Torque bolts in a cross pattern if applicable to ensure even strap tension. Verify tank is secure and properly positioned.
    Torque spec

    Tank Strap Bolts35 Nm (26 lb-ft)
17. 17

    Reconnect fuel pump electrical connector
    Route the fuel pump electrical connector back to the module on top of the tank. Align the connector with the module terminal and press firmly until it clicks into place. Verify the locking tab is fully engaged and the connector cannot be pulled off without depressing the release tab. Ensure wiring harness is routed away from sharp edges and heat sources.
18. 18

    Reconnect fuel supply and return lines
    Reconnect the fuel supply and return lines to the fuel pump module fittings. Push each line straight onto its respective fitting until you hear and feel a distinct click, indicating the quick-disconnect mechanism has locked. Pull gently on each line to verify it is secure and will not come off. Reconnect any EVAP canister lines or vapor lines using the same method. Ensure all lines are properly routed and not kinked or stressed.
19. 19

    Reconnect fuel filler neck and vent hoses
    Position the fuel filler neck hose onto the tank inlet and slide fully onto the fitting. Install the hose clamp and tighten securely using the appropriate tool. Ensure clamp is positioned over the reinforced section of the hose. Reconnect the vent hose to the tank using the same method. Verify both connections are secure and hoses are not kinked or twisted.
20. 20

    Perform fuel system leak test
    Remove jack and lower vehicle to ground or stable position. Reconnect negative battery cable. Turn ignition key to ON position (do not start engine) to activate fuel pump and pressurize the system. Listen for fuel pump operation for 2-3 seconds. Cycle ignition OFF and ON three times to fully pressurize system. Inspect all fuel line connections, pump module lock ring, and filler neck connections for any signs of fuel leakage. Use a flashlight and look carefully for wet spots or fuel drips. If any leaks are detected, depressurize system and correct the issue before proceeding.

Reassembly

1. Installation is included in the main procedure steps above, with critical torque specifications applied during installation.
2. After leak test is complete and no leaks are found, start the engine and allow it to idle. Monitor fuel pressure and check again for leaks with engine running.
3. Clear any diagnostic trouble codes related to fuel system if check engine light is illuminated after procedure.

Verification

• With engine running at idle, verify no fuel odor is present and no visible fuel leaks exist at pump module, fuel lines, or filler neck connections.
• Test drive vehicle and verify normal engine performance with no hesitation, stumbling, or fuel delivery issues.
• Monitor fuel gauge operation to confirm fuel level sender in new module is functioning correctly.
• Perform final inspection under vehicle after test drive to verify no fuel leaks have developed.
• Verify check engine light is not illuminated and no fuel system trouble codes are present using scan tool if available.

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