Fuel Tank

Complete removal and replacement of the fuel tank on a 1992 Dodge Viper, including fuel system depressurization, tank strap removal, and fuel line disconnection.

Warnings

Tools required

Parts

• Fuel tank (if replacement required) × 1 — Mopar 4684474 or equivalent
• Fuel tank strap set × 1 — Use OEM specification if corroded
• Fuel filler neck O-ring × 1 — Use OEM specification
• Fuel line O-rings × 4 — Use OEM specification
• Fuel pump module gasket × 1 — Use OEM specification if disturbed
• Vent line grommets × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground outdoors or in a well-ventilated shop with no ignition sources present
2. Ensure fuel tank is no more than 1/4 full; if necessary, drive vehicle to consume fuel to this level
3. Place Class B fire extinguisher within immediate reach of work area
4. Disconnect negative battery cable and isolate it away from battery terminal
5. Allow exhaust system to cool completely (minimum 2 hours after last operation)
6. Chock front wheels securely
7. Raise rear of vehicle using floor jack and support on jack stands rated for vehicle weight, positioned at factory lift points on rear frame rails
8. Verify vehicle is stable and will not shift during work

Procedure

1. 1

   Relieve fuel system pressure
   Remove fuel filler cap to relieve tank pressure. Locate the fuel pump relay (refer to the 1992 Viper service manual for exact location, typically in the power distribution center under the hood). Remove the fuel pump relay from its socket. Attempt to start the engine; it should run briefly and stall as remaining fuel in lines is consumed. Crank engine for 5 additional seconds to ensure all pressure is relieved. Verify zero pressure by connecting a fuel pressure gauge to the Schrader valve on the fuel rail and confirming 0 PSI reading. Reinstall fuel pump relay (it will be removed again during tank removal but is needed to verify pressure relief).
2. 2

   Remove fuel filler cap and prepare for fuel transfer
   Confirm fuel filler cap is removed. Position approved fuel storage containers nearby. Using a hand-operated siphon pump inserted through the filler neck, remove as much fuel as possible from the tank. Transfer fuel to approved storage containers only; never use unapproved containers. Continue siphoning until no more fuel can be extracted. Expect to remove 5-8 gallons even from a 1/4-full tank. This step is critical to reduce tank weight to a safe handling level.
3. 3

   Access fuel tank from below
   Position yourself under the rear of the vehicle. Locate the fuel tank positioned at the rear of the vehicle (verify exact position relative to the rear axle in the 1992 Viper service manual). Identify the fuel pump module electrical connector on top of the tank, the fuel supply and return lines at the front of the tank, the fuel filler neck on the driver side rear, the vent lines, and the two fuel tank retaining straps crossing underneath the tank. Have shop light and drain pan ready for next steps.
4. 4

   Disconnect fuel pump electrical connector
   Locate the fuel pump module electrical connector on top of the fuel tank. Press the locking tab and disconnect the electrical connector. Move the connector and wiring harness aside, securing it away from the tank to prevent damage during removal.
5. 5

   Disconnect fuel supply and return lines
   Position drain pan under the fuel line connections at the front of the tank. The Viper uses quick-disconnect fittings on the fuel supply and return lines. Using the appropriate fuel line disconnect tool for the fitting size, disconnect the fuel supply line (larger diameter) and fuel return line from the fuel pump module. Expect residual fuel to drain from lines into pan. Immediately cap or plug the open fuel lines to prevent contamination and further leakage. Inspect O-rings in fittings and note their condition for replacement.
6. 6

   Disconnect fuel filler neck
   At the driver side rear of the tank, locate the fuel filler neck connection to the tank. Loosen the hose clamp securing the filler neck to the tank inlet using appropriate socket or screwdriver. Slide clamp back on filler neck. Twist and pull the filler neck to disconnect it from the tank inlet. Residual fuel will drain; have drain pan positioned to catch spillage. Inspect the filler neck O-ring/seal for damage.
   Torque spec

   Filler Neck Clamp4 Nm (3 lb-ft)
7. 7

   Disconnect vent lines
   Locate the fuel tank vent lines connecting to the top or side of the tank. The 1992 Viper uses 2 vent line connections. Loosen clamps or press release tabs on quick-disconnect fittings to disconnect vent lines from tank. Move lines aside and cap open ports on tank to prevent debris entry.
8. 8

   Support fuel tank with transmission jack
   Position transmission jack or adjustable floor jack with a wide wooden block under the center of the fuel tank. Raise jack until it just contacts the tank bottom, providing slight support but not lifting the tank. The tank should remain resting on its mounting straps. Ensure jack is centered and stable before proceeding. This support prevents the tank from falling when straps are released.
9. 9

   Remove fuel tank strap bolts
   Locate the 2 fuel tank retaining straps that loop under the tank and bolt to frame brackets on each side. Each strap has 1 bolt at each end (4 bolts total). Using penetrating oil if necessary, remove the 4 strap-to-frame mounting bolts. Support straps as final bolts are removed to prevent them from falling. Once all bolts are removed, pivot straps downward away from tank.
   Torque spec

   Tank Strap Bolts35 Nm (26 lb-ft)
10. 10

    Lower and remove fuel tank
    With all connections disconnected and straps removed, slowly lower the transmission jack to lower the fuel tank. Guide the tank as it descends, ensuring no remaining lines, wires, or hoses are still connected. Watch for any vent lines or ground straps that may have been missed. Once tank is clear of the vehicle frame, lower jack completely and carefully maneuver tank out from under vehicle. Use assistance if needed; even a drained tank is heavy and awkward. Place tank on ground in safe location away from any ignition sources.
11. 11

    Inspect and clean mounting area
    With tank removed, inspect the tank mounting straps, frame brackets, and mounting surfaces for corrosion, damage, or debris. Wire brush rust from straps and frame mounting points. Inspect rubber isolators or cushions (if present) between straps and tank for deterioration. Check frame rails for fuel staining indicating previous leaks. If installing a new tank, transfer the fuel pump module from old tank to new tank per manufacturer instructions, using new gasket.
12. 12

    Install fuel tank into position
    Position the fuel tank (new or serviced original) on the transmission jack. Carefully raise jack and maneuver tank up into position between frame rails. Align tank so mounting strap brackets align with frame mounting points and all line connection points are oriented correctly. Raise tank until it seats against frame rail contact points. Hold tank in position with jack.
13. 13

    Install fuel tank straps and bolts
    Swing the 2 fuel tank retaining straps up into position, looping them under the tank. Align strap ends with frame bracket mounting holes. Install the 4 strap mounting bolts finger-tight initially. Ensure straps are not twisted and are properly seated in frame brackets. Once all 4 bolts are started, tighten them in a cross pattern (alternate side-to-side) to specified torque to evenly load the tank. Lower and remove transmission jack once straps are secured.
    Torque spec

    Tank Strap Bolts35 Nm (26 lb-ft)
14. 14

    Reconnect vent lines
    Reconnect the 2 fuel tank vent lines to their ports on the tank. Install new grommets or seals if originals are damaged. Ensure connections are fully seated and clamps (if equipped) are tightened securely. Verify lines are routed correctly and are not kinked or pinched.
15. 15

    Reconnect fuel filler neck
    Install new filler neck O-ring onto the tank inlet if original is damaged or hardened. Slide filler neck hose clamp into position on filler neck. Push filler neck firmly onto tank inlet, ensuring it seats completely over the O-ring. Position hose clamp over connection area and tighten to specified torque. Verify connection is secure with no gaps.
    Torque spec

    Filler Neck Clamp4 Nm (3 lb-ft)
16. 16

    Reconnect fuel supply and return lines
    Install new O-rings on fuel line fittings. Lubricate O-rings lightly with clean engine oil. Connect fuel supply line (larger diameter) and fuel return line to fuel pump module ports, pushing firmly until quick-disconnect fittings click and lock into place. Tug gently on each line to verify secure connection. If lines use threaded fittings instead of quick-disconnects, tighten to specified torque using appropriate wrench.
    Torque spec

    Fuel Line Fittings25 Nm (18 lb-ft)
17. 17

    Reconnect fuel pump electrical connector
    Reconnect the electrical connector to the fuel pump module on top of the tank. Ensure connector locks fully with audible click. Verify locking tab engages completely. Route wiring harness so it is not pinched or stretched.
18. 18

    Reconnect battery and perform initial system check
    Reconnect negative battery cable. Confirm fuel pump relay is installed in power distribution center. Turn ignition key to ON position (do not start engine). Listen for the fuel pump to run briefly, pressurizing the system (behavior per 1992 Viper service manual). Cycle the key OFF then ON several times to fully pressurize the fuel system. While system is pressurized, inspect all fuel line connections, filler neck, and vent lines from below for any signs of leakage. Address any leaks immediately before proceeding.

Reassembly

1. Installation follows removal in reverse order
2. Always use new O-rings on all fuel line connections
3. Replace fuel filler neck seal if original shows any cracking or hardness
4. Ensure all quick-disconnect fittings are fully seated and locked
5. Tighten all fasteners to specified torque values in the order described
6. Verify fuel tank straps are not twisted and load is evenly distributed

Verification

• With vehicle still raised and supported, turn ignition to ON position multiple times to pressurize fuel system; verify no fuel leaks at tank connections, filler neck, pump module, or vent lines
• Lower vehicle to ground and remove jack stands
• Add 2-3 gallons of fresh fuel through filler neck
• Start engine and allow it to idle; monitor for smooth operation and verify no fuel odor or visible leaks under vehicle
• Turn engine off and perform final leak inspection of all connections made during procedure
• Test drive vehicle briefly; recheck all connections after test drive for any seepage or leaks
• Monitor fuel system operation over next several days for any delayed leak development

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