Fuel Pump Module

Replace the fuel pump module in a 1992 Dodge Viper, including depressurizing the fuel system, removing the fuel tank, extracting the pump assembly, and reinstalling with new seals.

Warnings

Tools required

Parts

• Fuel pump module assembly × 1 — Use OEM specification
• Fuel pump lock ring O-ring/seal × 1 — Use OEM specification
• Fuel line O-rings × 4 — Use OEM specification
• Fuel tank strap hardware (if corroded) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground outdoors or in a well-ventilated garage. Ensure no ignition sources within 50 feet. Set parking brake and chock rear wheels.
2. Disconnect negative battery cable and isolate it away from the battery terminal to prevent sparks.
3. Allow engine to cool completely if recently driven. Hot components can ignite fuel vapors.
4. Position Class B fire extinguisher within immediate reach of work area.
5. Relieve fuel system pressure by locating the fuel pump relay in the power distribution center (under hood), removing it, and attempting to start the engine. Engine will crank but not start, or start briefly then stall. Crank for 5-10 seconds to ensure pressure is relieved.
6. Drain fuel tank to below 1/4 capacity to reduce weight and spillage. Use approved hand pump or siphon into FM-rated fuel storage containers. Running tank near-empty before starting is strongly recommended.
7. Raise rear of vehicle with floor jack and support on jack stands rated for vehicle weight. Verify stability before working underneath.

Procedure

1. 1

   Disconnect fuel filler hose and vent lines
   Locate the fuel filler neck on the driver-side rear quarter. Using appropriate wrenches, loosen the hose clamps securing the filler hose to the filler neck and to the fuel tank inlet. Disconnect the filler hose from the tank. Disconnect any vapor vent lines from the tank using fuel line disconnect tools. Cap or plug openings to prevent debris entry and fuel spillage.
   Torque spec

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

   Disconnect fuel supply and return lines
   Locate the fuel supply and return hard lines at the front of the fuel tank. These are quick-disconnect fittings. Use fuel line disconnect tools to release the fittings and separate the lines from the tank. Have a drain pan ready to catch residual fuel (expect 100-200ml spillage per line). Inspect the hard line fittings for damage. Plug the open lines to prevent contamination.
   ⚠Even after pressure relief, residual fuel will drain from lines. Position drain pan directly under fittings before disconnecting.
3. 3

   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 wiring harness from the pump module. Secure the harness away from the tank to prevent damage during removal.
   ℹ️Do not pull on wires. Press the connector locking tab firmly to release.
4. 4

   Support fuel tank with transmission jack
   Position a transmission jack or suitable adjustable support under the center of the fuel tank. Raise the jack until it just contacts the tank bottom, providing firm support without lifting the tank. Place a wide board or rubber pad between the jack and tank to distribute load and prevent puncture. The tank must be securely supported before removing straps.
   ⚠️Tank must be fully supported before loosening straps. Inadequate support will cause the tank to fall, creating crush and fire hazards.
5. 5

   Remove fuel tank strap mounting bolts
   Locate the fuel tank support straps (verify quantity and fastening arrangement against OEM documentation). Each strap is secured at its frame mounting point. Using a socket wrench, remove both mounting bolts. Lower the transmission jack slowly (1-2 inches) to angle the tank and verify strap release. The tank straps should pivot away from the tank body. Carefully lower the tank approximately 6 inches to access the top of the module.
   ⚠Lower the tank slowly and ensure no wiring or hoses are still connected. Stop immediately if resistance is felt.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
6. 6

   Clean fuel pump module area
   With the tank lowered for access, use a wire brush (brass or nylon only, never steel near fuel) to clean debris and dirt from around the fuel pump module lock ring and surrounding tank surface. Wipe the area clean with a lint-free cloth. Any contamination that falls into the tank when the module is removed will damage the new pump.
   ⚠Do not use compressed air, which will blow debris into the tank opening when the module is removed.
7. 7

   Remove fuel pump module lock ring
   Using a fuel pump lock ring tool (large spanner wrench or brass punch and hammer), rotate the lock ring counterclockwise to unthread it from the tank flange. The ring has multiple tangs for tool engagement. If using a brass punch, tap gently in a counterclockwise direction. Once loose, unscrew the lock ring completely by hand and remove it. Set aside with the O-ring seal still attached for inspection.
   ⚠Never use steel punches or hammers directly on the lock ring. Use brass or aluminum tools only to prevent sparks.
   Torque spec

   Fuel Pump Lock Ring68 Nm (50 lb-ft)
8. 8

   Extract fuel pump module from tank
   Carefully lift the fuel pump module straight up and out of the tank opening. The module includes the pump, fuel level sender, strainer, and connecting hoses. Tilt the module as needed to clear the tank opening, but avoid bending the fuel level sender float arm. Residual fuel will drain from the module; hold it over the tank opening until draining stops. Place the old module in a drain pan. Immediately cover the tank opening with a clean shop towel or plastic cover to prevent contamination.
   ⚠The fuel level sender arm is fragile. Do not bend or force the module during extraction.
9. 9

   Inspect tank interior and prepare new module
   With the tank opening accessible, visually inspect the interior for rust, debris, or contamination. If significant debris is present, the tank should be removed completely for thorough cleaning (not part of this procedure). Remove the new fuel pump module from packaging. Inspect the new O-ring seal and ensure it is properly seated in the module flange groove. Lubricate the O-ring lightly with clean gasoline (never petroleum jelly or oil-based lubricants).
   ℹ️Do not use petroleum-based lubricants on fuel system O-rings. They will cause swelling and seal failure.
10. 10

    Install new fuel pump module
    Lower the new fuel pump module into the tank opening, orienting it correctly (alignment marks or key features prevent incorrect installation). Guide the module straight down, tilting as necessary to clear the opening without damaging the fuel level sender. Once fully seated, verify the module flange is flush against the tank surface and the O-ring is not pinched or displaced.
    ⚠Ensure correct orientation before installing. Forcing the module will damage the float arm or internal components.
11. 11

    Install and torque fuel pump lock ring
    Place the lock ring over the module flange and thread it clockwise by hand until finger-tight. Using the fuel pump lock ring tool, tighten the lock ring to the factory-specified torque (verify against OEM service documentation, as many lock rings are hand-tightened to a stop rather than a high torque value). Ensure even seating around the entire circumference. The module should be firmly secured with no movement.
    ⚠Over-torquing the lock ring will crack the tank flange. Use a calibrated torque wrench.
    Torque spec

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

    Reconnect fuel pump electrical connector
    Reconnect the wiring harness to the fuel pump module electrical connector on top of the tank. Press firmly until the locking tab clicks into place. Tug gently to verify secure connection.
13. 13

    Raise and secure fuel tank
    Using the transmission jack, carefully raise the fuel tank back into position against the vehicle underbody. Align the tank with the mounting points and ensure no wiring or hoses are pinched. Swing the fuel tank straps back into position over the tank. Install the strap mounting bolts and tighten to the factory-specified torque (verify against OEM service documentation).
    ⚠Verify all hoses and wiring are clear before final tightening. Check that straps are not twisted.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)
14. 14

    Reconnect fuel supply and return lines
    Install new O-rings on the fuel supply and return line fittings (discard old O-rings). Lightly lubricate the new O-rings with clean gasoline. Push the quick-disconnect fittings onto the tank ports until they click into place. Tug on each line to verify secure engagement. If threaded fittings are used instead of quick-disconnects, torque to the factory-specified value (verify against OEM service documentation).
    ⚠Always replace O-rings when disconnecting fuel fittings. Reused O-rings will leak.
    Torque spec

    Fuel Line Fittings25 Nm (18 lb-ft)
15. 15

    Reconnect filler hose and vent lines
    Reconnect the fuel filler hose to the tank inlet and tighten the hose clamps securely until the hose is sealed against the neck without deforming the hose. Reconnect any vapor vent lines, ensuring quick-disconnect fittings click fully into place. Remove any plugs or caps installed during disassembly.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)

Reassembly

1. Reconnect the negative battery cable.
2. Refill the fuel tank with at least 5 gallons of fresh gasoline to ensure adequate pump submersion and cooling.
3. Reinstall the fuel pump relay in the power distribution center.
4. Before starting the engine, cycle the ignition key to ON (not START) for 2 seconds, then OFF. Repeat 3-4 times to prime the fuel system and allow the pump to pressurize the lines.
5. Visually inspect all fuel line connections and the area around the fuel pump module for leaks during priming.

Verification

• Start the engine and allow it to idle. Listen for unusual fuel pump noise or rough running that could indicate air in the lines or a faulty installation.
• With the engine running, inspect all fuel line connections, the filler hose, vent lines, and the area around the fuel pump module lock ring for fuel leaks. Use a flashlight and look carefully; even small leaks are dangerous.
• Check fuel gauge operation to verify the fuel level sender is functioning correctly.
• Turn off the engine and re-inspect all connections after 5 minutes. Fuel system pressure remains high even with the engine off; leaks may appear after initial pressurization.
• Test drive the vehicle and verify normal fuel delivery under load and acceleration. Monitor the fuel gauge for accurate reading.
• After test drive, perform a final leak inspection of all fuel system components while the system is hot and pressurized.

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