Fuel Pump

Replace the fuel pump module assembly on a 2014-2018 Chevrolet Silverado 1500 with 5.3L V8 engine by accessing the pump through the fuel tank access panel in the truck bed.

Warnings

Tools required

Parts

• Fuel pump module assembly × 1 — AC Delco MU2298 or equivalent
• Fuel pump module O-ring seal × 1 — Usually included with pump assembly
• Fuel line O-rings × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground in a well-ventilated area away from ignition sources
2. Ensure fuel tank is less than 1/4 full to minimize spillage (siphon fuel if necessary using approved pump and storage)
3. Disconnect negative battery cable and wait 2 minutes for airbag system to discharge
4. Remove cargo from truck bed and clean area around fuel tank access cover
5. Gather all tools, parts, and safety equipment before beginning
6. Have fire extinguisher rated for gasoline fires readily accessible

Procedure

1. 1

   Relieve fuel system pressure
   Locate the fuel pump fuse in the underhood fuse block (fuse #87, 15A). Remove the fuel pump fuse. Start the engine and allow it to run until it stalls from fuel starvation. Attempt to start the engine 2-3 more times to ensure all pressure is relieved. Turn ignition to OFF position. Fuel system pressure is now relieved.
   ⚠️Do not skip this step. Pressurized fuel can spray when lines are disconnected, creating fire hazard and risk of injury.
2. 2

   Access fuel pump module
   In the truck bed, locate the rectangular fuel pump access cover on the driver's side, forward of the rear axle. The cover is secured by 6-8 Phillips screws around the perimeter. Remove all screws and carefully lift the access cover. Set aside the rubber seal gasket for inspection (replace if damaged).
3. 3

   Clean tank surface
   Using a non-sparking brush and shop towels, thoroughly clean the area around the fuel pump module to prevent debris from falling into the fuel tank when the module is removed. Wipe clean the lock ring and all visible surfaces. Any dirt entering the tank can damage the new pump.
   ⚠Use only non-sparking tools near the open fuel tank. Even small sparks can ignite fuel vapors.
4. 4

   Disconnect electrical connector
   Locate the large gray electrical connector on top of the fuel pump module. Press the tab on the connector and pull straight up to disconnect. Inspect connector terminals for corrosion or damage. If connector is stuck, gently rock while pulling—do not force.
   ⚠Do not break the connector locking tab. Replacement connectors are expensive and require wire splicing.
5. 5

   Disconnect fuel supply and EVAP lines
   Identify the fuel supply line (larger diameter, typically 3/8-inch) and EVAP vent line (smaller, typically 1/4-inch) connected to the pump module. Using the appropriate size fuel line disconnect tool, push the tool into the quick-connect fitting while pulling the line straight out. Have shop towels ready to catch residual fuel (expect 1-2 ounces). Plug or cap the disconnected lines to prevent contamination.
   ⚠Residual fuel will drain from lines. Wear fuel-resistant gloves and have absorbent materials ready.
6. 6

   Remove fuel pump module lock ring
   Position the fuel pump lock ring tool J-45722 onto the lock ring tabs (8 tabs around perimeter). Using a long breaker bar or ratchet, rotate the lock ring counterclockwise to loosen. Initial break-free may require significant force. Once loosened, unscrew the lock ring completely by hand and remove. Note the orientation of the module before removal.
   ⚠️NEVER use a hammer and punch to loosen the lock ring. Impact tools near fuel vapors create serious fire risk.
   ⚠Lock ring may be very tight. Use steady pressure—do not use impact tools or excessive force that could damage tank threads.
   Torque spec

   Fuel Pump Module Lock Ring80 Nm (59 lb-ft)
7. 7

   Remove fuel pump module assembly
   Carefully tilt the fuel pump module toward the rear of the vehicle while lifting it out of the tank opening. The fuel level sender float arm extends downward and must clear the tank opening without bending. Continue tilting as you lift until the entire assembly is clear. Have a drain pan ready as fuel will drain from the module (approximately 1-2 cups). Place the old module in a suitable container.
   ⚠The fuel level sender float arm is fragile. Avoid bending or damaging the arm during removal or the fuel gauge will read incorrectly.
   ⚠Significant fuel will drain from the module. Use drain pan and have absorbent materials ready.
8. 8

   Inspect and clean tank opening
   Remove the old O-ring seal from the tank opening groove and discard. Inspect the tank opening for debris, corrosion, or damage. Clean the O-ring sealing surface with a lint-free cloth. Check that the tank opening threads are not damaged or crossed. Verify no debris fell into the tank during removal.
   ℹ️This is your only opportunity to inspect the tank interior. Use a flashlight to check for debris, rust, or contamination that could damage the new pump.
9. 9

   Prepare new fuel pump module
   Remove the new fuel pump module from packaging. Install the new O-ring seal onto the module (not in the tank groove—it sits on the module flange). Lightly lubricate the O-ring with clean gasoline to aid installation. Verify the fuel level sender float arm moves freely and is not bent. Compare the new module to the old one to confirm correct replacement.
   ⚠Do not use petroleum-based lubricants on O-rings. Use only clean gasoline or approved fuel system lubricant.
10. 10

    Install new fuel pump module
    Align the fuel pump module with the tank opening, noting the orientation marks or tabs that ensure correct positioning. Carefully tilt and lower the module into the tank, guiding the float arm through the opening without bending it. Once the module is fully seated with the O-ring compressed against the tank, verify it sits flat and even around the entire perimeter.
    ⚠Module must be oriented correctly or it will not seal properly and fuel gauge may not read accurately. Match alignment marks on module and tank.
11. 11

    Install and torque lock ring
    Place the lock ring over the fuel pump module, aligning it with the tank threads. Thread the lock ring clockwise by hand until it is finger-tight. Using the fuel pump lock ring tool J-45722 and torque wrench, tighten the lock ring to 80 Nm (59 lb-ft). Ensure even seating by checking that the gap between lock ring and tank is uniform around the entire circumference.
    ⚠Improper torque can cause fuel leaks. Use calibrated torque wrench and proper tool—do not estimate.
    Torque spec

    Fuel Pump Module Lock Ring80 Nm (59 lb-ft)
12. 12

    Reconnect fuel lines and electrical connector
    Install new O-rings on the fuel supply and EVAP line quick-connect fittings (if included with pump or purchased separately). Push each line straight onto the module fitting until you hear and feel a definite click. Pull back on each line to verify it is locked. Reconnect the electrical connector by pushing straight down until the locking tab clicks into place. Verify secure connection by gently pulling on connector.
13. 13

    Reinstall access cover and restore power
    Inspect the rubber access cover seal for damage and replace if necessary. Position the access cover over the opening with the seal in place. Install all Phillips screws and tighten to 4.0 Nm (3 lb-ft) in a criss-cross pattern to ensure even sealing. Reconnect the negative battery cable. Reinstall the fuel pump fuse.

Reassembly

1. Ensure all fuel line connections are secure and properly locked—pull test each connection
2. Verify electrical connector is fully seated and latched
3. Double-check that lock ring is torqued to specification and seated evenly
4. Confirm access cover is properly sealed to prevent water intrusion into fuel tank

Verification

• Turn ignition to ON position (do not start) for 2 seconds, then OFF. Repeat 3-4 times to prime fuel system. Listen for fuel pump activation (buzzing sound from tank area)
• Inspect all connections at the fuel pump module for fuel leaks while system is pressurized
• Start the engine and verify it runs smoothly without hesitation or fuel pressure warnings
• Check for fuel odor or visible leaks around access cover and all connections
• Verify fuel gauge reads correctly by comparing to known fuel level (may take a few minutes of driving to stabilize)
• Test drive vehicle and monitor for proper engine performance, fuel delivery, and absence of leaks
• After test drive, re-inspect all connections and access cover area for any signs of leakage
• Clear any diagnostic trouble codes that may have set during the fuel pressure relief procedure

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