This procedure covers removal and installation of the fuel rail assembly on a 2015-2020 Ford F-150 with the 3.5L EcoBoost V6 engine, including fuel system depressurization and injector connection.

Warnings

Tools required

Parts

• Fuel rail assembly × 1 — Use OEM specification
• Fuel injector O-ring kit × 1 — 6 upper and 6 lower O-rings
• Fuel line O-rings × 2 — Use OEM specification

Preparation

1. Ensure engine is completely cool to the touch
2. Park vehicle on level ground and engage parking brake
3. Disconnect negative battery cable and wait 2 minutes for system capacitors to discharge
4. Remove engine cover by pulling upward on cover - it is retained by grommets
5. Place shop towels and drain pan beneath work area to catch residual fuel
6. Label all electrical connectors and vacuum lines with tape or wire ties for correct reassembly

Procedure

1. 1

   Relieve fuel system pressure
   Locate the fuel rail Schrader valve on the driver side fuel rail. Attach the fuel pressure gauge with drain hose into a fuel-safe container. Slowly open the valve to bleed fuel pressure until gauge reads zero. Close valve and remove gauge. Wipe up any spilled fuel immediately.
   ⚠️Expect fuel spray when opening Schrader valve. Keep face and ignition sources away from valve.
2. 2

   Disconnect fuel supply line
   Locate the fuel supply line connection at the passenger side of the fuel rail. Use the appropriate fuel line disconnect tool to depress the release tabs while pulling the line straight off the rail. Inspect the connection for debris and clean if necessary. Note the installed position of any retaining clips.
   ⚠Residual fuel will drain from the line. Have shop towels ready to catch spillage.
3. 3

   Disconnect fuel injector electrical connectors
   Disconnect all six fuel injector electrical connectors by pressing the release tab on each connector and pulling straight up. On the 3.5L EcoBoost, these are the port injector connectors located on top of the intake manifold. Keep connectors away from the work area to prevent damage.
4. 4

   Remove vacuum lines and brackets
   Disconnect any vacuum lines attached to or crossing the fuel rail. On the EcoBoost, this typically includes the PCV hose connections and brake booster vacuum line if it interferes. Remove any wiring harness brackets or clips attached to the fuel rail mounting area. Note their positions for reinstallation.
   ℹ️Take photos of vacuum line routing before disconnection to ensure correct reassembly.
   Torque spec

   Bracket Bolts23 Nm (17 lb-ft)
5. 5

   Remove fuel rail mounting bolts
   Locate the four fuel rail mounting bolts (two per rail on the 3.5L EcoBoost). Using an 8mm socket, remove all four bolts. Keep bolts organized as they must be reinstalled in the same locations. The fuel rail may now be loose but injectors are still seated in the intake manifold.
   Torque spec

   Fuel Rail Bolts12 Nm (9 lb-ft)
6. 6

   Remove fuel rail and injectors as assembly
   Grasp the fuel rail firmly with both hands. Apply steady upward pressure while gently rocking the rail side to side to break the injector O-ring seals. Pull the entire fuel rail and injector assembly straight up and out of the intake manifold. Residual fuel will drain - have towels ready. Place the assembly on a clean work surface.
   ⚠Do not pry against the fuel rail or injectors as this can cause damage. Use only hand pressure to remove.
7. 7

   Inspect and clean injector bores
   Inspect the six injector ports in the intake manifold for debris, carbon buildup, or damaged O-ring seats. Use compressed air to blow out any debris. Wipe the port edges clean with a lint-free shop towel. Inspect the fuel rail mounting surfaces and clean thoroughly. Do not allow debris to enter the intake ports.
   ⚠Cover open injector ports with clean shop towels to prevent foreign material from entering the intake manifold.
8. 8

   Prepare new fuel rail assembly
   If installing a new fuel rail assembly, transfer any brackets or fittings from the old rail as needed. Install new O-rings on all fuel line fittings, lubricating them lightly with clean engine oil. If reusing injectors, install new upper and lower O-rings on each injector, also lubricated with clean engine oil. Ensure O-rings are seated properly in their grooves without twists.
   ℹ️Never reuse fuel system O-rings. Always install new O-rings lubricated with clean engine oil only - do not use petroleum jelly or other lubricants.
   Torque spec

   Fuel Line Fittings25 Nm (18 lb-ft)
9. 9

   Install fuel rail and injector assembly
   Remove protective covers from intake manifold ports. Align all six injectors with their corresponding bores. Press the fuel rail assembly straight down with firm, even pressure until all injectors are fully seated. The rail should sit flush against the mounting surface. Do not allow the rail to cock to one side during installation.
10. 10

    Install fuel rail mounting bolts
    Install all four fuel rail mounting bolts finger-tight first, ensuring the rail is properly positioned. Using a torque wrench and 8mm socket, tighten the bolts in a criss-cross pattern to the specified torque. Verify the fuel rail sits evenly and does not rock.
    Torque spec

    Fuel Rail Bolts12 Nm (9 lb-ft)
11. 11

    Reconnect fuel supply line and components
    Push the fuel supply line straight onto the fuel rail fitting until you hear and feel a distinct click indicating the connection is locked. Gently tug the line to verify it is secure. Reinstall any brackets removed earlier, torquing bracket bolts to specification. Reconnect all vacuum lines in their original positions.
    ℹ️The fuel line must click into place. If no click is heard, the connection is not secure and will leak.
    Torque spec

    Bracket Bolts23 Nm (17 lb-ft)
12. 12

    Reconnect electrical connectors
    Reconnect all six fuel injector electrical connectors by pushing straight down until each clicks into place. Verify each connection is secure by gently pulling on the connector body. Ensure no wiring is pinched or routed where it could contact hot exhaust components.
13. 13

    Pressure test fuel system
    Reconnect the negative battery cable. Turn the ignition key to the ON position without starting the engine. Listen for the fuel pump to run for 2-3 seconds to prime the system. Cycle the key OFF and ON three times, waiting 5 seconds between cycles. Carefully inspect all fuel connections, the fuel rail, and injector seals for any signs of fuel leakage. Wipe the area dry and observe for wetness.
    ⚠️Any fuel leak must be corrected immediately before starting the engine. Do not attempt to start the engine if fuel leakage is present.

Reassembly

1. Reinstall the engine cover by aligning the grommets and pressing down firmly until seated
2. Double-check that all electrical connectors are fully seated and locked
3. Verify all tools and shop towels have been removed from the engine bay
4. Clean up any spilled fuel from surrounding components with shop towels

Verification

• Start the engine and allow it to idle. Listen for smooth operation and verify there are no fuel odors
• Inspect all fuel connections and the fuel rail area for leaks while the engine is running
• Check for diagnostic trouble codes using a scan tool - there should be no fuel system related codes
• Rev the engine to 2000 RPM and verify smooth acceleration with no misfires or hesitation
• Allow engine to reach normal operating temperature and recheck for any fuel leaks
• Test drive the vehicle to verify normal performance and fuel delivery under load

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