This procedure covers the removal and replacement of the fuel rail assembly on the 3.5L EcoBoost V6 engine, including depressurizing the fuel system and replacing fuel rail components.

Warnings

Tools required

Parts

• Fuel rail assembly × 1 — Use OEM specification
• Fuel injector O-rings (upper and lower) × 6 — Use OEM specification
• Fuel line O-rings × 2 — Use OEM specification
• Intake manifold gasket set (if damaged) × 1 — Use OEM specification

Preparation

1. Ensure engine is completely cool
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery cable and wait 5 minutes for system capacitors to discharge
4. Place fire extinguisher nearby as safety precaution
5. Prepare clean workspace and have drip pan ready for fuel spillage

Procedure

1. 1

   Relieve fuel system pressure
   Locate the fuel pressure relief valve on the fuel rail (driver side, under engine cover). Attach fuel pressure gauge with relief valve to the Schrader valve. Slowly open the relief valve and drain fuel into approved container until pressure reads zero. Remove gauge and replace protective cap on Schrader valve.
2. 2

   Remove engine cover
   Remove the plastic engine cover by pulling upward on the front edge to release the grommets. The cover is held by four rubber grommets and does not require tools. Set cover aside in clean area.
3. 3

   Disconnect electrical connectors
   Disconnect the electrical connector from each of the six fuel injectors by pressing the release tab and pulling straight up. Also disconnect the fuel pressure sensor connector on the driver side fuel rail. Mark or photograph connector positions for proper reassembly.
4. 4

   Remove air intake components
   Disconnect the air intake tube from the throttle body. Loosen hose clamps and remove the intake tube assembly to gain access to the fuel rail. On 4WD models, you may need to remove additional brackets for clearance.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
5. 5

   Disconnect fuel supply line
   Using appropriate fuel line disconnect tool, release the fuel supply line from the fuel rail at the driver side connection point. Push the disconnect tool into the fitting and pull the line straight back. Have shop towels ready to catch residual fuel. Inspect the O-rings in the fitting and note their condition.
6. 6

   Disconnect fuel return and crossover lines
   Disconnect the fuel return line on the passenger side using the fuel line disconnect tool. Also disconnect the fuel rail crossover line that connects the driver and passenger side rails. Cap or plug all open fuel line ends immediately to prevent contamination.
7. 7

   Remove vacuum line and brackets
   Disconnect the vacuum line from the fuel pressure regulator if equipped. Remove any bracket bolts that secure the fuel rail to the intake manifold or engine. The 3.5L EcoBoost typically has two brackets securing the fuel rails.
   Torque spec

   Bracket Bolts23 Nm (17 lb-ft)
8. 8

   Remove fuel rail mounting bolts
   Remove the four fuel rail mounting bolts (two per rail) using an 8mm socket. These bolts are located at the ends of each fuel rail. Keep bolts organized as they may have washers or specific positioning requirements. Do not pry on the fuel rail yet.
   Torque spec

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

   Remove fuel rail assembly
   Carefully work the fuel rail assembly upward to extract the fuel injectors from the intake manifold. Apply even upward pressure on both rails simultaneously. The injectors will release from the intake with moderate force. Once free, lift the entire fuel rail assembly with injectors attached away from the engine. Use shop towels to catch any residual fuel.
10. 10

    Inspect and clean injector bores
    Inspect the intake manifold injector bores for any debris, damaged O-rings, or carbon buildup. Use compressed air to blow out any debris. Check that the lower O-ring seats in the manifold are clean and undamaged. Do not allow any foreign material to fall into the intake ports.
11. 11

    Prepare new fuel rail assembly
    If installing new fuel rail, transfer fuel injectors if reusing them, ensuring new upper and lower O-rings are installed on each injector. Lubricate all new O-rings with clean engine oil before installation. Install new O-rings on all fuel line fittings. Verify fuel pressure sensor and all fittings are properly tightened on new rail.
12. 12

    Install fuel rail assembly
    Carefully align all six fuel injectors with their respective bores in the intake manifold. Press the fuel rail assembly downward with even pressure on both rails until all injectors are fully seated. The rails should sit flush against the mounting surfaces. Do not force or cock the assembly at an angle.
13. 13

    Install fuel rail bolts and brackets
    Install the four fuel rail mounting bolts and tighten to specification using a torque wrench. Tighten in a cross pattern to ensure even seating. Reinstall any brackets that were removed and torque bracket bolts to specification.
    Torque spec

    Fuel Rail Bolts12 Nm (9 lb-ft)

    Bracket Bolts23 Nm (17 lb-ft)
14. 14

    Reconnect fuel lines
    Reconnect the fuel supply line, return line, and crossover line to the fuel rail. Push each line firmly until you hear or feel a positive click indicating the connection is locked. Gently pull on each line to verify secure connection. Torque any threaded fuel fittings to specification.
    Torque spec

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

    Reconnect electrical and reinstall components
    Reconnect all six fuel injector electrical connectors and the fuel pressure sensor connector. Ensure each connector clicks into place. Reinstall the air intake tube and tighten hose clamps to specification. Reinstall the engine cover by aligning grommets with posts and pressing firmly until seated.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)

Reassembly

1. Double-check all fuel line connections are fully seated and locked
2. Verify all electrical connectors are properly attached with secure clips
3. Ensure no tools or shop towels are left in engine compartment

Verification

• Reconnect negative battery cable
• Turn ignition to ON position (do not start) for 5 seconds, then OFF. Repeat 3-4 times to prime fuel system and pressurize fuel rail
• Inspect all fuel connections for leaks while system is pressurized
• Start engine and allow to idle. Check for fuel leaks, unusual noises, or rough idle
• Check for diagnostic trouble codes related to fuel system or injectors
• Test drive vehicle and verify normal acceleration and no hesitation under load
• Recheck all connections after test drive for any signs of fuel seepage

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