Fuel Injector Cleaning

This procedure covers cleaning the fuel injectors on a 2015-2020 Ford F-150 with the 3.5L EcoBoost V6 engine using a professional fuel injector cleaning kit without removing the injectors from the fuel rail.

Warnings

Tools required

Parts

• Fuel line O-rings × 2 — Use OEM specification
• Engine cover grommet set (if damaged) × 1 — Use OEM specification
• Fuel injector cleaning solution × 1 — BG 44K or equivalent

Preparation

1. Park vehicle on level surface and apply parking brake
2. Ensure engine is completely cold to the touch (wait at least 2 hours after operation)
3. Disconnect negative battery terminal and wait 2 minutes for system capacitors to discharge
4. Have fire extinguisher readily accessible in work area
5. Cover fenders with protective blankets to prevent damage

Procedure

1. 1

   Remove engine cover
   Grasp the engine cover firmly at the front and rear sections. Pull upward with steady force to disengage the rubber grommets from the mounting posts. The cover is held by friction fit grommets only. Inspect grommets for damage and replace if cracked or torn.
2. 2

   Relieve fuel system pressure
   Locate the fuel pump relay in the power distribution box (passenger side engine compartment). Remove the fuel pump relay (consult owner's manual for exact location). Attempt to start the engine and let it run until it stalls from fuel starvation. Crank the engine for an additional 5 seconds to ensure complete pressure relief. Turn ignition off and reinstall fuel pump relay.
   ⚠️Even after relieving pressure, residual fuel will be present in lines. Have shop towels ready to catch fuel.
3. 3

   Disconnect fuel supply line
   Locate the fuel supply line connection at the fuel rail on the driver's side of the engine. Place shop towels around the connection area to catch residual fuel. Using the appropriate fuel line disconnect tool, press the tool into the quick-connect fitting and pull the fuel line straight away from the fuel rail. Cap the fuel line with a clean plug to prevent contamination.
   ⚠Expect approximately 2-4 oz of fuel to drain from the disconnected line. Dispose of fuel-soaked towels properly.
4. 4

   Disconnect electrical connectors from injectors
   Each of the six port fuel injectors has an electrical connector on top. Press the locking tab on each connector and pull straight up to disconnect. Keep track of connector positions if wire lengths vary. Use compressed air to clean any debris from the injector connector area before disconnecting.
5. 5

   Remove vacuum lines and brackets
   Disconnect any vacuum lines or wiring harness brackets attached to or crossing over the fuel rail. On the 3.5L EcoBoost, pay special attention to the brake booster vacuum line and PCV system connections near the fuel rail. Label connections if necessary for proper reinstallation.
6. 6

   Remove fuel rail mounting bolts
   Locate the four fuel rail mounting bolts (two per bank on the 3.5L V6). Using a 8mm socket, remove all four bolts. Keep bolts organized as they will be reinstalled to the specified torque. Note the location of any ground straps or brackets under the bolt heads.
   Torque spec

   Fuel Rail Bolts12 Nm (9 lb-ft)
7. 7

   Carefully lift fuel rail assembly
   Grasp the fuel rail firmly with both hands. Pull upward with steady, even pressure to disengage all six injectors from the intake manifold ports simultaneously. The injectors are held by O-rings and may require moderate force. Rock the rail gently side-to-side if needed, but do not pry against injectors. Once free, lift the entire fuel rail and injector assembly away and set on clean shop towels.
   ⚠Do not allow injectors to hang by electrical connectors or fuel lines. Support the entire assembly weight.
8. 8

   Connect fuel injector cleaning equipment
   Following the cleaning kit manufacturer's instructions, connect the cleaning canister to the fuel rail inlet where the supply line was removed. Ensure the adapter fitting is secure and compatible with the Ford fuel rail connection. Fill the cleaning canister with the recommended amount of fuel injector cleaning solution (typically 12-16 oz).
   ℹ️Use only professional-grade cleaning solutions designed for port fuel injectors. Do not use cleaners intended for diesel or direct injection systems.
9. 9

   Pressurize cleaning system and run cleaning cycle
   Pressurize the cleaning canister to 40-45 PSI using shop air or the kit's manual pump. Reconnect the negative battery terminal temporarily. Turn the ignition to ON position (do not start) to power the injectors. Activate the cleaning cycle per kit instructions, which typically pulses injectors open for 15-30 second intervals. Monitor canister pressure and solution level. Continue until all solution is consumed or per kit instructions (usually 15-20 minutes total runtime).
   ⚠Do not exceed 50 PSI in the cleaning system. Excessive pressure can damage injector seals.
10. 10

    Disconnect cleaning equipment and inspect injectors
    Turn ignition off and disconnect battery negative terminal. Depressurize the cleaning canister completely before disconnecting. Remove cleaning equipment from fuel rail. Inspect each injector tip for carbon buildup or damage. Spray tips should show uniform circular patterns. Check injector O-rings for swelling, cracking, or damage.
11. 11

    Clean intake manifold ports
    With injectors removed, inspect the six intake manifold injector ports. Use compressed air to blow out any debris or carbon deposits. Wipe the sealing surfaces clean with a lint-free cloth. Do not allow debris to fall into the intake runners. Verify O-ring sealing surfaces are smooth and undamaged.
12. 12

    Install new fuel line O-rings
    Remove old O-rings from the fuel rail inlet connection and any other disturbed fuel line connections. Lightly lubricate new O-rings with clean engine oil or fuel. Install new O-rings into the fuel rail grooves, ensuring they are seated properly without twisting or pinching.
    Torque spec

    Fuel Line Fittings25 Nm (18 lb-ft)
13. 13

    Reinstall fuel rail assembly
    Carefully align all six injectors with their corresponding intake manifold ports. Ensure injectors are rotated to the correct orientation for electrical connector access. Press down firmly and evenly on the fuel rail until all injectors are fully seated in their ports. The rail should sit flush against the mounting bosses. Install the four fuel rail mounting bolts hand-tight, then torque to specification in a cross-pattern.
    ⚠Verify all injector O-rings remain in place during installation. Pinched or displaced O-rings will cause fuel leaks.
    Torque spec

    Fuel Rail Bolts12 Nm (9 lb-ft)
14. 14

    Reconnect all connections
    Reconnect all six injector electrical connectors, pressing until the locking tabs click. Reinstall any vacuum lines, wiring harness brackets, and ground straps removed earlier. Reconnect the fuel supply line to the fuel rail, pushing until the quick-connect fitting clicks and locks. Tug gently on the line to verify secure connection.
    Torque spec

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

    Check for fuel leaks and reinstall engine cover
    Reconnect the negative battery terminal. Turn the ignition to ON position (without starting) for 5 seconds, then OFF. Repeat this cycle 3-4 times to prime the fuel system. Inspect all fuel connections for leaks, particularly at the fuel rail inlet and injector O-rings. Once verified leak-free, start the engine and check again while running. Allow engine to idle for 2-3 minutes. If no leaks are present, shut off engine and reinstall the engine cover by aligning grommets with mounting posts and pressing down firmly.
    ⚠️Any fuel leak must be corrected immediately. Do not operate vehicle with fuel leaks present.

Reassembly

1. Torque all fuel rail bolts to specification in cross-pattern to ensure even injector seating
2. Verify all electrical connectors are fully seated and locked before starting engine
3. Double-check fuel line quick-connect fittings are fully engaged and locked
4. Ensure engine cover grommets are properly seated on all mounting posts

Verification

• Start engine and verify smooth idle with no misfires or rough running
• Check for fuel odor or visible leaks around fuel rail, injectors, and supply line connection
• Use scan tool to verify no fuel system fault codes are present
• Test drive vehicle to confirm improved throttle response and acceleration
• Monitor fuel trim values with scan tool - long-term fuel trims should be between -10% and +10% after cleaning
• Recheck all fuel connections after first drive cycle and again after 50-100 miles

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