Fuel Injectors - All

This procedure covers the complete replacement of all eight fuel injectors on the 5.0L Coyote V8 engine, including fuel system depressurization, fuel rail removal, and injector replacement.

Warnings

Tools required

Parts

• Fuel injector × 8 — Motorcraft CM-5243 or equivalent for 5.0L Coyote
• Fuel injector O-ring kit × 1 — Upper and lower O-rings for 8 injectors
• Fuel rail O-rings × 2 — Use OEM specification
• Intake manifold gasket set × 1 — Use OEM specification if disturbed

Preparation

1. Park vehicle on level surface and ensure engine is completely cool
2. Disconnect negative battery terminal and wait 5 minutes for system capacitors to discharge
3. Remove engine cover by pulling upward on four retention points
4. Place absorbent shop towels around fuel lines and work area
5. Have fire extinguisher rated for fuel fires readily accessible

Procedure

1. 1

   Relieve fuel system pressure
   Locate the fuel pressure test port on the fuel rail (driver side, rear of rail). Remove the cap from the Schrader valve. Attach a fuel pressure gauge with drain hose into a fuel-safe container. Slowly open the valve to bleed system pressure until gauge reads zero. Close valve and remove gauge. Wipe up any spilled fuel immediately.
   ⚠️Fuel will spray from test port under pressure. Keep face and body clear of test port and direct hose into drain pan.
2. 2

   Disconnect fuel supply line
   Locate the fuel supply line connection at the front passenger side of the fuel rail. Use the appropriate fuel line disconnect tool to release the spring clip retainer. Pull the line straight off the fuel rail. Cap or plug the line to prevent contamination. Inspect the O-ring in the fuel rail connection and discard if damaged.
   Torque spec

   Fuel Line Fittings25 Nm (18 lb-ft)
3. 3

   Disconnect electrical connectors
   Disconnect the fuel injector electrical harness connectors from all eight injectors. Press the locking tab and pull straight up on each connector. On the driver side, you may need to remove the ignition coil harness bracket for better access. Label connectors if necessary to ensure correct reassembly order (cylinder 1-8).
   ⚠Do not pull on wires. Always grasp the connector body to prevent damage to terminals.
4. 4

   Remove vacuum lines and accessories
   Disconnect the PCV hose from the passenger side valve cover. Disconnect the brake booster vacuum hose from the rear of the intake manifold. Remove any wire harness clips or brackets attached to the fuel rails. On some models, disconnect the fuel pressure sensor electrical connector on the driver side fuel rail.
5. 5

   Remove fuel rail mounting bolts
   Locate the four fuel rail mounting bolts (two per rail). On the driver side rail, remove the two bolts securing the rail to the intake manifold. On the passenger side rail, remove the two bolts. Keep bolts organized as they will be reused. Note the location of any harness brackets or spacers under bolt heads.
   Torque spec

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

   Remove fuel rails with injectors
   Carefully pull upward on each fuel rail to dislodge the injectors from the intake manifold bores. The rails should lift off with all injectors still attached. Work the rails back and forth gently if they resist - do not pry. Once free, carefully maneuver the rail assemblies out of the engine valley. Place rails on clean shop towels on a workbench.
   ⚠Fuel will drain from injectors and rails. Keep drain pan positioned to catch residual fuel.
   ℹ️Injector tips are delicate. Avoid dropping or hitting injectors against hard surfaces.
7. 7

   Remove old injectors from fuel rails
   On the workbench, release the injector retaining clips from each fuel rail position. Use a small flathead screwdriver to pry the metal clip upward and off. Gently pull each injector straight out of the fuel rail. If injectors are stuck, use an injector puller tool or carefully wiggle while pulling. Remove and discard all old O-rings from both the fuel rail seats and injector tips.
8. 8

   Clean intake manifold injector bores
   Inspect each of the eight injector bores in the intake manifold for debris, carbon buildup, or old O-ring material. Use a clean shop towel to wipe out each bore. A vacuum can be used to remove loose debris. DO NOT allow any debris to fall into the intake ports. Stuff clean shop towels into open ports if necessary to prevent contamination.
   ⚠Any debris entering the combustion chamber can cause engine damage. Keep bores and ports scrupulously clean.
9. 9

   Install new O-rings on injectors
   Lightly lubricate new O-rings with clean engine oil or gasoline. Install the upper O-ring into the groove near the top of each new injector (fuel rail end). Install the lower O-ring into the groove near the spray tip (intake manifold end). Ensure O-rings are seated properly in their grooves with no twisting or pinching.
   ℹ️Never reuse old O-rings. Always use new O-rings supplied with injectors or from injector O-ring kit.
10. 10

    Install injectors into fuel rails
    Push each new fuel injector straight into its corresponding position in the fuel rail until fully seated. The injector should slide in smoothly with light pressure. Rotate injector to align the electrical connector tab to the correct orientation (pointing outward from rail). Install the retaining clip over each injector, ensuring it snaps into place and secures the injector.
11. 11

    Install new fuel rail O-rings
    Install new O-rings onto the fuel rail supply connection points where the fuel line attaches. Lightly lubricate with clean gasoline. Inspect the fuel rail mounting points and ensure they are clean and free of damage.
    Torque spec

    Fuel Line Fittings25 Nm (18 lb-ft)
12. 12

    Install fuel rails into engine
    Carefully position each fuel rail assembly over the intake manifold with all eight injectors aligned with their respective bores. Press down firmly and evenly on the fuel rail to seat all injectors into the manifold bores. All injectors must be fully seated before installing mounting bolts. Verify injectors are flush with the intake manifold surface.
    ⚠Do not force rails into place. If resistance is felt, remove rails and check for misalignment or debris.
13. 13

    Install fuel rail mounting bolts
    Install the four fuel rail mounting bolts (two per rail) finger-tight. Reinstall any harness brackets or spacers in their original positions. Using a torque wrench, tighten all four bolts to specification in a cross-pattern (alternate between driver and passenger side). Verify rails are secure and injectors remain fully seated.
    Torque spec

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

    Reconnect fuel supply line
    Push the fuel supply line straight onto the fuel rail connection until it clicks into place. Tug on the line to verify it is locked. Ensure the spring clip retainer is fully engaged.
    ℹ️Connection must click audibly to confirm proper engagement of internal locking mechanism.
    Torque spec

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

    Reconnect electrical and vacuum connections
    Reconnect all eight fuel injector electrical connectors, ensuring each clicks into place. Reconnect the PCV hose to the passenger valve cover. Reconnect the brake booster vacuum line. Reconnect the fuel pressure sensor if equipped. Reinstall any wire harness brackets or clips. Reconnect the negative battery terminal.

Reassembly

1. Reinstall engine cover by pressing down on four retention points until all clips engage
2. Double-check all electrical connections are secure and properly seated
3. Verify no tools or shop towels remain in engine compartment

Verification

• Turn ignition key to ON position (do not start) for 5 seconds, then OFF. Repeat 3 times to prime fuel system. Check for fuel leaks around fuel rail connections and all injector seals
• Start engine and let idle. Listen for smooth operation and check for any fuel odor or visible leaks
• Check for diagnostic trouble codes using scan tool. Clear any fuel trim adaptation codes if necessary
• Road test vehicle under various load conditions to verify proper injector operation and engine performance
• Recheck for leaks after test drive with engine at operating temperature

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