High Pressure Fuel Pump

Replace the high-pressure fuel pump on the 3.5L EcoBoost engine, which is mounted on the engine block and supplies pressurized fuel to the direct injection system.

Warnings

Tools required

Parts

• High-pressure fuel pump (HPFP) × 1 — Motorcraft CM-5316 or equivalent
• High-pressure fuel pump seal/gasket × 1 — Use OEM specification
• Fuel line O-rings × 4 — Use OEM specification
• Fuel system cleaner spray × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Ensure engine is completely cold before beginning work
3. Place wheel chocks at rear wheels
4. Disconnect negative battery cable and wait 10 minutes to allow fuel pump control module to power down
5. Remove engine cover by lifting straight up from grommets
6. Have adequate lighting available as HPFP is located deep in valley between cylinder banks
7. Prepare clean workspace for parts and have multiple clean shop towels ready
8. Review fuel line routing and take photos for reference during 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 to the valve. Slowly open the valve to release pressure into a suitable container. Monitor gauge until pressure reads zero PSI. Close valve and remove gauge. Wrap shop towels around any fuel line connections you will be working with to catch residual fuel.
2. 2

   Remove air intake components
   Remove the air intake tube from the throttle body to the air filter housing. Disconnect the PCV hose and any vacuum lines attached to the intake tube. Remove the upper air intake resonator if it obstructs access. Set components aside in clean area.
3. 3

   Access the high-pressure fuel pump
   The HPFP is located in the valley between the cylinder banks, driven by the camshaft. You may need to remove ignition coils and move wiring harnesses aside for better access. On some model years, removing the charge air cooler tube provides better access. Label all electrical connectors before disconnecting.
4. 4

   Disconnect electrical connector
   Locate the electrical connector on the HPFP. Press the locking tab and carefully disconnect the connector. Inspect connector pins for corrosion or damage. Move connector away from work area to prevent contamination.
5. 5

   Disconnect low-pressure fuel supply line
   Identify the low-pressure fuel inlet line coming from the fuel rail/tank. Use the appropriate fuel line disconnect tool for the quick-connect fitting. Have shop towels ready as fuel will drain from the line. Cap or plug the line to prevent contamination. Inspect the O-ring on the fitting and plan to replace during reassembly.
6. 6

   Disconnect high-pressure fuel outlet line
   Using a flare-nut wrench or appropriate tool, carefully loosen the high-pressure fuel line fitting at the pump outlet. This is a metal hard line with a threaded fitting. Hold the pump body steady while loosening to prevent damage. Once loose, completely remove the fitting and carefully move the fuel line aside. Some residual fuel will drain out.
   Torque spec

   Fuel Line Fittings25 Nm (18 lb-ft)
7. 7

   Remove pump mounting bolts
   Locate the three mounting bolts securing the HPFP to the engine block. These are typically 8mm or 10mm hex bolts. Remove the bolts in a crisscross pattern, loosening gradually to prevent binding. Keep bolts organized as they may be different lengths. Note the position of any brackets or clips attached to the pump.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
8. 8

   Remove high-pressure fuel pump
   Carefully pull the HPFP straight out from the engine block. The pump is driven by a lobe on the camshaft, so it may require slight wiggling while pulling. Do not pry against the pump body. Once removed, keep the pump upright and place in a safe location. Immediately inspect the mounting bore for debris or damage.
9. 9

   Clean mounting surface and inspect components
   Use clean shop towels to wipe the mounting surface on the engine block. Do NOT allow any debris to fall into the camshaft bore or engine valley. Inspect the camshaft drive lobe for wear or damage. Check that the roller follower on the old pump moves freely. Use compressed air to blow away any debris from the mounting area, being careful to shield surrounding components.
10. 10

    Prepare new high-pressure fuel pump
    Remove the new HPFP from packaging. Install the new seal/gasket onto the pump body, ensuring it seats properly in the groove. Lubricate the seal with a small amount of clean engine oil. Replace all O-rings on fuel line connections with new parts from the kit, lubricating each with clean engine oil. Verify the roller follower on the new pump moves freely.
11. 11

    Install new high-pressure fuel pump
    Carefully align the new pump with the mounting bore, ensuring the roller follower will contact the camshaft lobe properly. The pump will only install in one orientation. Push the pump in gently while rotating the engine slightly by hand (using a socket on the crankshaft bolt) if needed to align the roller with the cam lobe. Push until the mounting flange contacts the engine block.
12. 12

    Install mounting bolts
    Install all three mounting bolts finger-tight first, ensuring the pump seats evenly against the block. Tighten the bolts in a crisscross pattern to the specified torque of 31 Nm (23 lb-ft). Do not over-torque as this can damage the pump housing or strip threads in the aluminum block.
    Torque spec

    Mounting Bolts31 Nm (23 lb-ft)
13. 13

    Reconnect high-pressure fuel line
    Inspect the high-pressure fuel line fitting threads and sealing surface. Install the fuel line to the pump outlet, threading by hand first to ensure proper alignment. Tighten to 31 Nm (23 lb-ft) using a torque wrench and flare-nut wrench. Hold the pump body steady to prevent twisting.
    Torque spec

    Fuel Line Fittings25 Nm (18 lb-ft)
14. 14

    Reconnect low-pressure fuel supply line
    Install a new O-ring on the quick-connect fitting if not already done. Push the fuel supply line firmly onto the pump inlet until you hear and feel a distinct click. Tug gently on the line to verify it is locked in place. The connection should be secure with no movement.
15. 15

    Reconnect electrical connector and reinstall components
    Reconnect the electrical connector to the HPFP, ensuring it clicks into place securely. Reinstall any ignition coils, wiring harnesses, or charge air cooler tubes that were removed. Reinstall the air intake components in reverse order of removal. Ensure all vacuum lines and PCV connections are secure. Reinstall the engine cover.

Reassembly

1. Double-check all fuel line connections are secure and properly seated
2. Verify electrical connector is fully locked in place
3. Ensure no tools or parts are left in the engine valley
4. Reconnect negative battery cable
5. Do not start engine yet - proceed to verification steps

Verification

• Turn ignition key to ON position (do not start) for 5 seconds, then OFF. Repeat 3 times to allow fuel pump to prime the system
• Visually inspect all fuel connections for leaks during priming cycles
• After priming, start the engine and let it idle. Immediately check all fuel connections for any signs of fuel seepage or leakage
• With engine running, use a flashlight to carefully inspect the HPFP and all connections. Look for fuel wetness, drips, or spray
• Listen for unusual noises from the HPFP area that could indicate improper installation or air in the system
• Allow engine to reach operating temperature and verify smooth idle and no fuel odor in cabin or engine bay
• Check for diagnostic trouble codes using a scan tool. Address any fuel pressure-related codes immediately
• Perform a test drive to verify proper acceleration and no hesitation under load
• After test drive, allow engine to cool and recheck all connections for any fuel leaks one final time
• If any fuel leaks are detected at any point, immediately shut down engine, relieve pressure, and correct the issue before operating vehicle

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