High Pressure Fuel Pump

This procedure replaces the high-pressure fuel pump on the 3.5L EcoBoost engine, which is mounted on the engine and supplies fuel at high pressure to the direct injection system.

Warnings

Tools required

Parts

• High-pressure fuel pump assembly × 1 — Use OEM specification
• Fuel pump mounting seal/gasket × 1 — Usually included with pump
• Fuel line O-rings × 4 — Use OEM specification
• Shop towels × 1 — Generic

Preparation

1. Ensure engine is completely cold (minimum 2 hours after last operation)
2. Park vehicle on level ground, engage parking brake, and chock rear wheels
3. Disconnect negative battery cable and wait 10 minutes for system capacitors to discharge
4. Remove engine cover by pulling upward on front clips and lifting
5. Place fire extinguisher within easy reach of work area
6. Prepare clean workspace with drain pan and absorbent materials for fuel spillage
7. Verify replacement pump matches OEM specifications and includes new seal/gasket

Procedure

1. 1

   Relieve fuel system pressure
   Locate the fuel rail Schrader valve on the driver's side fuel rail. Attach fuel pressure gauge with drain hose routed into an approved fuel container. Slowly open the valve to bleed pressure until gauge reads zero. This may take 2-3 minutes. Close valve and remove gauge. Fuel will drain from the hose - capture all spillage.
   ⚠️Fuel will spray under high pressure if valve is opened too quickly. Open valve gradually and keep face and body clear of the valve.
2. 2

   Disconnect fuel supply line
   Locate the low-pressure fuel supply line connecting to the inlet side of the high-pressure pump (passenger side of engine valley). Use the appropriate fuel line disconnect tool to release the quick-connect fitting. Press tool onto fitting while pulling line away from pump. Expect residual fuel spillage - capture with towels and drain pan.
   ⚠Residual fuel under pressure may spray when disconnecting. Have towels ready and wear safety glasses.
3. 3

   Disconnect high-pressure fuel line
   Locate the high-pressure fuel line on the outlet side of the pump. This uses a threaded fitting. Using a flare nut wrench or line wrench, carefully loosen the fitting by turning counterclockwise. Support the pump body to prevent stress. Once loose, carefully unthread and remove line. Capture any fuel spillage. Inspect O-ring - it must be replaced.
   ⚠Do not use standard open-end wrenches on fuel line fittings as they can round off the soft metal. Use only flare nut or line wrenches.
4. 4

   Disconnect electrical connector
   Locate the electrical connector on top of the high-pressure fuel pump. Press the release tab and pull connector straight off the pump. Inspect connector pins for corrosion or damage. If connector is stuck, gently wiggle while pulling - do not force.
5. 5

   Remove vacuum line (if equipped)
   Some configurations have a vacuum reference line connected to the fuel pressure regulator on the pump. If present, squeeze the clamp tabs and slide clamp back, then pull vacuum hose off the nipple. If not present on your pump, proceed to next step.
6. 6

   Remove pump mounting bolts
   The high-pressure fuel pump is secured by three mounting bolts (typically 8mm or 10mm heads) arranged in a triangular pattern. Using a socket or wrench, remove all three bolts completely. Keep bolts organized as they may be different lengths depending on position. Note the orientation of any brackets or clips attached to the bolts.
   Torque spec

   Pump Mounting16 Nm (12 lb-ft)
7. 7

   Remove high-pressure fuel pump
   Carefully pull the pump assembly straight out from its mounting location on the engine. The pump drives off a camshaft lobe, so there will be a driven coupling that disengages. Pull firmly but steadily. Once free, tilt pump to drain any residual fuel into drain pan. Inspect the pump mounting surface on the engine for debris or damage.
   ⚠Do not rotate the pump while removing as this can damage the drive coupling or camshaft lobe.
8. 8

   Inspect and clean mounting surface
   Remove the old mounting gasket/seal from the engine mounting surface. Clean the surface thoroughly with a lint-free cloth - no gasket scraper needed as this is typically a rubber seal. Inspect the camshaft lobe through the opening for any unusual wear or damage. Verify the drive coupling area is clean and free of debris. Check that the new pump's drive coupling moves freely.
   ⚠Do not allow any debris to enter the engine through the pump mounting hole. Cover opening with clean shop towel if taking a break.
9. 9

   Install new fuel line O-rings
   Install new O-rings on both the high-pressure outlet fitting and low-pressure inlet fitting of the new pump. Lightly lubricate O-rings with clean engine oil or fresh gasoline - do not use petroleum jelly or grease. Ensure O-rings are seated properly in their grooves without twisting or pinching.
   ℹ️Old or improperly installed O-rings are a common cause of fuel leaks. Always use new O-rings and verify proper seating.
10. 10

    Install new high-pressure fuel pump
    Position the new gasket/seal on the pump or engine mounting surface per manufacturer instructions. Align the pump drive coupling with the camshaft lobe - you may need to rotate the coupling slightly to engage. Carefully push the pump into place, ensuring it seats fully against the mounting surface. The pump should sit flush with no gaps.
    ⚠Forcing the pump can damage the drive coupling or camshaft. If pump does not seat easily, remove and check coupling alignment.
11. 11

    Install pump mounting bolts
    Install all three mounting bolts finger-tight, ensuring any brackets or clips are positioned correctly. Tighten bolts in a crossing pattern (not sequentially around) to ensure even seating. Torque all mounting bolts to 16.0 Nm (12.0 lb-ft) using the crossing pattern. Verify pump is seated evenly with no gaps.
    Torque spec

    Pump Mounting16 Nm (12 lb-ft)
12. 12

    Connect high-pressure fuel line
    Thread the high-pressure fuel line onto the pump outlet fitting by hand to avoid cross-threading. Once hand-tight, use a flare nut wrench to tighten to 31.0 Nm (23.0 lb-ft). Support the pump body while tightening to prevent stress on mounting bolts. Do not over-tighten as this can damage the fitting or O-ring.
    Torque spec

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

    Connect low-pressure fuel supply line
    Push the low-pressure fuel supply line quick-connect fitting straight onto the pump inlet until you hear and feel a positive click. Verify connection by pulling firmly on the line - it should not release. Ensure the fitting safety clip (if equipped) is properly engaged.
14. 14

    Reconnect electrical and vacuum connections
    Push the electrical connector onto the pump until it clicks into place. Verify the locking tab is fully engaged. If vacuum line was present, reconnect it to the pressure regulator nipple and slide the clamp into position. Inspect all connections visually.
15. 15

    Prime fuel system and check for leaks
    Reconnect the negative battery cable. Turn ignition key to ON position (do not start) for 5 seconds, then OFF. Repeat this cycle 5-6 times to allow fuel pump to prime the system. Carefully inspect all fuel connections for any signs of leakage. Look for wet spots, drips, or fuel odor. If any leaks are present, relieve pressure and correct before proceeding.
    ⚠️Do not start engine if any fuel leaks are visible. Even small leaks can cause fire when engine heat is applied.

Reassembly

1. Reinstall engine cover by aligning rear tabs first, then pressing down on front clips until they snap into place
2. Double-check that all tools have been removed from engine bay
3. Verify no fuel-soaked towels or materials are left in engine compartment

Verification

• Start engine and allow to idle for 2-3 minutes while monitoring fuel system connections for leaks
• With engine running, visually inspect high-pressure pump and all connections for any signs of fuel seepage or wetness
• Check for unusual noises from pump area - high-pressure pump should operate quietly
• Perform a test drive and verify normal engine performance with no hesitation, rough running, or fuel pressure-related codes
• After test drive, re-inspect all fuel connections with engine hot for any signs of leakage
• Use a scan tool to verify fuel pressure readings are within specification (typically 350-2,900 PSI depending on load)
• Monitor for fuel odor in cabin or engine bay over the next few days of operation

More procedures for this vehicle