Fuel Line - High Pressure

This procedure replaces the high-pressure fuel line between the fuel pump and fuel rail on a 2015 Kia Forte 1.8L I4, requiring fuel system depressurization and proper torque specifications to prevent fuel leaks.

Warnings

Tools required

Parts

• High pressure fuel line assembly × 1 — Use OEM Kia part number 31400-2E500 or equivalent
• Fuel line O-rings × 4 — Use OEM specification - typically included with line
• Fuel line sealing washers × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground in a well-ventilated area away from all ignition sources
2. Ensure engine is completely cold - DO NOT work on hot engine
3. Place fire extinguisher within immediate reach of work area
4. Disconnect negative battery terminal and wait 3 minutes for fuel pump controller to discharge
5. Place absorbent pads or shop towels under fuel system components
6. Remove engine cover by pulling upward on all four corners to release clips
7. Locate fuel pump relay in engine compartment fuse box (refer to fuse box diagram)
8. Have drain pan and plastic plugs ready to cap open fuel lines immediately

Procedure

1. 1

   Depressurize fuel system
   Remove the fuel pump relay from the engine compartment fuse box. Reconnect the negative battery terminal temporarily. Attempt to start the engine - it should start briefly then stall as pressure drops. Crank the engine 2-3 additional times to ensure system is fully depressurized. Disconnect negative battery terminal again. Verify zero pressure using fuel pressure gauge on service port before proceeding.
   ⚠️Do not skip depressurization. Even with relay removed, residual pressure can remain in the lines.
2. 2

   Access high pressure fuel line
   The high pressure fuel line runs from the fuel pump module (under rear seat area) forward to the engine fuel rail. From the engine bay, locate where the high pressure line connects to the fuel rail on the driver's side of the engine. Remove the plastic cover over the fuel rail connections if present. Identify the high pressure line - it is a metal hard line, distinct from the lower pressure return hose.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
3. 3

   Disconnect fuel rail end
   Place drain pan under fuel rail connection. Using a flare nut wrench to prevent rounding, carefully loosen the high pressure fuel line fitting at the fuel rail. Expect residual fuel to drain - absorb with shop towels. Once loose, unscrew by hand and remove the line. Immediately cap or plug the fuel rail port to prevent contamination. Remove and discard the old sealing washer and O-ring from the fitting.
   ⚠Use flare nut wrench only - standard wrenches will round off the soft brass fittings.
   ⚠Residual fuel will drain even after depressurization. Be prepared with drain pan and towels.
4. 4

   Remove line mounting brackets
   Trace the high pressure fuel line from the engine bay toward the rear. Remove any mounting brackets or clips securing the line to the chassis or body. Typically there are 2-3 brackets along the length. Use appropriate socket to remove bracket bolts, supporting the fuel line to prevent it from falling.
   Torque spec

   Bracket Bolts19 Nm (14 lb-ft)
5. 5

   Access fuel pump module connection
   Remove the rear seat bottom cushion by locating the two clips at the front edge and pulling firmly upward. Locate the fuel pump access cover on the floor pan (driver's side). Remove the cover screws and lift off the cover. Clean the area around the fuel pump to prevent contamination.
   ℹ️This area may have accumulated dirt and debris. Clean thoroughly before opening fuel system connections.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
6. 6

   Disconnect pump end of high pressure line
   Locate the high pressure line connection on top of the fuel pump module. Place absorbent material around the connection. Using a flare nut wrench, loosen the fitting and disconnect the high pressure line from the pump module. Cap the pump port immediately. Remove and discard old O-rings and sealing washers.
   ⚠Additional fuel will drain from this connection. Have adequate absorbent material ready.
7. 7

   Remove old fuel line
   Carefully route the old high pressure fuel line out from under the vehicle, tracking its path for installation reference. Inspect the routing path for any sharp edges or potential chafe points that may have damaged the old line. Address any issues before installing new line.
   ℹ️Photograph or document the exact routing and any protective grommets or sleeves for reference during installation.
8. 8

   Prepare new fuel line
   Unpack new high pressure fuel line and verify it matches the old line in length and fitting configuration. Install new O-rings on both ends of the new line - lubricate O-rings lightly with clean engine oil or fuel to ease installation and prevent damage. Ensure new sealing washers are positioned correctly at both fittings. Do not reuse old O-rings or washers.
   ⚠️CRITICAL: New O-rings are mandatory. Reusing old O-rings will cause leaks and potential fire hazard.
9. 9

   Route and connect new line to fuel pump
   Route the new high pressure fuel line from the fuel pump area forward toward the engine bay, following the exact path documented during removal. Ensure the line does not contact sharp edges and passes through any protective grommets or sleeves. At the pump module end, hand-thread the fitting into the pump port, ensuring proper thread engagement. Using flare nut wrench and torque wrench, tighten to specification.
   ⚠️Cross-threading will destroy the fitting. Thread by hand first to ensure proper alignment before using wrench.
   Torque spec

   Fuel Line Fittings25 Nm (18 lb-ft)
10. 10

    Secure line and connect to fuel rail
    Continue routing the line forward and reinstall all mounting brackets along the chassis, torquing bracket bolts to specification. Ensure the line is properly supported and not under tension. At the fuel rail end, hand-thread the fitting into the fuel rail port with new O-ring and sealing washer installed. Verify proper thread engagement, then torque to specification using flare nut wrench.
    ⚠️Verify the line is not twisted or kinked. Any restriction can cause fuel starvation or excessive pressure.
    Torque spec

    Bracket Bolts19 Nm (14 lb-ft)

    Fuel Line Fittings25 Nm (18 lb-ft)
11. 11

    Reinstall covers and access panels
    Reinstall the fuel pump access cover and torque screws to specification. Reinstall rear seat bottom cushion ensuring clips engage properly. If applicable, reinstall any fuel rail covers or engine covers removed during access. Double-check that no tools or materials were left in fuel pump area before closing.
    Torque spec

    Cover Screws10 Nm (8 lb-ft)
12. 12

    Reconnect battery and prime fuel system
    Reconnect negative battery terminal. Reinstall fuel pump relay in fuse box. Without starting the engine, turn ignition to ON position (not START) for 5 seconds, then OFF. Repeat this cycle 3-4 times to allow fuel pump to prime the system and build pressure. During priming, inspect all fuel line connections for any signs of leakage.
    ⚠️Watch for fuel leaks during priming. If any leak is observed, immediately turn off ignition, depressurize system, and correct the issue before proceeding.
13. 13

    Start engine and final leak check
    With absorbent materials positioned under all connections, start the engine. Allow it to idle while carefully inspecting all fuel line connections, fittings, and the entire length of the new fuel line for any signs of fuel seepage or leaks. Check both at the fuel rail and at the pump module access area. Run engine for at least 5 minutes, monitoring fuel pressure and leak points continuously.
    ⚠️ANY fuel leak requires immediate engine shutdown and system depressurization. Do not attempt to tighten fittings with engine running.
    ⚠Be prepared to shut down engine immediately if leak is detected. Keep fire extinguisher accessible.

Reassembly

1. All covers, panels, and trim pieces removed during access should be reinstalled securely
2. Verify engine cover clips are fully engaged on all four corners
3. Ensure rear seat cushion is properly locked in place
4. Clean any fuel residue from engine bay and undercarriage with appropriate cleaner
5. Properly dispose of old fuel line, O-rings, and fuel-contaminated materials according to local regulations

Verification

• Visually inspect all fuel line connections for any signs of wetness or fuel seepage with engine running
• Check for fuel odor in cabin or engine bay - any fuel smell indicates a leak that must be addressed
• Verify fuel pressure is within specification (50-60 PSI) using fuel pressure gauge on service port
• Test drive vehicle and verify normal engine performance with no hesitation or fuel starvation symptoms
• After test drive, perform final visual inspection of all connections when engine is hot
• Monitor vehicle for 24-48 hours after repair, checking for fuel odors or visible leaks during cold starts and after driving
• Verify no fuel leak warning lights or diagnostic trouble codes are present using OBD-II scanner

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle