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Home >> Hyundai >> 2004 >> Elantra GLS, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel System >> Fuel Delivery System >> Fuel Pump (FP) >> Fuel Pressure Test
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Fuel Pressure Test

  1. Press the two tabs under the rear seat and raise the seat, then detach the inspection panel of the fuel pump.
  2. To reduce the internal pressure of the fuel lines and hoses, first start the engine with the fuel pump disconnected and wait until it stops by itself.
    NOTE: Be sure to reduce the fuel pressure before disconnecting the fuel main pipe and hose, otherwise fuel will spill out.
  3. Disconnect the battery negative (-) terminal and then connect the fuel pump harness connector
  4. Using the fuel pressure gauge, adaptor and connector, install the fuel-pressure gauge to the fuel delivery pipe. Tighten the bolt to the specified torque.
    Fig 1: Using Fuel Pressure Gauge To Check Fuel Pressure
    G00748437Courtesy of HYUNDAI MOTOR CO.

    Tightening Torque 

    Fuel pressure gauge to fuel delivery pipe:

    25 - 35Nm (250 - 350 kg. cm, 18 - 26 Ib. ft)

  5. Connect the battery's negative (-) terminal.
  6. Apply battery voltage to the terminal for the pump drive and activate the fuel pump. Then, with fuel pressure applied, check that there is no fuel leak from the pressure gauge or connections.
  7. Start the engine and let it idle.
  8. Measure the fuel pressure.

    Standard value : 350 kPa (3.5 kg/cm2 , 49.8 psi)

  9. If the result of the measurements made in steps (7) and (8) are not within the standard value, use the table below to determine the probable cause, and perform the necessary repairs.
    Fig 2: Fuel Pressure Too High/Too Low - Probable Cause Table (Engine Running)
    G00748438Courtesy of HYUNDAI MOTOR CO.
  10. Stop the engine and check for a change in the fuel pressure gauge reading, which should hold for approximately 5 minutes. If the gauge indication drops, observe the rate of drop. Determine and correct the causes according to the following table.
    Fig 3: Fuel Pressure Drops After Engine Is Shut Off - Probable Cause Table
    G00748439Courtesy of HYUNDAI MOTOR CO.
  11. Release the pressure in the fuel line.
  12. Disconnect the hose and the gauge.
    CAUTION: Cover the hose connection with a shop towel to prevent splashing of fuel caused by residual fuel pressure in the fuel line.
  13. Replace the O-ring at the end of the hose.
  14. Connect the fuel hose to the delivery pipe and tighten to the specified torque.
  15. Check for fuel leaks.
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