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Home >> Hyundai >> 2004 >> Accent Base >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel System >> General >> Inspection >> Service Adjustment Procedures >> Fuel Pressure Test
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Fuel Pressure Test

  1. Press the two taps under the rear seat and raise the seat, then detach the inspection panel of the fuel pump.
    2. Fig 1: Raising Rear Seat
    G03851565Courtesy of HYUNDAI MOTOR CO.
  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.
    NOTE: For additional information regarding fuel filter location, please refer to the following Technical Service Bulletin from Hyundai: 2003 - 2005 ACCENT FUEL FILTER LOCATION - SHOP MANUAL CORRECTION .
    Fig 2: Identifying Fuel Filter And Fuel Pump
    G03851566Courtesy of HYUNDAI MOTOR CO.
  3. Disconnect the battery negative (-) terminal and then connect the fuel pump harness connector.
  4. Using the fuel pressure gauge adapter (09353-24000, 09353-24100, 09353-38000), install the fuel-pressure gauge to the fuel rail. Tighten the bolt to the specified torque.
    Fig 3: Installing Fuel-Pressure Gauge To Fuel Rail Using Fuel Pressure Gauge Adapter
    G03851567Courtesy of HYUNDAI MOTOR CO.

    Tightening Torque 

    Fuel pressure gauge to fuel filter:

    25~35 Nm (250~350 kg.cm, 18~26 lb.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 make the necessary repairs.
    FUEL PRESSURE TROUBLESHOOTING

    Condition Probable cause Remedy
    Fuel pressure too low
    1. Clogged fuel filter.
    2. Fuel leak on the return side, caused by poor seating of the fuel-pressure regulator.
    1. Replace fuel filter.
    2. Replace fuel pump.
    Fuel pressure too high
    1. Sticking fuel-pressure regulator.
    2. Clogged or bent fuel return hose or pipe.
    1. Replace fuel pump.
    2. Repair or replace hose or pipe.
  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 remove the causes according to the following table.
    FUEL PRESSURE DROP TROUBLESHOOTING

    Condition Probable cause Remedy
    Fuel pressure drops slowly after engine is stopped
    1. Injector leak.
    1. Replace injector.
    Fuel pressure drops immediately after engine is stopped
    1. The check valve within the fuel pump is open.
    1. Replace fuel pump.
  11. Reduce 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 with the specified torque
  15. Check for fuel leaks.
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