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Fuel Pressure Test

  1. PREPARING 
    1. Remove the rear seat cushion. Refer to REAR SEAT .
    2. Open the service cover (A).
      Fig 1: Identifying Service Cover
      G04862378Courtesy of KIA MOTORS AMERICA, INC.
  2. RELEASE THE INTERNAL PRESSURE 
    1. Disconnect the fuel pump connector (A).
    2. Start the engine and wait until fuel in fuel line is exhausted.
    3. After the engine stalls, turn the ignition switch to OFF position and disconnect the negative (-) terminal from the battery.
      NOTE: Be sure to reduce the fuel pressure before disconnecting the fuel feed hose, otherwise fuel will spill out.
      Fig 2: Identifying Fuel Pump Connector
      G04862379Courtesy of KIA MOTORS AMERICA, INC.
  3. INSTALL THE SPECIAL SERVICE TOOL (SST) FOR MEASURING THE FUEL PRESSURE 
    1. Disconnect the fuel feed hose from the delivery pipe.
      CAUTION: Cover the hose connection with a shop towel to prevent splashing of fuel caused by residual pressure in the fuel line.
    2. Install the Fuel Pressure Gage Adapter (09353-38000) between the delivery pipe and the fuel feed hose.
    3. Connect the Fuel Pressure Gage Connector (09353-24000) to the Fuel Pressure Gage Adapter (09353-38000).
    4. Connect the Fuel Pressure Gage and Hose (09353-24100) to Fuel Pressure Gage Connector (09353-24000).
    5. Connect the fuel feed hose to the Fuel Pressure Gage Adapter (09353-38000).
      Fig 3: Identifying Fuel Feed Hose, Fuel Pressure Gage Adapter (09353-38000) With Delivery Pipe
      G04862380Courtesy of KIA MOTORS AMERICA, INC.
  4. INSPECT FUEL LEAKAGE ON CONNECTION 
    1. Connect the battery negative (-) terminal.
    2. Apply battery voltage to the fuel pump terminal and activate the fuel pump. With fuel pressure applied, check that there is no fuel leakage from the fuel pressure gauge or connection part.
  5. FUEL PRESSURE TEST 
    1. Disconnect the negative (-) terminal from the battery.
    2. Connect the fuel pump connector.
    3. Connect the battery negative (-) terminal.
    4. Start the engine and measure the fuel pressure at idle.

      Standard Value: 343 kPa (3.5 kgf/cm2 , 49.8 psi)

      • If the measured fuel pressure differs from the standard value, perform the necessary repairs using the table below.
        FUEL PRESSURE REFERENCE CHART

        Condition Probable Cause Suspected Area
        Fuel Pressure too low Clogged fuel filter Fuel filter
        Fuel leak on the fuel-pressure regulator that is assembled on fuel pump because of poor seating of the fuel-pressure regulator. Fuel Pressure Regulator
        Fuel Pressure too High Sticking fuel pressure regulator Fuel Pressure Regulator
    5. Stop the engine and check for a change in the fuel pressure gauge reading.

      After engine stops, the gage reading should hold for about 5 minutes

      • Observing the declination of the fuel pressure when the gage reading drops and perform the necessary repairs using the table below.
        FUEL PRESSURE REFERENCE CHART

        Condition Probable Cause Suspected Area
        Fuel pressure drops slowly after engine is stopped Injector leak Injector
        Fuel pressure drops immediately after engine is stopped The check valve within the fuel pump is open Fuel Pump
  6. RELEASE THE INTERNAL PRESSURE 
    1. Disconnect the fuel pump connector (A).
    2. Start the engine and wait until fuel in fuel line is exhausted.
    3. After the engine stalls, turn the ignition switch to OFF position and disconnect the negative (-) terminal from the battery.
      NOTE: Be sure to reduce the fuel pressure before disconnecting the fuel feed hose, otherwise fuel will spill out.
      Fig 4: Identifying Fuel Pump Connector
      G04862381Courtesy of KIA MOTORS AMERICA, INC.
  7. REMOVE THE SPECIAL SERVICE TOOL (SST) AND CONNECT THE FUEL LINE 
    1. Disconnect the Fuel Pressure Gage and Hose (09353-24100) from the Fuel Pressure Gage Connector (09353-24000).
    2. Disconnect the Fuel Pressure Gage Connector (09353-24000) from the Fuel Pressure Gage Adapter (09353-38000).
    3. Disconnect the fuel feed hose from the Fuel Pressure Gage Adapter (09353-38000).
    4. Disconnect the Fuel Pressure Gage Adapter (09353-38000) from the delivery pipe.
      CAUTION: Cover the hose connection with a shop towel to prevent splashing of fuel caused by residual pressure in the fuel line.
    5. Connect the fuel feed hose to the delivery pipe.
  8. INSPECT FUEL LEAKAGE ON CONNECTION 
    1. Connect the battery negative (-) terminal.
    2. Apply battery voltage to the fuel pump terminal and activate the fuel pump. With fuel pressure applied, check that there is no fuel leakage from the fuel pressure gauge or connection part.
    3. If the vehicle is normal, connect the fuel pump connector.
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