SFI SYSTEM Lack of Power or Hesitation

DESCRIPTION

The VALVEMATIC system is able to continuously change the valve lift amount and valve timing. For engines equipped with a VALVEMATIC system, when a part such as a rocker arm in the camshaft housing has mechanical problems, the valve lift amount does not change and problems occur, such as a lack of engine power or rough idling.

CAUTION / NOTICE / HINT

A lack of engine power occurs when the throttle valve is malfunctioning or when there is a clog in the intake or exhaust system. Therefore, during the inspection, confirm that there are no clogs in any parts.

Tech Tips


  • When the throttle valve is malfunctioning, even if the accelerator pedal is fully depressed when the engine is running, the throttle does not fully open.

  • When there is a clog in the intake system, even if the accelerator pedal is fully depressed, the MAP is not the same as the atmospheric pressure.

When performing this inspection on a vehicle equipped with the VALVEMATIC, perform the following procedures first in order to confirm that there are no VVT system malfunctions.


  1. Perform the VVT system Active Test and confirm that the VVT follows the VVT target.

  2. If the VVT system Active Test results are normal, perform the VALVEMATIC system Active Test.

Note

When the vehicle is not equipped with the VALVEMATIC, even if the VVT system inspection (the inspection that checks if idling becomes unstable when changing the VVT to the most advanced and retarded positions through the Active Test) is performed, it cannot be determined that the malfunction is in the VVT system.

PROCEDURE


  1. CHECK WHETHER DTC OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC is output B

    B

    GO TO DTC CHART Click here

    A

  2. PERFORM BASIC INSPECTION


    1. Check the air cleaner filter element.

      Tech Tips

      If the air cleaner filter element is dirty, clean or replace it.

    2. Check if there are any clogs in the intake or exhaust system.

    3. Check the ignition timing Click here.

    4. Check the fuel pressure Click here.

    5. Check the spark Click here.

    6. Measure the cylinder compression pressure Click here.

      Result
      Result Proceed to
      Everything normal A
      Repaired problem area but malfunction reoccurs A
      Repaired problem area and malfunction does not reoccur B

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the intake system, exhaust system, ignition system or engine assembly Click here.


    B

    END

    A

  3. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Short FT #1, Long FT #1, AFS Voltage B1S1 and O2S B1S2.

    5. Read the value while the driving the vehicle.

      Result
      Result Proceed to
      No abnormal values in Data List A
      Abnormal values in Data List B

    B

    CHECK FUEL SYSTEM

    A

  4. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank1).

    5. Read the value.

      Result
      Result Proceed to
      VVT angle follows VVT target angle A
      VVT angle does not follow VVT target angle B

    B

    CHECK VVT SYSTEM

    A

  5. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VALVEMATIC (ENG ON).

    5. Maintain an engine speed of 3000 rpm with the shift lever in P and the vehicle stationary.

    6. Read the value.

      Test Condition Result
      High VALVEMATIC Current Angle: 250 deg(CA) or more and shaft retracts
      Low VALVEMATIC Current Angle: 100 to 120 deg(CA) and shaft extends
      OK
      Change in MAP during the Active Test

      Tech Tips


      • When the vehicle is driven while there is a malfunction in the VALVEMATIC system and the valve lift amount is fixed at the minimum, the vehicle speed cannot exceed 10 to 60 km/h (6 to 37 mph).

      • If the intake valve advance angle is within the VALVEMATIC operation prohibition range depending on the operating state of the VVT system, the Active Test "Activate the VALVEMATIC (ENG ON)" is prohibited. If the advance angle cannot be detected due to a malfunction in the VVT system, the Active Test "Activate the VALVEMATIC (ENG ON)" is prohibited.


    OK

    PERFORM SIMULATION TEST

    NG

    CHECK VALVEMATIC SYSTEM