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 intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

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

    5. Read the DTCs.

      Result
      Result Proceed to
      No output A
      DTC is output B

    B

    GO TO DTC CHART Click here

    A

  2. PERFORM BASIC FUNCTION


    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

    B

    END

    A

  3. READ VALUE USING INTELLIGENT TESTER


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester 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 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 INTELLIGENT TESTER


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester 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 INTELLIGENT TESTER


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester 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 (for CVT), or neutral (for M/T) and the vehicle stationary.

    6. Read the value.

      Test Condition Result
      High

      VALVEMATIC Current Angle: 260°CA

      MAP: 20 to 35 kPa (150 to 263 mmHg, 5.91 to 10.3 in.Hg)
      Low

      VALVEMATIC Current Angle: 106°CA

      MAP: 70 to 100 kPa (525 to 750 mmHg, 20.7 to 29.5 in.Hg)
      Result
      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).


    OK

    PERFORM SIMULATION TEST

    NG

    CHECK VALVEMATIC SYSTEM