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


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

  • If there is a clog in the intake system, even if the accelerator pedal is fully depressed, value for MAP in the Data List is not the same as the atmospheric pressure.

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


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

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

Note

When the vehicle is not equipped with 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 engine switch on (IG).

    3. Turn the GTS on.

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

    5. Read the DTCs.


      Powertrain > Engine and ECT > Trouble Codes
      Result
      Result Proceed to
      DTCs are not output A
      DTCs are output B

    B

    GO TO DTC CHART Click here

    A

  2. PERFORM BASIC FUNCTION


    1. Check the air cleaner filter element sub-assembly.

      Tech Tips

      If the air cleaner filter element sub-assembly 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 recurs
      Repaired problem area and malfunction does not recur 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 engine switch on (IG).

    3. Turn the GTS on.

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


      Powertrain > Engine and ECT > Data List
      Tester Display
      AFS Voltage B1S1
      O2S B1S2
      Short FT B1S1
      Long FT B1S1

    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 GTS (CONTROL THE VVT SYSTEM (BANK 1))


    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 / Control the VVT System (Bank1) / Data List / Ptrl Valve Control / VVT Change Angle #1.


      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Control the VVT System (Bank1)
      Data List Display
      VVT Change Angle #1

    5. Read the value.

      Result
      Result Proceed to
      "VVT Change Angle #1" value changes A
      "VVT Change Angle #1" value does not change B

    B

    CHECK VVT SYSTEM Click here

    A

  5. PERFORM ACTIVE TEST USING GTS (ACTIVATE THE VALVEMATIC(ENG ON))


    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) / Data List / Primary / MAP and VALVEMATIC Current Angle.


      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Activate the VALVEMATIC(ENG ON)
      Data List Display
      MAP
      VALVEMATIC Current Angle

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

    6. Read the value.

      Standard
      GTS Operation 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 30 to 60 km/h (19 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.

      Result
      Proceed to
      OK
      NG

    OK

    PERFORM SIMULATION TEST

    NG

    CHECK VALVEMATIC SYSTEM Click here