Inspection Procedure 11: Hesitation, Sag, Poor Acceleration, Stumble or Surge


COMMENT ON TROUBLE SYMPTOM



  • The failure could possibly be caused by the failed ignition system, improper air-fuel ratio, faulty compression pressure and so on.

PROBABLE CAUSES



  • Failed air-fuel ratio control system
  • Failed ignition system
  • Failed fuel system
  • Failed electronic-controlled throttle valve system
  • Contamination around the throttle valve
  • Improper compression pressure
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is the diagnosis code set?
Inspection chart for diagnosis code (Refer to ).
Go to Step 2 .

STEP 2. Check injector for operating sound.

  • Check injector for operating sound (Refer to ).

Q. Can operating sound be heard?
Go to Step 3 .

    Check the injector system of the defective cylinder.
    (Refer to Code No. P0201: No. 1 Injector System ).
    (Refer to Code No. P0202: No. 2 Injector System ).
    (Refer to Code No. P0203: No. 3 Injector System ).
    (Refer to Code No. P0204: No. 4 Injector System ).

STEP 3. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item 5: Intake air temperature sensor
  2. Item 6: Engine coolant temperature sensor
  3. Item 8: Manifold absolute pressure sensor
  4. Item 11: Accelerator pedal position sensor (main)
  5. Item 12: Accelerator pedal position sensor (sub)
  6. Item 13: Throttle position sensor (main)
  7. Item 15: Throttle position sensor (sub)
  8. Item 36: V.V.T.phase angle

Q. Are the check results normal?
Go to Step 4 .
Perform the diagnosis code classified check Procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 4. Check purge control solenoid valve itself.

  • Check purge control solenoid valve itself (Refer to GROUP 17 - Emission Control <MPI> - Evaporative Emission Control System - Purge Control Solenoid Valve Check ).

Q. Is the check result normal?

Go to Step 5 .
Replace the purge control solenoid valve.

STEP 5. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item AC: Oxygen sensor (front)
  2. Item AD: Oxygen sensor (rear)

Q. Are the check results normal?

Go to Step 6 .
Perform the diagnosis code classified check Procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 6. Visual check of ignition spark.

  • Remove the spark plug and install it to the ignition coil.
  • Connect the ignition coil connector.
  • Disconnect all injector connectors.
  • At the engine start, check each spark plug produces a spark.

Q. Is the check result normal?
Go to Step 7 .
Check ignition circuit system (Refer to Inspection Procedure 23 ).

STEP 7. Check throttle body (throttle valve portion) for contamination.

Q. Is the check result normal?

Go to Step 8 .
Clean throttle body (throttle valve portion) (Refer to ).

STEP 8. Check compression pressure.

  • Check compression pressure (Refer to GROUP 11A - On-vehicle Service - Compression Pressure Check ).

Q. Is the check result normal?

Go to Step 9 .
Repair.

STEP 9. Fuel pressure measurement.

  • Fuel pressure measurement (Refer to ).

Q. Is the check result normal?

Replace the engine-ECU.
Repair.