Inspection Procedure 9: Poor acceleration


PROBABLE CAUSES



  • Failed boost pressure control system
  • Failed turbocharger
  • Improper fuel used
  • Fuel contaminated with foreign matter
  • Injector leaking or clogged
  • Failed injector
  • Fuel injection learning failure
  • Fuel filter clogged
  • Fuel line leaking or clogged
  • Failed fuel pressure limiter valve
  • Failed fuel pressure sensor
  • Failed supply pump (suction control valve)
  • Failed supply pump correction learning
  • Failed exhaust gas recirculation system operation
  • Failed valve clearance adjustment
  • Failed engine-ECU
  • Compression pressure low
  • Air cleaner clogged

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 idling condition.

Q. Is the check result normal?
Go to Step 3 .
Proceed to troubleshooting for improper idling (Refer to Inspection Procedure 7 ).

STEP 3. Check injector identification code.

  • Check injector identification code (Refer to GROUP 00 - Precautions Before Service - Injector Identification code Registration Procedure ).

Q. Is the check result normal?
Go to Step 4 .
Register the injector ID.

STEP 4. M.U.T.-III data list.

  • Refer to Data List Reference Table .

  1. Item 5: Barometric pressure sensor
  2. Item 6: Manifold absolute pressure sensor
  3. Item 7: Engine coolant temperature sensor
  4. Item 8: No. 2 intake air temperature sensor
  5. Item 9: Accelerator pedal position sensor (main)
  6. Item 10: Accelerator pedal position sensor (sub)
  7. Item 13: Accelerator pedal position sensor (main) learned closed position
  8. Item 16: Exhaust gas recirculation valve position sensor
  9. Item 17: Exhaust gas recirculation valve target position
  10. Item 21: Fuel temperature sensor
  11. Item 43: No. 1 intake air temperature sensor
  12. Item 45: Throttle position sensor
  13. Item 46: Throttle position sensor learned closed position

Q. Are the check results normal?
Go to Step 5 .
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 5. Supply pump correction learning.

  • Carry out the supply pump correction learning (Refer to GROUP 00 - Precautions Before Service - Supply Pump Correction Learning ).

Q. Does trouble symptom persist?
Go to Step 6 .
The procedure is complete.

STEP 6. Small injection quantity learning.

  • Carry out the small injection quantity learning procedure (Refer to GROUP 00 - Precautions Before Service - Small Injection Quantity Learning Procedure ).

Q. Does trouble symptom persist?
Go to Step 7 .
The procedure is complete.

STEP 7. Check air cleaner.

Q. Is the check result normal?
Go to Step 8 .
Replace the air cleaner.

STEP 8. Confirm the using fuel.

Q. Is the specified fuel being used?
Go to Step 9 .
Replace the fuel.

STEP 9. Checking the turbocharging pressure.

  • Check the turbocharging pressure (Refer to GROUP 15 - On-vehicle Service - Turbocharger Supercharging Pressure Check ).

Q. Is the check result normal?
Go to Step 10 .
Repair or replace the failed item.

STEP 10. Check fuel supply line.

  • Check for fuel leakage and clogging.
  • Check fuel filter for clogging.

Q. Is the check result normal?
Go to Step 11 .
Repair or replace the failed item.

STEP 11. Priming (air bleeding)

  • Bleed air.

Q. Does trouble symptom persist?
Go to Step 12 .
The procedure is complete.

STEP 12. M.U.T.-III actuator test.

  • Refer to Actuator Test Reference Table .

  1. Item 19: Suction control valve

Q. Is the check result normal?
Go to Step 13 .
Replace the suction control valve. After replacing the suction control valve, learn the supply pump (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 13. Check suction control valve itself.

  • Check suction control valve itself (Refer to ).

Q. Is the check result normal?
Go to Step 14 .
Replace the suction control valve. After replacing the suction control valve, learn the supply pump (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 14. M.U.T.-III data list.

  • Refer to Data List Reference Table .

  1. Item 63: Rail pressure sensor
  2. Item 64: Rail pressure target

Q. Are the check results normal?
Go to Step 16 .
Go to Step 15 .

STEP 15. Replace the fuel pressure sensor.

  • Replace the common-rail assembly.

Q. Does trouble symptom persist?
Go to Step 20 .
The procedure is complete.

STEP 16. Check the waveforms of crank angle sensor and camshaft position sensor.

  • Check the output waveforms on an oscilloscope (Refer to ).

Q. Is the check result normal?
Go to Step 17 .
Proceed to the inspection procedure by diagnosis code for the abnormal waveform (Refer to Inspection Chart for Diagnosis Code ).

STEP 17. M.U.T.-III actuator test.

  • Refer to Actuator Test Reference Table .

  1. Item 15: Injector No. 1
  2. Item 16: Injector No. 2
  3. Item 17: Injector No. 3
  4. Item 18: Injector No. 4

Q. Are the check results normal?
Go to Step 18 .
Replace the injector at the failed cylinder. After replacing the Injector, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 18. Check compression pressure.

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

Q. Is the check result normal?
Go to Step 19 .
Check and repair the engine itself.

STEP 19. Check injector itself.

  • Check injector itself (Refer to ).

Q. Is the check result normal?
Go to Step 20 .
Replace the injector at the failed cylinder. After replacing the Injector, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 20. Check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).