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Inspection procedure 5: Hard starting
 
 
 
 
COMMENT
  • In cases such as the above, the cause is usually either weak spark, improper air-fuel mixture or low compression.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this case:)
  • Fuel pump system failed.
  • Ignition system failed.
  • Injector system failed.
  • Poor compression.
  • EGR system failed.
  • Contaminated fuel.
  • ECM failed.

 
 
DIAGNOSIS
STEP 1. Check if the EGR valve sounds during initialization.
Is the initialization sound heard in the EGR valve?
Go to Step 2.
Refer to GROUP 17, Emission Control - Exhaust Gas Recirculation (EGR) System - EGR Valve (stepper motor) Check .
 
STEP 2. Using scan tool (M.U.T.-IIISE), read the diagnostic trouble code (DTC).
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
(1) Connect scan tool (M.U.T.-IIISE). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-IIISE) .
(2) Turn on the power supply mode of the electric motor switch.
(3) Read the DTC.
(4) Turn off the power supply mode of the electric motor switch.
Is any DTC set?
Refer to Diagnostic Trouble Code Chart .
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T.-IIISE), check data list.
(1) Turn on the power supply mode of the electric motor switch.
(2) Check the following items in the data list. Refer to Data List Reference Table .
  1. Item 1: Power Supply Voltage
  2. Item 6: Engine Coolant Temperature Sensor
(3) Turn off the power supply mode of the electric motor switch.
Is the sensor operating properly?
Go to Step 4.
Repair or replace it. Then confirm that the malfunction symptom is eliminated.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check actuator test.
(1) Turn on the power supply mode of the electric motor switch.
(2) Set scan tool (M.U.T.-IIISE) to the actuator test mode for item 9, Fuel Pump.
  • An operation sound of the fuel pump should be heard.
(3) Turn off the power supply mode of the electric motor switch.
Is the actuator operating properly?
Go to Step 5.
Repair or replace it. Then confirm that the malfunction symptom is eliminated.
 
STEP 5. Check the ignition timing.
Refer to GROUP 11A, On-vehicle Service - Ignition Timing Check .
Is the ignition timing normal?
Go to Step 6.
Repair or replace it. Then confirm that the malfunction symptom is eliminated.
 
STEP 6. Check the injector.
Refer to Injector check .
Is the measured resistance normal?
Go to Step 7.
Replace the faulty injector. Then confirm that the malfunction symptom is eliminated.
 
STEP 7. Check of harness damage in power supply line between MFI relay connector and injector connector.
Are the harness wires in good condition?
Go to Step 8.
Repair them. Then confirm that the malfunction symptom is eliminated.
 
STEP 8. Check of short to ground, open circuit and harness damage in INJ1, INJ2, INJ3 and INJ4 line between injector connector and ECM connector.
Are the harness wires in good condition?
Go to Step 9.
Repair them. Then confirm that the malfunction symptom is eliminated.
 
STEP 9. Check the ignition system.
(1) Connect the timing light to terminal power supply line of the ignition coil connectors in order.
(2) Crank the engine.
  • The timing light flashes.
(3) Turn off the power supply mode of the electric motor switch.
Does the timing light flash?
Go to Step 10.
Refer to Inspection Procedure - Ignition Circuit System .
 
STEP 10. Check the spark plugs.
Refer to GROUP 16, Ignition System - On-vehicle Service - Spark Plug Check and Cleaning .
Are there any abnormalities?
Replace the spark plug. Then confirm that the malfunction symptom is eliminated.
Go to Step 11.
 
STEP 11. Check the ignition coil.
Refer to GROUP 16, Ignition System - On-vehicle Service - Ignition Coil Check .
Are there any abnormalities?
Replace the ignition coil. Then confirm that the malfunction symptom is eliminated.
Go to Step 12.
 
STEP 12. Check the compression pressure.
Refer to GROUP 11A, On-vehicle Service - Compression Pressure Check .
Is the compression pressure normal?
  • Check the following items, and repair or replace the defective items.
    1. Check if fuel is contaminated.
    2. Check if the injectors are clogged.
  • Then confirm that the malfunction symptom is eliminated.
Repair it. Then confirm that the malfunction symptom is eliminated.