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Spark Plug: Troubleshooting

WARNING:
  • When working on the high voltage system, the work should be performed by technicians who have completed the relevant training. A lack of understanding of the high voltage system can lead to serious accidents due to electric shock or short circuit.
  • When working on the high voltage system or related components, be sure to observe and be aware of the "HIGH VOLTAGE SYSTEM GENERAL SAFETY INFORMATION AND CAUTION ". If not, it may cause serious accidents due to electric shock or short circuit.
  • When working on high voltage system, make sure to check the PERSONAL PROTECTIVE EQUIPMENT (PPE) and HIGH VOLTAGE SHUT-OFF PROCEDURES .
  1. Check the DTC code by using the KDS (Refer to "DTC INDEX (PHEV) ").
    G15787448Courtesy of KIA MOTORS AMERICA, INC.
  2. Check the connection condition of the ignition coil connectors (A).
    G15787449Courtesy of KIA MOTORS AMERICA, INC.
  3. Check the installation condition of the ignition coils (A).

    Tightening torque: 

    9.8 - 11.8 N.m (1.0 - 1.2 kgf.m, 7.2 - 8.7 lb.ft)

    G15787450Courtesy of KIA MOTORS AMERICA, INC.
  4. Remove the spark plug.

    (Refer to Spark Plug -  "REMOVAL AND INSTALLATION ")

  5. Visual inspection of the spark plugs.

    Spark plug electrode gap:  1.0 - 1.1 mm (0.039 - 0.043 in.)

    Symptom Suspected Cause Correction
    G15787451Courtesy of KIA MOTORS AMERICA, INC.

    Melting Electrode    		 Abnormal Combustion, Overheat Replace the Spark Plug
    G15787452Courtesy of KIA MOTORS AMERICA, INC.

    Carbon and Foreign Matter
    G15787453Courtesy of KIA MOTORS AMERICA, INC.

    Ring Crack    		 Abnormal Combustion, External Shock
    G15787454Courtesy of KIA MOTORS AMERICA, INC.

    Vertical Crack    		 External Shock
    G15787455Courtesy of KIA MOTORS AMERICA, INC.

    Overheat    		 Abnormal Combustion
    Symptom Suspected Cause Correction
    G15787456Courtesy of KIA MOTORS AMERICA, INC.

    Poor Gap    		 Physical Damage Replace the Spark Plug
    G15787457Courtesy of KIA MOTORS AMERICA, INC.

    Flash Over    		 Excessive Electrode Wear Replace the Spark Plug, Ignition Coil
    G15787458Courtesy of KIA MOTORS AMERICA, INC.

    Corrosion/Rust    		 Remaining Oil Mist Reassemble the Spark Plug
  6. Check the resistance between the spark plugs terminal (A) and probe (B) by using a multi-tester or a resistance meter.

    Specified value:  2 - 20 kΩ

    G15787459Courtesy of KIA MOTORS AMERICA, INC.
    NOTE:
    • Avoid the contact resistance between probe and spark plugs (when it occurs, the measured value is not stabilized).
    • Be careful not to damage center electrode (A) while measuring resistance.
    G15787460Courtesy of KIA MOTORS AMERICA, INC.
  7. Test for changing position of each ignition coil and spark plug.
    1. Remove the spark plug (A) and ignition coil (B) from the misfiring cylinder and exchange them with one of the other cylinders.

      (Refer to Spark Plug -  "REMOVAL AND INSTALLATION ")

      G15787461Courtesy of KIA MOTORS AMERICA, INC.
    2. Replace the spark plugs, if misfire moves along the spark plugs.
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