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Home >> Kia >> 2005 >> Optima EX, 2.4 6 >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System/Fuel System - 2.4L (A/T) >> MFI Control System >> Fuel Injector >> Troubleshooting Hints
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Troubleshooting Hints

  1. If the engine is hard to start when hot, check for fuel pressure and injector leaks.
  2. If the injectors do not operate when the engine is cranked, then check the following:
    • Defective power supply circuit to the ECU, faulty ground circuit
    • Defective control relay
    • Defective Crankshaft Position (CKP) Sensor or Camshaft Position (TDC) Sensor
  3. If there is any cylinder whose idle state remains unchanged when the fuel injectors are cut one after another during idling, check for the following items about that cylinder.
    • Injector and harness
    • Ignition plug and high tension cable
    • Compression pressure
  4. If the injection system is OK but the injector drive time is out of specification, check for the following items.
    • Poor combustion in the cylinder (faulty ignition plug, ignition coil, compression pressure, etc.)
    • Loose EGR valve seating