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Circuit/System Testing

  1. Verify none of the following conditions listed below exist:
    • Damage, carbon tracking or fluid intrusion of the spark plug boots and/or spark plugs
    • Vacuum hose splits, kinks and incorrect connections
    • Engine vacuum leaks
    • Crankcase ventilation system for vacuum leaks
    • Fuel pressure that is too low or too high-Refer to Fuel System Diagnosis .
    • Contaminated fuel-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Exhaust system restrictions
      • If a condition exists 

        Repair or replace as necessary.

      • If no conditions exist 
  2. Ignition OFF, remove the appropriate T 8 Ignition Coil from the spark plug and connect the EL 26792  HEI Spark Tester, engine Cranking.
    NOTE: An erratic or weak spark is considered a no spark condition.
  3. Verify the spark output.
    • If the output is good 
  4. Ignition OFF.
  5. Verify the conditions listed below. Refer to Ignition System Specifications .
    • The correct spark plug type
    • The correct spark plug gap
    • The correct spark plug torque
    • If a condition exists 

      Repair or replace as necessary.

    • If no conditions exist 
  6. Exchange the suspect spark plug with another cylinder that is operating correctly.
  7. Engine Running.
  8. Verify the scan tool Cylinder 1-4 Current Misfire Counter does not increment for the cylinder where the suspect spark plug was installed.
    • If increments 

      Replace the spark plug.

    • If does not increment 
  9. Test or inspect for the conditions listed below:
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