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Home >> Ford >> 2015 >> Explorer Limited, 3.5L Eng VIN 8, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (Except Diesel & Hybrid) - Pinpoint Tests H - JD >> Pinpoint Test JC: Secondary Ignition (Coil Pack) >> Test Procedure

Test Procedure

  1. JC1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) 

    Are DTCs P0300, P0301, P0302, P0303 or P0304? 

    Yes No
    For DTC P0300, GO to JC2  .
    For all others, GO to  JC10.    		 For symptoms without DTCs, GO to JC2  .
    For all others, RETURN to SYMPTOM CHARTS for further direction.
  2. JC2 CYLINDER POWER BALANCE TEST 
    NOTE: The IDS test referenced in this step may not be available on all vehicles. Follow the YES answer if the IDS test is not available.
    • Carry out the Power Balance Test. Refer to the instruction manual provided by the scan tool manufacturer.

    Are all cylinders contributing correctly during the power balance test? 

    Yes No
    GO to JC3  . For a coil pack using an engine analyzer, GO to  JC4.
    For a coil pack not using an engine analyzer, GO to  JC10.
  3. JC3 VISUAL INSPECTION OF THE IGNITION SYSTEM 
    • Visually inspect the engine compartment to make sure all coils and spark plug wires are correctly and securely connected.
    • Examine all wiring harnesses and connectors for damaged, burned or overheated insulation and loose or broken conditions.
    • Visually inspect the interior and exterior surfaces of the coil tower for damage or carbon tracking.
    • Visually inspect the interior and exterior surfaces of the spark plug wire boots for damage or carbon tracking.
    • Make sure the vehicle battery is in good condition and all accessories are turned off.

    Is a concern present? 

    Yes No
    REPAIR as necessary.
    Clear the PCM DTCs. REPEAT the self-test.    		 For a coil pack using an engine analyzer, GO to JC4  .
    For a coil pack not using an engine analyzer, GO to  JC10.
  4. JC4 CHECK FOR THE IGNITION PATTERN 
    • Connect an engine analyzer to diagnose concerns in the secondary side of the ignition system.
    • Observe the pattern on a scope while cranking the engine.
      Fig 1: Ignition Pattern
      G09956994Courtesy of FORD MOTOR CO.

    Is the pattern flat, which indicates no ignition spark on all cylinders? 

    Yes No
    GO to PINPOINT TEST JE . GO to JC5  .
  5. JC5 CHECK FOR A NORMAL IGNITION PATTERN 
    NOTE: Spark plugs may be fired more than once per combustion event. Multi-strike operating mode is RPM dependent.
    • Ignition ON, engine running. If no start, crank the engine.
      Fig 2: Normal Ignition Pattern
      G06054036Courtesy of FORD MOTOR CO.

    Are the patterns even and is the average value of spark plug firing voltage between 9 kV and 15 kV (higher during engine crank/no start)? 

    Yes No
    GO to PINPOINT TEST Z . GO to JC6  .
  6. JC6 CHECK FOR MISSING SPARK PATTERNS 
    • Observe for missing spark pattern.
      Fig 3: Missing Spark Pattern
      G06054037Courtesy of FORD MOTOR CO.

    Is the spark pattern inconsistent? 

    Yes No
    INSPECT the spark plug wires for missing cylinders. MEASURE the resistance of the spark plug wires. INSTALL a new spark plug wire if the resistance is greater than 7, 000 ohms per 30.5 cm (1 foot). REFER to the service information , Engine Ignition.
    Clear the PCM DTCs. REPEAT the self-test.
    GO to JE2 .    		 GO to JC7  .
  7. JC7 CHECK FOR A HIGH SPARK PLUG FIRING VOLTAGE 
    • Observe for a high spark plug firing voltage.
      Fig 4: High Spark Plug Firing Voltage Pattern
      G06054038Courtesy of FORD MOTOR CO.

    Is the average value of the spark plug firing voltage greater than 15 kV? 

    Yes No
    INSPECT the spark plug wires for missing cylinders. MEASURE the resistance of the spark plug wires. INSTALL a new spark plug wire if the resistance is greater than 7, 000 ohms per 30.5 cm (1 foot). REFER to the service information , Engine Ignition.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to JC8  .
  8. JC8 CHECK FOR LOW SPARK PLUG FIRING VOLTAGE 
    • Check the spark plug firing voltage average pattern.
      Fig 5: Spark Plug Firing Voltage Average Pattern
      G06054039Courtesy of FORD MOTOR CO.

    Is there consistently low spark plug firing voltage or sloping sparkline on one or more cylinders? 

    Yes No
    INSPECT the spark plug wires for missing cylinders. MEASURE the resistance of the spark plug wires. INSTALL a new spark plug wire if the resistance is greater than 7, 000 ohms per 30.5 cm (1 foot). MEASURE the resistance of the spark plugs. INSTALL a new spark plugs if the resistance is lower than 2, 000 or higher than 12, 000 ohms. REFER to the service information , Engine Ignition.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to JC9  .
  9. JC9 CHECK FOR EVENNESS BETWEEN CYLINDERS 
    • Check the spark plug firing voltage average pattern.
      Fig 6: Spark Plug Firing Voltage Average Pattern
      G06054040Courtesy of FORD MOTOR CO.

    Is the evenness of spark plug firing voltage greater than 6 kV? 

    Yes No
    INSPECT the spark plug wires for missing cylinders. MEASURE the resistance of the spark plug wires. INSTALL a new spark plug wire if the resistance is greater than 7, 000 ohms per 30.5 cm (1 foot). CHECK for damaged spark plugs or narrow spark plug gaps. MEASURE the resistance of the spark plugs. INSTALL a new spark plugs if the resistance is lower than 2, 000 or higher than 12, 000 ohms. REFER to the service information , Engine Ignition.
    Clear the PCM DTCs. REPEAT the self-test.    		 GO to PINPOINT TEST Z .
  10. JC10 CHECK FOR SPARK AT ALL CYLINDERS 
    • Ignition OFF.
    • Disconnect the spark plug wires from the spark plugs.
    • Connect the Adjustable Ignition Spark Tester THX458 or equivalent to a spark plug wire.
    • Check for spark while cranking the engine.

    Is the bluish-white spark present? 

    Yes No
    GO to  JC12. INSPECT the spark plug wires for missing cylinders. MEASURE the resistance of the spark plug wires. INSTALL a new spark plug wires, if the resistance is greater than 7, 000 ohms per 30.5 cm (1 foot). REFER to the service information , Engine Ignition.
    If the spark plug wires are OK,
    GO to JC11  .
  11. JC11 CHECK THE SECONDARY COIL RESISTANCE FOR THE MISSING CYLINDERS 
    NOTE: Two adjacent coil towers share a common coil and are called a matched pair. The matched pairs are 1 and 4, and 2 and 3.
    • Ignition OFF.
    • Ignition coil pack disconnected.
    • Disconnect spark plug wires from the coil pack.
    • Measure the resistance of each matched pair.

    Is the resistance between 8, 000 and 9, 600 ohms? 

    Yes No
    GO to PINPOINT TEST Z . INSTALL a new ignition coil pack. REFER to the service information , Engine Ignition.
    Clear the PCM DTCs. REPEAT the self-test.
  12. JC12 CHECK THE SPARK PLUGS 
    • Ignition OFF.
    • Check for damaged spark plugs or narrow spark plug gaps.

    Are the plugs OK? 

    Yes No
    GO to JC13  . REPAIR the spark plugs. ADJUST the gap or INSTALL a new spark plugs as necessary. REFER to the service information , Engine Ignition.
    Clear the PCM DTCs. REPEAT the self-test.
  13. JC13 CHECK THE SPARK PLUG RESISTANCE 
    • Measure the spark plug resistance.

    Is the resistance between 2, 000 and 20, 000 ohms? 

    Yes No
    GO to PINPOINT TEST Z . INSTALL a new spark plugs. REFER to the service information , Engine Ignition.
    Clear the PCM DTCs. REPEAT the self-test.
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