2007 Mazda 6 MazdaspeedFACTORY OEM SERVICE PROCEDURE

No. 30 Spark Plug Condition: Notes

POSSIBLE CAUSES DESCRIPTIONS

30 SPARK PLUG CONDITION
DESCRIPTION  Incorrect spark plug condition
POSSIBLE CAUSE 
NOTE:
  • Inspecting the condition of the spark plugs can determine whether a problem is related to a specific cylinder or possibly all cylinders.
Wet/carbon stuck on specific plug: 
  • Spark-Weak, not visible
  • Air/fuel mixture-Excessive fuel injection volume
  • Compression-No compression, low compression
  • Malfunctioning spark plug
Grayish white with specific plug: 
  • Air/fuel mixture-Insufficient fuel injection volume
  • Malfunctioning spark plug
Wet/carbon is stuck on all plugs: 
  • Spark-Spark weak
  • Air/fuel mixture-Too rich
  • Compression-Low compression
  • Clogging in intake/exhaust system
Grayish white with all plugs: 
  • Air/fuel mixture-Too lean
    WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system:
    • Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.
    • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this manual.

      (See BEFORE REPAIR PROCEDURE ).

      (See AFTER REPAIR PROCEDURE ).

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    When to See a Mechanic

    Stop DIY work and contact a certified mechanic immediately if any of the following apply:

    • • You smell fuel, burning insulation, or see smoke.
    • • Brakes feel soft, pull hard to one side, or make grinding noises.
    • • The engine overheats, stalls repeatedly, or misfires under load.
    • • You are missing required tools, torque specs, or safe lifting equipment.
    • • You are not confident in the next step or safety outcome.