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No. 30 Spark Plug Condition: Notes

SPARK PLUG CONDITION POSSIBLE CAUSE DESCRIPTION

30  Spark plug condition 
DESCRIPTION 
  • Incorrect spark plug condition.
POSSIBLE CAUSE 
NOTE:
  • Inspecting spark plugs' condition can determine whether problem is related to a specific cylinder or to all cylinders.

Wet/carbon is stuck on specific plug: 

  • Spark-Weak, not visible.
  • Air/fuel mixture-Excessive fuel injection volume.
  • Compression-No compression, low compression.
  • Faulty spark plug.

Grayish white with specific plug: 

  • Air/fuel mixture-Insufficient fuel injection volume.
  • Faulty spark plug.

Wet/carbon stuck on all plugs: 

  • 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 performing the fuel system services:
  • 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 file.

(See  BEFORE REPAIR PROCEDURE  .) 

(See  AFTER REPAIR PROCEDURE  .)