Ignition System: Inspection

NOTE: In this article, the terms "cold" and "hot" refer to the temperature of the coils. "Cold" means approximately - 10°C(14°F) to 50°C(122°F). "Hot" means approximately 50°C(122°F) to 100°C(212°F).

INSPECT SPARK PLUG
NOTE:
- Do not use a wire brush for cleaning.
- Do not attempt to adjust the electrode gap of a used spark plug.
1. Check the electrode.
  1. Using a megaohmmeter, measure the insulation resistance.
    Correct insulation resistance: 10 MΩ or higher
    
    If the resistance is less than the specified value, proceed to procedure "C".
    
    HINT:
    
    If a megaohmmeter is not available, perform the following simple inspection instead.
    
    Fig 1: Measuring Insulation Resistance
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Alternative inspection method:
  1. Quickly accelerate the engine to 4,000 rpm 5 times.
  2. Remove the spark plugs.
  3. Visually check the spark plugs.
    
    Fig 2: Checking Spark Plug
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    - If the electrode is dry, the spark plug is functioning. Reinstall the spark plug.
    - If the electrode is damp, proceed to procedure "A", "B" and "C".
3. Check the spark plug for any damage to its thread and insulator (Procedure "A").
  If there is damage, replace the spark plug. If not, reinstall the spark plug.
  
  Require spark plug:
  REQUIRE SPARK PLUG
  
  DENSO made FK20HR11
  
  CAUTION: Please use long-reach plug.
4. Clean the spark plugs (Procedure "B"). If the electrode has traces of wet carbon, clean the electrode with a spark plug cleaner and then dry it.
  
  Fig 3: Using Spark Plug Cleaner
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Air pressure:
  
  588 kPa (6 kgf*cm ² , 85 psi)
  
  Duration:
  
  20 seconds or less
  
  HINT:
  
  Only use the spark plug cleaner when the electrode is free of oil. If the electrode has traces of oil, use gasoline to clean off the oil before using the spark plug cleaner.
5. Check the spark plug electrode gap (Procedure "C").
  Electrode gap:
  
  1.0 to 1.1 mm (0.039 to 0.043 in.)
  
  Maximum electrode gap:
  
  1.4 mm (0.055 in.)
  
  If the gap is greater than the maximum, replace the spark 1.0 to 1.1 mm ark plug.
  
  Fig 4: Checking Spark Plug Electrode Gap
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002