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Ignition System: Inspection

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.

Check the electrode.
1. Using a megaohmmeter, measure the insulation resistance.
  Correct insulation resistance:
  
  10 MΩ or higher
  
  If the resistance is less then the specified value, proceed to step (b).
  
  HINT:
  
  If a megaohmmeter is not available, perform the following simple inspection instead.
Fig 1: Measuring Insulation Resistance
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Alternative inspection method:

Quickly accelerate the engine to 4,000 rpm 5 times.
Remove the spark plug.

Visually check the spark plug.

Fig 2: Identifying Spark Plug Electrode

G04962918

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Result

ELECTRODE CONDITION RESULT REFERENCE

Electrode condition	Next step
Dry	Go to next step
Wet	Proceed to step (c)

Reinstall the spark plug.

Check the spark plug for any damage to its threads and insulator.

If there is any damage, replace the spark plug.

Recommended spark plug:

SPARK PLUG REFERENCE CHART

DENSO made	SK20R11
NGK made	IFR6A11

Fig 3: Identifying Spark Plug

G04962919

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check the spark plug electrode gap.
Maximum electrode gap for used spark plug:

1.3 mm (0.051 in.)

If the gap is greater than the maximum, replace the spark plug.

Correct electrode gap for new spark plug:

1.0 to 1.1 mm (0.039 to 0.043 in.)

Fig 4: Checking Spark Plug Electrode Gap
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Clean the spark plugs.
If the electrode has traces of wet carbon, clean the electrode with a spark plug cleaner and then dry it.

Air pressure:

Blow 588 kPa (6 kgf/cm ² , 85 psi)

Duration:

20 seconds or less

HINT:

If there are traces of oil, remove them with gasoline before using the spark plug cleaner.

Fig 5: Cleaning Spark Plugs

G04962921

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002