Mazda MX-5 NA silhouetteMX-5 NA

IGNITION SYSTEM — SPARK PLUG

G-20prose procedure
Continued from G-19

Ignition timing (continued)

  1. 11
    Increase the engine speed and verify that the ignition timing advances.
    Close-up of crankshaft pulley timing-mark area with the timing belt cover scale (continuation from previous page — verifying ignition timing advances).
    05U0GX-043

SPARK PLUG

Removal / Installaion

Note the following points:

Spark plug removal / installation

  1. 1
    When the high-tension lead is to be pulled off, be sure to pull on the boot, not the wire.
    Illustration demonstrating correct removal of a high-tension lead: pull on the boot (right hand), not the wire (left hand shown with X). Left X-mark shows incorrect grip on the lead itself.
    05U0GX-044
  2. 2
    Apply anti-seize compound or molybdenum-based lubricant to the spark plug threads before installing.
  3. 3
    Tighten the spark plugs to the specified torque. Tightening torque: 15—23 N·m (1.5—2.3 m-kg, 11—17 ft-lb)

Spark test

  1. 1
    Disconnect the high-tension lead from the spark plug.
  2. 2
    Connect a new spark plug to the high-tension lead.
  3. 3
    Hold with insulated pliers approx. 5—10mm (0.20—0.39 in) from a ground.
    Spark test setup: high-tension lead connected to a new spark plug held with insulated pliers approx. 5–10 mm from a ground point on the engine, while cranking.
    05U0GX-045
  4. 4
    Crank the engine and verify that a strong blue spark is visible.

Inspection

Check the following and replace the spark plugs as necessary.

Spark plug inspection

  1. 1
    Damaged insulation.
  2. 2
    Worn electrodes.
  3. 3
    Carbon deposits. If cleaning is necessary, use a plug cleaner or a wire brush. Wipe upper insulator.
  4. 4
    Damaged gasket.
Tightening torque (spark plug)
15 - 23N·m
Plug gap
1.0—1.1 (0.039—0.043)mm (in)
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