Vibe FWD L4-2.4L (2009)
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Inspect the insulator (2) for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes (3, 4).
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Inspect for evidence of improper arcing.
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Measure the gap between the center electrode (4) and the side electrode (3) terminals. Refer to Ignition System Specifications (See:
Powertrain Management/Ignition System/Specifications). An excessively wide electrode gap can prevent correct spark plug operation.
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Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode (4).
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Inspect for a broken or worn side electrode (3).
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Inspect for bridged electrodes (3, 4). Deposits on the electrodes (3, 4) reduce or eliminates the gap.
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Inspect for worn or missing platinum pads on the electrodes (3, 4), if equipped.
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Inspect for excessive fouling.
Spark Plug Visual Inspection
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Normal Spark Plug Operation
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Results in brown to grayish tan deposits on the area of the spark plug that enters the cylinder.
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A small amount of reddish brown, yellow, and white powdery residue may also be present on the insulator tip around the center electrode.
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These deposits are normal combustion by-product of fuels and lubricating oils which contain additives.
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Carbon Fouling
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Indicated by dry carbon deposits on the portion of the spark plug inside of the cylinder.
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Excessive idling and driving at slower speeds under light engine loads can keep the spark plug temperatures so low that these deposits are not
burned off.
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Rich fuels or poor ignition system output may cause carbon fouling.
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A spark plug of the incorrect heat range may cause carbon fouling.
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Carbon deposits on the spark plug insulator tip may become conductive and cause the high voltage arc to track along the tip to some point
where the high voltage arcs to join the spark plug shell. This arc ignites the air fuel mixture later than normal which, in effect, retards the
ignition timing.
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Heavy carbon deposits may be conductive to the extent that the arc path now becomes a shunt path to the spark plug shell, which prevents the
spark from igniting the air/fuel mixture.
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A power and fuel loss results.
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The spark plug may be permanently damaged by arc tracking and must be replaced.
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Oil Fouling
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Oil fouling appears as wet oily deposits on the portion of the spark plug inside of the cylinder.
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Oil getting past worn piston rings can leave oil deposits on the spark plug.
