Spark plug defects (BMW X5 E53)

Analysis of the curve of the maximum value of breakdown voltage at the crankshaft speed in idle mode (Fig. 3.48):

• 1 - normal maximum value of breakdown voltage, spark plug is in good condition;
• 2 - low amplitude of the maximum value of breakdown voltage, small spark gap between the electrodes;
• 3 - high amplitude of the maximum value of breakdown voltage, large spark gap between the electrodes.

Analysis of the spark discharge duration curve at idle crankshaft speed:

• normal spark duration (fig. 3.49,a), the spark plug is OK.

• long spark duration (fig. 3.49,b), small gap between spark plug electrodes.

• reduced spark duration (fig. 3.49,c), large gap between spark plug electrodes.

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