How to Identify Good or Bad Spark Plugs?

[LailaDella]

Spark plugs exhibit the following symptoms when they may be faulty: Difficulty in starting the car, both during cold starts and hot starts, often requiring multiple ignition attempts. Engine shaking, where the car experiences vibrations while driving. Lack of power during driving, with noticeably reduced performance compared to normal conditions. Increased fuel consumption. Engine stalling. Failed exhaust emissions. Common causes and diagnostics of spark plug failures: Several common issues can cause spark plugs to malfunction: Incorrect spark plug gap adjustment. If the gap is too small, it not only limits the contact area between the spark and the air-fuel mixture but also suppresses flame kernel growth due to the quenching effect of the electrodes. Even if a spark occurs, it will be weak, making it difficult to ignite the mixture. If the gap is too large, the ignition system may not provide sufficient voltage to create a spark between the electrodes. Cracked spark plug skirt. High-voltage current may leak through the crack, preventing the spark from jumping between the electrodes. Electrode carbon buildup, where the center electrode leaks current to the surroundings instead of jumping to the side electrode. Excessive carbon deposits can short-circuit the spark plug, preventing it from sparking and damaging the insulator. Damaged electrodes. Prolonged electrical erosion from sparks or chemical corrosion from combustion gases can cause the electrodes to break or fall off, preventing sparking. Low insulation resistance of the spark plug. This condition weakens the ignition voltage applied to the spark gap, resulting in a weak spark or complete loss of ignition function. Short circuit in high-voltage wires. If the high-voltage ignition wire from the ignition coil to the distributor leaks, the entire engine may fail to start. If the wire from the distributor to the spark plug leaks, the spark plug in one cylinder may not spark. Burnt platinum contacts. This can cause all spark plugs to fail to spark, preventing the engine from starting or running normally. Faulty spark plugs should be replaced promptly. The replacement steps are as follows: Open the hood, remove the engine's plastic cover, and disconnect the high-voltage wires. Mark each cylinder's position to avoid confusion. Use a spark plug socket to remove the spark plugs one by one. Check for external debris like leaves or dust and clean thoroughly before proceeding. Insert the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to tighten it fully. Reinstall the high-voltage wires in the correct firing order and reattach the cover. Spark plug replacement interval: Under normal maintenance conditions, replace spark plugs every 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type. Always refer to the owner's manual for specific recommendations.