How to Determine the Quality of Spark Plugs?

[Jasmine]

Spark plugs exhibit the following symptoms when they may be faulty: Difficulty starting the car, both during cold starts and hot starts, often requiring multiple attempts. Engine shaking, where the car experiences vibrations while driving. Reduced power, noticeably weaker performance compared to normal conditions. Increased fuel consumption. Stalling issues. Failed exhaust emissions. Common causes and diagnosis of spark plug failures: Several common issues can cause spark plugs to malfunction: Incorrect spark plug gap adjustment. A gap that is too small limits the contact area between the spark and the air-fuel mixture and suppresses flame kernel growth due to the quenching effect of the electrodes, resulting in weak sparks and difficulty igniting the mixture. A gap that is too large may exceed the ignition system's voltage capacity, preventing a spark from jumping between the electrodes. Cracked spark plug skirt. High-voltage current leaks through the crack, preventing sparks from jumping between the electrodes. Carbon buildup on the electrodes, causing leakage from the center electrode to the surrounding area instead of jumping to the side electrode. Excessive carbon deposits can short-circuit the spark plug, preventing sparks and damaging the insulator. Damaged electrodes. Prolonged electrical erosion from sparks or chemical corrosion from combustion gases can cause electrodes to break or detach, preventing sparks. Low insulation resistance of the spark plug. This reduces the ignition voltage applied to the spark gap, weakening or completely disabling the spark. Short circuit in high-voltage wires. Leakage in the wire from the ignition coil to the distributor can prevent the entire engine from starting, while leakage in the wire from the distributor to the spark plug can prevent a single cylinder's spark plug from firing. Eroded platinum contacts. This can cause all spark plugs to fail, preventing the engine from starting or running normally. Faulty spark plugs should be replaced promptly. The replacement steps are as follows: Open the engine hood, remove the plastic cover, and disconnect the high-voltage wires, marking each cylinder's position to avoid confusion. Use a spark plug socket to remove each spark plug, ensuring the surrounding area is free of debris like leaves or dust. Insert the new spark plug into the 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: Typically, spark plugs should be replaced every 40,000-60,000 km under normal maintenance conditions, but this may vary by brand and engine type. Always refer to the owner's manual for specific recommendations.