What are the signs of a faulty spark plug?
1 Answers
If a spark plug exhibits the following symptoms, it may indicate a fault: Difficulty in starting the car, whether cold or hot, often requiring multiple attempts. Engine shaking, noticeable during driving. Reduced power, with a significant drop in performance compared to normal conditions. Increased fuel consumption. Engine stalling. Failed emissions tests. Common causes and diagnosis of spark plug faults: Several common issues can cause a spark plug 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 voltage provided by the system, preventing sparking. Cracked spark plug skirt. High-voltage current leaks through the crack, preventing sparking at the electrodes. Carbon buildup on the electrodes, causing leakage around the center electrode instead of sparking to the side electrode. Excessive carbon deposits can short-circuit the spark plug, damaging the insulator and rendering it ineffective. Damaged electrodes. Prolonged electrical erosion or chemical corrosion from combustion gases can cause electrodes to break or detach, preventing sparking. Low insulation resistance in the spark plug. This reduces the ignition voltage across the spark gap, weakening or completely eliminating the spark. Short circuit in the high-voltage wire. A leak in the wire from the ignition coil to the distributor prevents the entire engine from starting, while a leak in the wire from the distributor to the spark plug prevents sparking in one cylinder. Eroded platinum contacts. This can cause all spark plugs to fail, preventing engine startup and normal operation. Faulty spark plugs should be replaced promptly. Replacement steps are as follows: Open the hood, remove the engine's 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, checking for and cleaning any external debris like leaves or dust. Insert the new spark plug into the hole, hand-tighten it first, then use the socket to secure it. Reattach the high-voltage wires in the correct firing order and replace the cover. Spark plug replacement interval: Under normal maintenance conditions, replace every 40,000-60,000 kilometers, but this may vary by brand and engine type. Always refer to the owner's manual for guidance.
