What Are the Symptoms of Spark Plug Failure?

[LenaMarie]

Spark plug failure manifests in the following symptoms: Difficulty in starting the car, both during cold starts and hot starts, often requiring multiple attempts. Engine shaking, noticeable vibrations while driving. Reduced power, a significant decrease in performance compared to normal conditions. Increased fuel consumption. Engine stalling. Failed emissions tests. Common causes and diagnostics of spark plug failure: Several conditions can lead to spark plug malfunction: Incorrect spark plug gap adjustment. A gap that is too small limits the contact area between the spark and the air-fuel mixture, while also suppressing flame kernel growth due to the quenching effect of the electrodes. This results in weak sparks and difficulty igniting the mixture. Conversely, a gap that is too large may exceed the ignition system's voltage capacity, preventing sparking. Cracked spark plug insulator. High-voltage current leaks through the crack, preventing sparking at the electrodes. Electrode carbon buildup, causing current leakage from the center electrode to the surroundings instead of jumping to the side electrode. Excessive carbon deposits can short-circuit the spark plug, preventing sparking and damaging the insulator. Damaged electrodes. Prolonged electrical erosion from sparks or chemical corrosion from combustion gases can cause electrodes to break or detach, rendering the spark plug ineffective. 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 high-voltage wires. Leakage in the wire from the ignition coil to the distributor prevents the entire engine from starting, while leakage in the wire from the distributor to a spark plug affects only that cylinder. Eroded contact points in the distributor. This can prevent all spark plugs from firing, making the engine unable to start or run properly. Spark plug failure requires timely replacement. The replacement steps are as follows: Open the hood and remove the engine's plastic cover. 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 area is free of debris like leaves or dust before proceeding. Insert the new spark plug into the hole, hand-tightening it before using the socket for final tightening. Reattach the high-voltage wires in the correct firing order and replace the cover. Replacement interval: Under normal maintenance conditions, spark plugs should be replaced every 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so consult the owner's manual for specific recommendations.