Do Spark Plugs Affect the Engine?
2 Answers
Spark plugs have an impact on fuel consumption. If a spark plug is damaged, it can cause the engine to lose power, idle unstably, and most importantly, make ignition difficult, affecting the normal use of the vehicle. Methods to determine if a spark plug is damaged: Remove the spark plug and observe its appearance to assess its condition. A normal spark plug's insulator skirt and electrodes should appear gray-white, gray-yellow, or light brown. A properly functioning spark plug will have a reddish-brown insulator skirt, with an electrode gap between 0.8-0.9mm and no signs of electrode burn. If the spark plug has oil stains or deposits but is not damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged—showing signs of blistering, black streaks, cracks, or melted electrodes—identify the cause of the damage, troubleshoot the issue, and replace the spark plug. Additionally, if the spark plug appears black as if smoked, it indicates the wrong heat range was selected or the air-fuel mixture is too rich, possibly due to oil leakage. Steps for replacing spark plugs: Open the hood, lift the engine's plastic cover, and remove 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. While removing them, check for external debris like leaves or dust and clean thoroughly. Place the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to tighten it further. Reinstall the high-voltage wires in the firing order and secure the cover.
Spark plugs have a significant impact on the engine. Having driven for over 20 years, I deeply understand this. Spark plugs act like the critical ignition switch, responsible for igniting the air-fuel mixture. If they are worn out or heavily carbon-fouled, the car becomes difficult to start, especially on cold winter mornings—sometimes requiring multiple attempts. At idle, the engine may also shake noticeably. For instance, when one of my spark plugs failed recently, the car jerked intermittently while driving, with a clear drop in power and a 20% surge in fuel consumption. Worse yet, long-term neglect can damage internal engine components due to incomplete combustion leading to carbon buildup, potentially harming pistons and cylinders. I recommend inspecting spark plugs at least every 40,000 kilometers or replacing them as per the manual's recommended interval.
