The Real Cause of Engine Knocking?

[SiennaLee]

Below are the causes of engine knocking: 1. Overly advanced ignition timing: To ensure that the piston receives power immediately upon entering the power stroke after the compression stroke, ignition typically occurs before the piston reaches top dead center. However, excessively advanced ignition can cause most of the fuel-air mixture to burn while the piston is still in the compression stroke. The remaining unburned mixture then undergoes extreme pressure and auto-ignites, leading to knocking. 2. Insufficient fuel cleanliness: Physical and chemical impurities in the fuel, including certain aromatic compounds, can also cause auto-ignition during the engine's compression process, resulting in knocking.

[VanEthan]

Let me explain engine knocking from a mechanic's perspective. The root cause is when the fuel-air mixture in the engine combusts spontaneously before the spark plug ignites it, creating that knocking sound. Main contributing factors include using low-quality gasoline with insufficient octane rating that can't withstand high temperature and pressure conditions; or ignition timing being set too early, causing uncoordinated combustion. Other causes are excessive carbon buildup in the engine creating hot spots, or incorrect air-fuel ratio (either too lean or too rich mixture). If this occurs long-term, it can wear out pistons and valves, even damage internal engine components. I recommend regular inspection of the ignition system, carbon deposit cleaning, and always using higher-grade gasoline to effectively prevent knocking. If you hear abnormal sounds while driving, slow down immediately and check - never ignore it, as engine protection is paramount. Always refuel at reputable gas stations and avoid saving money with inferior fuel, which accelerates engine aging.

[LaAnastasia]

I've been driving for over a decade and have encountered engine knocking a few times. It's usually caused by using cheap gasoline with poor quality or low octane rating, leading to premature ignition under high temperatures. Or it could be due to aggressive throttle habits that suddenly increase engine pressure. High summer temperatures or radiator malfunctions causing engine overheating can also trigger knocking more easily. I remember once during a long trip using fuel from an unknown gas station, and I kept hearing popping sounds along the way. After stopping to check, I found it was caused by uneven internal temperatures due to carbon buildup. Now I never fill up at random stations anymore, and I've learned to clean the throttle body every few months. Although knocking seems minor, it can damage engine efficiency and affect driving experience. It's best to have it checked at a repair shop as soon as possible. Don't delay, otherwise fuel consumption will increase, ultimately raising costs. Gently pressing the throttle when starting can also reduce the risk.

[OReid]

Knocking often occurs due to inadequate daily maintenance. From my experience as a car owner, if carbon deposits accumulate or the ignition system is not properly adjusted, knocking sounds are likely to occur during acceleration. Using low-quality fuel is a major cause, as impurities in the fuel affect combustion stability; or improper air-fuel ratio adjustment, making the mixture too lean. To prevent this, I regularly clean engine carbon deposits, check spark plugs and ignition wires, and ensure the cooling system is functioning properly. These minor maintenance tasks can prevent knocking and extend the car's lifespan. Developing good habits, such as only using high-grade gasoline and avoiding prolonged high-load engine operation, can save a lot of trouble. If problems do arise, early inspection and repair are the best course of action.