What are the causes of carbon deposits?

[McElliana]

The causes of carbon deposits are: 1. Long-term poor driving habits of the car owner; 2. Mismatch between fuel octane rating and compression ratio; 3. Aging or damage to the engine carburetor; 4. Prolonged high-load driving; 5. Not replacing the air filter; 6. Inaccurate ignition timing or fuel supply timing; 7. Low engine temperature; 8. Poor sealing of valves and valve seat rings; 9. Prolonged engine idling. The parts that need carbon deposit cleaning include: 1. Engine combustion chamber; 2. Intake manifold; 3. Fuel injector; 4. Throttle valve; 5. Spark plug; 6. Three-way catalytic converter. Carbon deposits are coking substances produced by unsaturated olefins and gums in fuel under high temperatures during engine operation.

[KingstonDella]

The reason for carbon buildup is something I often think about while driving, mainly due to incomplete fuel combustion. When using low-quality gasoline, which contains many impurities, the combustion is not clean, leaving behind carbon particles. For example, during short city drives, if the engine isn't fully warmed up before stopping, the combustion efficiency is low, and carbon deposits easily accumulate on the cylinder walls and fuel injectors. Insufficient air supply also worsens the situation—if the air filter is dirty or clogged, there's less oxygen, and the fuel doesn't burn completely. Additionally, poor driving habits, such as frequent low-speed driving or cold starts, accelerate carbon buildup. I recommend using high-quality gasoline, occasionally driving on highways to fully warm up the engine for more complete combustion, or using additives to clean the internals. These steps can reduce carbon formation and keep the car running more smoothly.

[LeNoah]

The sources of carbon deposits are quite diverse, and from a mechanical perspective, they mainly stem from fuel system issues. For instance, when fuel injectors or intake valves become dirty, uneven fuel spraying occurs, leading to uneven temperatures in the combustion chamber. Unburned fuel then deposits as carbon. A malfunctioning air flow sensor may also cause an overly rich air-fuel mixture, resulting in incomplete oxidation and leaving behind black residue. Improper engine temperature control, such as cooling system failures, can lead to excessively high or low cylinder temperatures, both of which induce carbon buildup. I recommend regularly inspecting these components to ensure cleanliness; use the correct engine oil and avoid random choices, as aged oil mixing into the combustion chamber can exacerbate the problem. Timely maintenance plays a significant role in prevention.

[VanEvelyn]

As an average car owner, I've found that carbon buildup is mainly caused by low-quality fuel and driving habits. Cheap gasoline doesn't burn cleanly, leaving residue that accumulates in the engine. Frequent short trips or only driving slowly in the city, where the engine doesn't get hot enough before shutting off, leads to increasing carbon deposits. A clogged air filter exacerbates the problem by reducing airflow. This results in decreased power, increased fuel consumption, and costly, time-consuming repairs. Regularly using cleaning additives or driving on the highway can help mitigate the issue, but choosing good-quality fuel is key.