What Causes the Puttering Sound in a Car Engine?
1 Answers
Car engine puttering sound is caused by: 1. Engine misfire: Engine misfire mainly refers to one or more cylinders of the engine not working properly, typically manifested as: intermittent exhaust gas flow with noticeable pauses, severe shaking of the exhaust pipe, and a clear "puttering" or thumping sound from the engine. This phenomenon is often closely related to ignition coil failure. 2. Overly rich air-fuel mixture: When the engine's air-fuel mixture is too rich, the symptoms include: difficulty starting the engine; poor acceleration after starting, uneven engine operation; black smoke from the exhaust pipe accompanied by a puttering sound, sometimes backfiring; reduced engine power and increased fuel consumption. This is mostly related to carbon buildup and clogged air filters. 3. Cold start: During a cold start, the engine's lubrication is less effective, the engine oil has poor fluidity and is more viscous, leading to mechanical wear noises. Additionally, during a cold start, the coolant temperature is low, and the air-fuel mixture is richer, resulting in incomplete combustion that causes engine vibration and a puttering sound. This is generally normal. It could also be due to excessive carbon buildup in components like the idle air control valve, intake manifold, intake valves, and combustion chamber.
