What Causes the Popping Sound in Cars?
1 Answers
Possible causes of the popping sound in cars are as follows: 1. Overly rich air-fuel mixture: When the air-fuel mixture in the engine is too rich and not completely burned, it is expelled with the exhaust. When the unburned mixture enters the exhaust pipe, it encounters combustible air and produces an explosive sound, leading to excessive noise from the exhaust pipe. At low engine speeds, the sound is heavy and unstable, while at high speeds, the exhaust noise may lessen. This is also a key indicator for diagnosing an overly rich mixture causing loud exhaust noise. 2. Excessive fuel level in the float chamber: When the fuel level in the float chamber is too high, it not only causes an overly rich air-fuel mixture but may also result in some fuel entering the cylinder without proper atomization, increasing exhaust noise. If large oil droplets are observed in the exhaust, it indicates an excessively high float chamber fuel level or a faulty float chamber needle valve seal. 3. Insufficient ignition timing: Incorrect engine stroke clearance, improperly sealed valves, or misaligned timing gears causing premature opening of the exhaust valve can lead to loud exhaust noise. Delayed ignition prolongs the combustion time of the air-fuel mixture, resulting in secondary combustion inside the exhaust pipe and increased noise.
