What is the reason for abnormal noise during cold start but not when the engine is warm?
1 Answers
The reason for abnormal noise during cold start but not when the engine is warm may be due to severe carbon deposits on the valves or intake manifold. During cold starts, the gasoline sprayed by the fuel injectors is largely absorbed by these carbon deposits, leading to abnormal noise. Below is detailed information about engine carbon deposits: 1. Overview: Engine carbon deposits refer to a coking-like substance formed during engine operation, resulting from unsaturated olefins and gum in fuel under high temperatures. 2. Additional Information: Carbon deposits are also a manifestation of abnormal discharge in spark machining. If the fuel injectors are fouled, the atomization of the sprayed gasoline deteriorates, causing uneven mixing of gasoline and air, which increases the amount of gasoline condensing on the intake valves. All internal combustion engines produce carbon deposits.