故障现象一辆五十铃小货车,装备五十铃4JB1-T1发动机,累计行驶5万km;因发动机窜气、烧机油严重,进行了发动机大修,发动机大修后使用不到一个月,发动机怠速运转时出现清脆异响声,而中高速时异响减弱或消失。故障诊断与排除根据发动机怠速时异响清脆,中高速时异响消失,异响声不连贯,而且无窜气的症状,排除了发动机拉缸的可能。在发动机怠速状态下,采用逐缸断油 Symptom An Isuzu minivan equipped with ISUZU 4JB1-T1 engine had a total mileage of 50,000 km. The engine was overhauled due to engine blow-by and heavy oil burn-in. After overhauling the engine for less than a month, the engine was crisp at idle Abnormal sound, while in high-speed abnormal sound weakened or disappeared. Troubleshooting and troubleshooting According to the engine idling crisp, abnormal sound disappear in high speed, abnormal sound is not coherent, and no flirting symptoms, excluding the possibility of pulling the engine cylinder. In the engine idle state, the use of off-by-cylinder fuel