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故障现象一辆2007年产的皇冠2.5 L轿车来店维护时,客户要求顺便检修一下发动机工作抖动,急加速有异响的故障。故障诊断首先确认故障现象。发动机起动时无异常,急加速有“咯咯”响声。打开发动机室盖后,怠速过程中进气管部位有“嗤嗤”的类似于放气的声音,频率比较高;怠速时发动机有轻微抖动,但不是很明显;仪表盘上的发动机故障指示灯不亮。接着根据由表及里的原则确认异响部位。发动怠速时机用听诊器听诊,进气管处响声比较明显,在气门室盖处没有发现明显异常。根据此现象,找了一个正常的进气管予以更换试验,但是故障依旧。于是继续查找发动机抖动的原因。
Symptoms A 2007 crown 2.5 L sedan to shop maintenance, the customer asked the way overhaul engine work jitter, rapid acceleration abnormal sound failure. Troubleshooting First confirm the symptoms. No abnormality when starting the engine, rapid acceleration, “giggle” sound. After opening the engine compartment cover, the intake pipe part in the idle process has a sound like “deflated” with relatively high frequency; the engine has slight jerk at idle, but it is not obvious; the engine fault indication on the dashboard light is not on. Then according to the principle of the table to confirm the site of abnormal sound. Launch idling timing Stethoscope auscultation, the sound of the intake pipe at the more obvious, at the valve chamber lid found no significant abnormalities. According to this phenomenon, find a normal intake pipe to be replaced test, but the fault still. So continue to find the cause of the engine jitter.