Check for signs of leakage or cracked surfaces at both ends of tube, exhaust manifold and EGR valve.

检查两个管的末端，排气歧管和EGR阀是否有泄露或表面有裂痕。

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The peak value varies in different fault conditions and it can be used as a characteristic for diagnosing leakage fault of exhaust valve, the fault in initial stages can also be diagnosed.

可以将三阶谱的峰值作为判断气阀是否漏气的一个诊断特征量，同时也为诊断内燃机气阀的早期漏气故障提供了依据。

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Expansion type automatic exhaust valve, no leakage.

膨胀式自动排气阀，不渗漏。

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