Aiming at the problems that abnormal noise faults of traditional fuel vehicle engines affect driving experience and driving safety, as well as the difficulty in maintenance, this article first classifies and sorts out three common types of abnormal noises related to rotational speed rhythm, load temperature, and local location. Technical difficulties such as low accuracy of reanalysis diagnosis, complex maintenance operations, and limited equipment costs. By establishing a "primary-intermediate-advanced" hierarchical diagnosis system, optimizing the cold knocking cylinder repair and crankshaft main bearing noise treatment technology, and formulating management strategies for lubrication/combustion systems and fasteners, the speed and quality of abnormal noise fault repair can be enhanced. Practice has shown that this scheme can reduce the recurrence rate and occurrence rate of faults, providing support for the maintenance of traditional fuel vehicle engines.