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im new at engine diagnostic what exactly is severe detonation?the truck passed ca smog easy and like a week later it just started making a scratching noise which was the rod bearings.



detonation is an explosion which is not what you want/need in a gasoline engine, what you want is a fast burn.

think of it this way it's the difference between pushing on something or punching it. if you were going shopping you would push the cart not punch it. detonation can be caused by many things or a combination of things and it will damage an engine if left uncorrected.