What are the symptoms of a damaged PVC valve?

[IanFitz]

Here are the symptoms of a damaged PVC valve: 1. Performance impact: After the PVC valve is damaged, it will be unable to control the amount of exhaust gas recirculation. Excessive exhaust gas participating in recirculation will affect the concentration of the air-fuel mixture, potentially causing issues such as difficulty starting, engine shaking, unstable idle, and weak acceleration, all of which impact engine performance. 2. Smoke phenomenon: The PVC valve serves the function of separating oil and gas. When functioning normally, it only draws in exhaust gas and not oil. If the PVC valve is damaged, it will lose its oil-gas separation capability, potentially drawing in oil along with the gas, allowing oil to enter the combustion chamber and resulting in oil burning and blue smoke emission.