What does it mean when the CPV valve is stuck in the open position?
2 Answers
Not CPV valve, it should be PVC valve, which means the car PVC valve is stuck in the open position. Here is some information about the car PVC valve: Composition: The car PVC valve is a device on the forced ventilation system of the car engine's crankcase, consisting of a valve body, valve, valve cover, and spring. Function: It directs the gas in the crankcase into the intake manifold through the PCV valve, and a small amount of air enters the intake manifold directly from the air filter through the PCV valve. This prevents icing at the throttle, incomplete combustion, and worsening emissions. It also prevents blow-by gases from entering the atmosphere and prevents engine oil from deteriorating.
The CPV valve stuck in the open position means that the evaporative emission valve in the car is jammed and remains open, unable to close, allowing fuel vapors from the gas tank to directly enter the engine for combustion. When this part fails, you might notice severe engine shaking at idle, unstable RPM, or even the sudden illumination of the check engine light. Over time, fuel consumption tends to increase, emissions exceed standards, and passing annual inspections becomes problematic. I experienced a similar issue with my old car before—the mechanic suggested that the valve might be clogged with dust or rusted due to aging, advising me to get it checked immediately to avoid damaging internal engine components. It's best not to delay repairs, as keeping it open continuously affects the engine's air-fuel mixture ratio, worsening driving performance and leading to higher repair costs. To determine if it's stuck open, you can start the car and listen for unusual engine noises or observe changes in dashboard warning lights.
