What are the symptoms of a constantly open purge valve?
2 Answers
Symptoms of a constantly open purge valve: 1. Increased fuel consumption: When the purge valve remains open, the gasoline vapors adsorbed in the charcoal canister will continuously enter the cylinders for combustion as soon as the engine starts, leading to increased vehicle fuel consumption. 2. Difficulty starting the engine: Since the purge valve is always open, the intake manifold will be filled with gasoline vapors. When the engine starts, the overly rich air-fuel mixture can cause difficulty in starting the engine or even stalling. 3. Increased carbon deposits: The richer air-fuel mixture results in incomplete combustion of gasoline, which easily leads to the accumulation of carbon deposits.
As a frequent DIY car repair novice, I personally experienced the symptoms when the carbon canister purge valve got stuck open, and they were quite obvious. There was always a pungent gasoline smell inside and outside the car, especially after parking—the odor would fill the cabin, making friends frown as soon as they got in. Cold starts were particularly troublesome, with the engine struggling to turn over like it was gasping for breath, and the whole car would shake at idle as if it was about to stall. Fuel consumption shot up—normally, a full tank would last 500 kilometers, but now it barely made it past 400. What’s more annoying was the check engine light constantly staying on, reminding me to get it fixed, but ignoring it could lead to air pollution or even fines. I quickly had a mechanic inspect and replace it, and after a simple swap, everything felt much smoother, and driving became fluid again.
