Vapor Canister Purge Valve Working Principle and Replacement Cost

The vapor canister purge valve works in conjunction with the charcoal canister of a gasoline-powered vehicle. These are parts which exist in the vehicle’s evaporative emission control system. The job of the charcoal canister is to block the fuel vapors from getting out of the gas tank and into the outside environment. This canister will basically store these vapors so that they can be recycled for consumption in the engine.

Working Principle

This is where the vapor canister purge valve comes into play. It is the component of the evaporative emission control system and its main function is to bring those stored vapors into the engine from the charcoal canister. There is a vacuum line that connects the intake manifold with the charcoal canister that contains the fuel vapors. The purge valve lies within the vacuum line to allow these vapors into the intake manifold at the appropriate time. Older vehicles use vacuum operated purge valves while newer vehicles used electronically operated ones.

When the purge valve opens, the fuel vapors can access the intake manifold. From there, the vapors are sent into the internal combustion chamber where they will be ignited with the fuel and air mixture. If you have an electronic purge valve, then the engine control unit manages it. This is the central computer of the vehicle which will calculate the exact amount of vapor that needs to go into the engine. Once it allows enough vapor through, the purge valve will close so that no mater vapor gets through. The vapor will just sit in the charcoal canister until it is needed again.

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Replacement Cost

If you have a bad vapor canister purge valve, you will experience rough idling and problems starting your vehicle. You should see your Check Engine warning light illuminate on the dashboard once this happens. The result will be weaker gas mileage, which means you will need to pay for gas more frequently. At this point, you need to replace your purge valve to fix this problem.

The replacement cost of a vapor canister purge valve will be between $130 to $230 on average. The replacement job itself will not take that long for the mechanic to do, so you are only looking at a cost of between $50 and $100 for the labor. If you can find a mechanic with low hourly rates, then the labor costs will be even cheaper. The main expense will be for the part itself, which should cost around $75 to $120. Therefore, this should be an affordable and convenient part to replace in your vehicle.

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