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Bad Vapor Canister Purge Valve Symptoms & Replacement Cost

May 16, 2017 | Engine Info

There are over 150 chemicals in the gasoline we pump into our vehicles for fuel. Some of these chemicals may include toluene and benzene; possibly a little bit of lead too. When these chemicals are inhaled, a person can experience symptoms of dizziness, headaches, and difficulty breathing. If you end up inhaling the fumes of these chemicals for a long period of time, it may even kill you. And if that’s not bad enough, air pollution and smog are caused by evaporated gas as well. That is why new legal requirements require auto manufacturers to integrate special technology into their cars which reduce gasoline vapors.

How Vapor Canister Purge Valve Works

The Evaporative Emission Control system of a car contains a purge valve that is normally found between the intake manifold and containment canister that stores fuel vapor; both of which are in the vacuum line. You can operate the purge valve through the vacuum or you can do it electrically. To get those fuel vapors out of the containment canister and into the intake manifold, the purge valve has to open at the right time, which it is made to do. After the vapors enter the intake manifold, they burn up.

Most vehicles these days have a computer in their engine which controls the purge valve, also known as the electrically-operated solenoid valve. This purge valve will close whenever you turn the engine off. When you turn the engine on and let it run for a few minutes, the computer of the engine will electronically communicate with the purge valve and command it to open up gradually. As this happens, fuel vapor that is stored in the canister will be moved to the engine where it will burn up during the combustion process. There are many sensors within the engine which manage the purge flow and allow the engine to determine when the purge valve should open. If there is too much or too little purge flow under a particular condition, then the “Check Engine” light will illuminate on the vehicle’s dashboard to let you know that something is wrong.

Bad Vapor Canister Purge Valve Symptoms

  1. Car Idling (or Rough Idle)

When there is a problem with the purge valve or containment canister, you will notice that your car is idling below a speed that is normal. This is called a rough idle. If the purge valve or canister were to fail altogether and then stick out in the open, then a vacuum leak will form. This will have a grave impact on the quality and speed of the engine idle. Also, if damage were to happen to the solenoid valve or any of its hoses connected to it, then a vacuum leak will form as well.

  1. Trouble Starting

If you have trouble starting your car, then this could be another sign that you have a bad purge valve or containment canister. Just like before, a vacuum leak may form and this will make it even more difficult to start your vehicle. Not only that, a leaky vacuum won’t be able to prevent unmetered air from the outside from getting into the engine. This will ultimately cause problems with the air to fuel ratio. Then, the performance of your vehicle will be in jeopardy.

  1. “Check Engine” Light Illuminates on Dashboard

Finally, the Check Engine light will illuminate on the dashboard if the purge valve is damaged. The engine’s computer will be able to tell when this valve is damaged because its sensors won’t be able to pick up the signal from there that it normally does. Once that happens, the computer turns on the Check Engine light so that you will know there is a problem somewhere in the engine. Of course, there are many reasons why a Check Engine light will turn on. You won’t know the true reason for it turning on until you investigate the engine or have a mechanic do it. They will be able to scan your car for specific trouble codes that will help them identify what the real problem is.

Read also: Bad Camshaft Position Sensor Symptoms & Replacement Cost

Vapor Canister Purge Valve Replacement Cost

To purchase a new purge valve for the purpose of replacing your old one, you can expect to pay anywhere from $120 to $167 in total. The parts will cost you from $76 to $111, while the labor costs will be anywhere from $44 to $56. Then, of course, there are fees and taxes added on to this price too.

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