If you have tested the purge valve solenoid and it tests bad, it is best to replace it, but in some scenarios, it may not be possible, such as low funds.
A bad purge valve is a common failure in a vehicle’s Evap system.
Often the costs to repair a bad purge valve can be high, and many wonder what happens when driving a vehicle with a bad purge valve.
What is the Purge Valve?
The Evap system feeds gas vapors from the gas tank into the engine so they don’t escape into the atmosphere.
It is a basic valve that opens when the engine is running so gas vapors can go into the engine and be burnt off.
It closes when the engine is off so the gas vapors don’t escape and fill the engine with gas vapors.
What Happens If I Drive with a Bad Purge Valve?
What happens will depend if the valve is stuck open or closed and can vary between manufacturers.
Some vehicles have no changes in performance, and besides the engine light being on, there are no other issues.
The car or truck will not be able to pass an emission test until the system is fixed.
Engine Performance of a Purge Valve Stuck Open
When the purge valve is stuck open, it can cause a vacuum leak to the intake manifold.
A purge valve has two ports, one to the engine intake manifold and the other to the charcoal canister underneath the vehicle.
If the valve is stuck open and never closes, it can cause a vacuum leak which can cause the engine to run badly.
Also, when fueling up, the vapors can be pushed into the engine, which can cause starting problems.
Engine Performance of a Purge Valve Stuck Closed
An engine usually runs better when the purge valve is stuck closed as to being stuck open.
Often there is a gas smell inside the vehicle; since the vapors are backed up and have no place to go, they often seep out.
The engine may also get worse fuel economy.
Many cars and trucks will have little to no performance issues when the purge valve is stuck closed, but results can vary by manufacturer.
Will a Bad Purge Valve Damage an Engine?
No, a bad purge valve will not damage an engine but may cause it to run badly.
The engine may run badly, but there will not be any permanent damage.
How Important is a Purge Valve to an Engine?
A purge valve is a part of emission and is not an important component.
It can cause issues with performance if it is stuck open but is not a critical part of the engine.
Is a Purge Valve Expensive to Fix?
The average cost to replace a purge valve is roughly $150 to $200, but prices can vary on location.
Replacing a purge valve is usually a straightforward task, with many DIY individuals able to replace a unit and save money.
If you do replace a unit yourself, be sure to watch a YouTube video or read one of the many online posts to see the difficulty level.
The results of driving with a bad purge valve can vary based on if the valve is stuck open or closed.
It also can vary based on the manufacturer since all Evap systems have design variations.
When the solenoid is stuck closed, often there is no performance issue.
When the solenoid is stuck open, there can be issues since it causes a vacuum leak to the intake manifold into the Evap system.
If the valve is stuck open, some backyard mechanics will block off the port to the manifold as a temporary fix.
Have you had an engine performance issue when driving with a bad purge valve? Let us know your symptoms below, along with vehicle type.