Bad Purge Valve Solenoid Symptoms – How To Diagnose This Problem?

So, you have been experiencing some rough idle symptoms lately with your vehicle like rough idle and poor engine performance? And you thinking that your EVAP system is not doing its job properly? In this case, you are probably having bad purge valve solenoid symptoms.

• What Is An EVAP System?
• How To Find The Purge Valve Solenoid?
• Bad Purge Valve Solenoid Symptoms
• Diagnosing A Bad Purge Valve
• Replacing A Bad Purge Valve
• Cost To Replace The Purge Valve
• Conclusion

Most of the modern cars these days have an EVAP system that is collecting all those harmful gasses from escaping into the atmosphere. Thus, keeping the environment safe and without a lot of toxic pollutants flying into the air and damaging the environment.

In the past, there was smog everywhere. Almost every bigger city was suffocating in gasses. But fortunately, some smart people have invented the emission standards and implemented an EVAP system that is helping to keep those harmful gasses trapped inside a charcoal container or they are burned inside of the engine.

But this system tends to fail and develop bad purge valve solenoid symptoms. The purge valve solenoid is one of the most important pieces in this system and it tends to fail sometimes and cause headaches. But you shouldn’t worry, that’s why we are here to help you out solving your problems.

In this article, we are going to learn everything you need to know. What is an EVAP system, how does it work? What are the bad purge valve solenoid symptoms and how to tackle them in a speedy manner? Then we are going to discuss how to diagnose a bad purge valve solenoid and how to replace a bad purge valve solenoid. And lastly, we are going to cover the costs when it comes to replacing. So, let’s begin.

What Is An EVAP System And How Does It Work?

The EVAP system was specifically designed to tackle emissions. These emissions were caused by toxic fumes that are created in the fuel tank.

Basically, when you pour fuel into your tank there are a number of toxic elements that evaporate from the fuel and cause some harmful consequences for the environment. Some of these toxic fumes are creating smog and some of them are even deadly to people and cause a number of diseases that attack the body.

That’s why in the 70s there were imposed some new rules when it comes to emission standards in order to eliminate the smog from the cities and reduce the damage to the environment and the people.

These standards have introduced the EVAP system. The EVAP system is a simple system that works effectively in removing toxins that are usually released into the atmosphere.

This system basically creates pressure in the fuel tank and collects the toxic materials that evaporate. Then these toxic fumes are driven into a charcoal canister.

This charcoal canister has active charcoal that is catching harmful particles and then it releases cleaner fumes into the engine. These fumes are still toxic and are usually driven inside of the combustion process to burn off.

The purge solenoid is the one that allows these fumes from the charcoal canister to pass into the engine. And it does that when there the conditions are met. If your purge valve is stuck open it means that the EVAP system is not working properly and causing some bad purge valve solenoid symptoms.

These bad purge valve solenoid symptoms are really annoying and can affect your driving and the work of the engine. That’s why we are going to help you out and tell you all of the bad purge valve solenoid symptoms in the next chapter.

How To Find The Purge Valve Solenoid?

For beginners, it can be a little bit tricky to locate the purge valve. Since the engine is made out of complex piping that it can easily make you confused and start to give up.

The solenoid is basically a component that is mounted to the wiring harness on one side and on the left and right is connected with piping.

The gasses are collected on one side of the purge valve. And then when the conditions are met and there is enough pressure the solenoid opens to release the fumes inside of the engine.

In most cases when this purge valve fails. It lets the fumes enter the engine freely without any obstacles and this work develops bad purge valve solenoid symptoms in your engine.

That’s why this problem has to be repaired as soon as possible in order to return your engine in proper working order.

The solenoid as we said is mounted to the harness at some point because it needs to receive power. This solenoid is usually mounted on the top of the engine. Somewhere close to the throttle body.

Try to follow the piping and see where the lines go and make a connection with the electrical system.

Also, if you are having some trouble with finding this purge valve. It is useful to google your engine name and then after the engine name type purge valve solenoid location. Then you will probably have some results that are going to help you out in locating the malfunctioned valve and replace it. But before discussing the replacement process let’s first see which are the bad purge valve solenoid symptoms that usually develop.

Bad Purge Valve Solenoid Symptoms

Like with every other component, so the purge solenoid when it goes bad it causes bad purge valve solenoid symptoms. These symptoms are less noticeable, but if you notice them, you will probably get annoyed by them and you will want to fix your bad purge valve as soon as possible. So, let’s start with the bad purge valve solenoid symptoms and dissect them one by one. In order for you to have a clear understanding about these problems and how to tackle them in a speedy manner.

1. Engine Down On Power
2. Rough Idle
3. Rough Idle After Fill Up
4. Check Engine Light
5. Bad Fuel Economy
6. Bad Emissions
7. Hissing Sounds

1. Engine Down On Power

One of the first symptoms that is going to show when you are having a bad purge valve is the reduced engine power. This is because the PCM does not read the same values.

Since there is an increase in the flow of gasses inside of the engine the fuel to air mixture will be completely off and the engine in order to protect itself it’s going to reduce the power output.

This loss of power is going to be noticeable when you start the car. The PCM is smart enough not to let too much air to fuel mixture inside of the combustion process and damage some of the cylinders.

When you are having one of these bad purge valve solenoid symptoms. The best thing to do is to further investigate the issue and find the real culprit. This can be tricky, but if you have also one of the following symptoms as well it’s not that difficult to do.

2. Rough Idle

Rough Idle is another symptom that relates to a bad purge valve. If your car idles badly you are going to notice how the tachometer needle goes up and down all the time.

In worst case scenario the car will shut down because it cannot keep the RPM stable. This can also be connected with a bad throttle body, but you shouldn’t worry and apply more gas on the throttle.

This rough idle is caused by the same wrong fuel to air mixture. Basically, in your engine, there is too much air that is messing up the internal combustion process and it doesn’t help the engine to keep it stable.

3. Rough Engine Work After Filling Up The Tank

Rough engine work when the car starts after fill up is also one of the bad purge valve solenoid symptoms. This is the case because, when you pour new fuel there are fumes that evaporate into the fuel tank. And these gasses then travel into the charcoal canister.

Then after the charcoal canister, they are reaching the purge valve. And if the valve is not closed, as it should be when the car starts. It will drive too much oxygen and gasses inside the combustion process. These gasses cause rough idle and rough engine work during the first few miles until the engine burns all of these fumes and gets used to this strange situation that the overflow of fumes is causing to it.

4. Check Engine Light

Check engine light is one of the symptoms that appear when you are having a bad purge valve solenoid. This check engine light is going to show and you will have to investigate the issue.

A check engine light doesn’t mean a lot without further investigation. You can’t know why is there unless you scan the car for codes. And for this, you are going to need an OBD2 scanner in order to diagnose the issue and make a proper conclusion in order to solve this problem.

Connect your ODB2 scanner in the port and scan the car for errors. If there are any, you can look for them online and see what do they mean. Or if you are having a more advanced scanner, it is going to tell you right away your problem.

If the errors are for your EVAP system, then you will need to further diagnose the issue and remove the solenoid and start some bench tests on it. And how you can perform these tests we are going to explain later in this article. Even though these solenoids are cheap it is a good idea to test the solenoid and see if it’s good or not.

5. Bad Fuel Economy

Bad fuel economy is another bar purge valve solenoid symptom. This is because when there are too much fumes. The engine senses the increased oxygen presence among the gasses and dumps more fuel into the combustion process.

More fuel dumped into the engine means more fuel spent and more frequent visits to the gas station. In order to avoid this problem, you should notice when the car is wasting too much fuel and try to diagnose the issue.

Bad fuel economy can be caused by other things as well. But in order to investigate this problem, you are going to need to perform some scans of the car computer and look for codes.

6. Failing The Emissions Requirements

If your vehicle does not have a properly functioning EVAP system, you are very likely that you are going to fail the emission test in your state.

The person that is carrying out the emission testing at your local car registration center will notice that your car does not make the values that are required for your vehicle and the system is not working properly.

Since the system is not working properly you are going to fail the emissions test. Failing the emissions test is going to cost you and you will have to take your car back another time and this time you need to bring your vehicle with a proper working EVAP system in order to get the vehicle registered.

7. Hissing Sounds

One of the bad purge valve solenoid symptoms are the hissing sounds. This is most notable if the solenoid is stuck open and a lot of pressure is building on the side where the charcoal canister is located.

Since the gasses are not flowing properly, some holes in the vacuum lines can be created and the gasses will start to escape. These hissing sounds are a clear sign that you are having a vacuum leak.

Since you have a vacuum leak, it is a good idea to investigate where this leak is coming from.

You can do this with soapy water. Spray the lines with soapy water and see if there is bubbling. If bubbles are starting to develop that means that you are having a vacuum leak. And if this leak is developed before the purge valve solenoid, it is clear that the solenoid is stuck in the closed position and has to be checked in order to bring the car in proper working order.

And how to diagnose a bad purge valve solenoid? Well, we are going to cover that in the next chapter in detail.

Diagnosing A Bad Purge Valve Solenoid

When it comes to diagnosing a bad purge valve solenoid there are two methods. One of the methods is extremely simple, while the other method is going to require some tooling. These testing practices are necessary to acknowledge if the solenoid is the one that is bad or you are having some other issue with your EVAP system. There are also some other EVAP problems that can appear, but more on them we are going to cover in some of our future articles. Now let’s see how you can test a bad purge valve solenoid.

Basic Method

The basic method involves testing the solenoid if its closed and if it creates a vacuum. This method will only help if you are suspecting that your solenoid is stuck in an open position and it doesn’t interrupt the fumes that are going in and out of the solenoid.

In order to test this issue, you will have to remove the purge valve solenoid and blow with your mouth from one side. If there is an obstruction and you can’t blow it means that your solenoid is closed as it should be. But what about if it’s open? Well, we are going to discuss that next.

Advanced Method

The more advanced method involves testing the solenoid and its ability to open and close. For this method, you are going to need a vacuum tester. You have to connect the vacuum tester on the side from which the gasses are flowing from the charcoal canister.

Then connect the purge valve solenoid with 12V of power. And if the purge valve solenoid works, it’s going to instantly open and allow the air to pass through. If it doesn’t open. You will have to replace the solenoid with a new one. And we are going to explain that next.

Replacing A Bad Purge Valve Solenoid DIY?

We have covered all the bad purge valve solenoid symptoms and how you can bench test a bad solenoid. Now let’s discuss how you can replace this purge valve by yourself with no tools at all at home.

Replacing a bad purge valve solenoid is dead easy. You only need to unplug the old solenoid and mount the new solenoid to the EVAP system. Easy as that.

After installing the new unit, you have to delete all the codes that were caused by the old damaged solenoid. After this, you are good to go. Your car will work perfectly well and you should not have to worry about it anymore.

Cost To Replace A Bad Purge Valve Solenoid

A new purge solenoid is an extremely cheap part. It usually costs between $18 and $50. Depending on the make and model that you are driving.

These parts can be found in almost every parts store all over the country. They can be also found online in stores like eBay and Amazon.

Conclusion

In this article, we have covered everything when it comes to purge valve solenoids. We first learned how the EVAP system works and then we learned where the solenoid is located.

Then we discussed all the bad purge valve solenoid symptoms. In order for you to have a good and clear understanding of this issue and how it can be tackled.

We also described how you can bench test a bad solenoid at home with only a vacuum tool. And lastly, we covered the replacement process and the cost to replace a bad purge valve solenoid.

If you want to learn more about engine problems you can check out our articles on low oil pressure symptoms and front main seal repair cost. Or if you want to learn more about some electrical issues you can check out our articles on bad alternator symptoms and bad starter symptoms.