Bad EGR Valve Symptoms, Causes and How to Clean It

All vehicle drivers want to enjoy an eco-friendly environment inside the vehicle. This eco-friendly environment is only possible if you ensure the proper maintenance and working of the vehicle’s EGR system. The exhaust gas recirculation valve is the most important part of the EGR system. The EGR valve helps to reduce the emission rate of exhaust gases. Driving with a defective or damaged EGR valve is very dangerous for your health, car, and environment. This article mainly explains the bad EGR valve symptoms, causes, and its replacement cost. 

What is an EGR Valve?

The EGR valve is a part of the engine that is used to redirect a specified amount of the exhaust gases back into the combustion chamber instead of discharging them into the environment. All vehicles depend on the EGR valve to control exhaust gas flow.

EGR valves control the chemical and thermal demands of a moving vehicle’s engine. It ensures a smooth operation of the engine running for a long time. Therefore, proper maintenance and repair of the EGR valve are very important.

A faulty valve can lead to multiple problems. The main advantages of these valves are that they lower engine cylinder temperature and lower exhaust emissions.

EGR Valve

In the fuel combustion process, the engine sucks air from the atmosphere and mixes it with the fuel. As the air and fuel mixture starts burning into the combustion chamber, the temperature of the mixture increases, which causes the emission of nitrogen oxides (NOx).

If your car does not have EGR valves, the produced NOx may be exhausted into the atmosphere, which can produce some serious health problems such as cancer, passenger death, etc.

This valve works in combination with the EGR system to achieve the desired targets. As the EGR valve opens, exhaust gas enters the EGR system, which controls the exhaust emission rate.

Symptoms of Bad EGR Valve

The EGR valve is a vital part of the car engine. It helps to control the flow and emission of exhaust gases. In case of exhaust gas recirculation valve failure, you may face many problems related to the vehicle engine and your health.

The following are the symptoms of a bad EGR valve:

  1. Check engine light
  2. The smell of unburnt fuel
  3. Rough idling
  4. A reduction in engine performance
  5. Poor Air-Fuel ratio
  6. Poor fuel economy 
  7. Engine stalls while idling
  8. The smell of unburnt fuel
  9. Failed emissions test
  10. Engine knocking 

1) Poor Engine Performance

The reduction in engine performance is one of the first signs of a bad EGR valve. As your vehicle exhaust valve goes bad, you can see a clear reduction in engine efficiency and reduced accelerator pedal efficiency.

poor engine performance

As you observe a reduction in the performance of your car engine, immediately check your valve. If you can’t check, contact a professional mechanic and repair it.

2) Check Engine Light

The check engine light illumination is also a clear sign of a faulty EGR valve. This light may also appear due to many other reasons. When you drive your vehicle, you should always monitor the engine indicator, which informs you about the health of your engine.

engine warning light due to bad egr valve

As the check engine light turns on, it shows that you most probably have a faulty EGR valve. The powertrain control module (PCM) uses the data of the EGR valves to regulate engine timing and many other functionalities. When it monitors an issue with the EGR valve, it triggers the check engine light to alert the driver.

Read More: Why Is Your Check Engine Light Illuminating?

3) Smell of Unburnt Fuel

If your EGR valve doesn’t work properly, the engine consumes more fuel than usual because it works harder to move the vehicle. In such a case, the temperature of the combustor will be very high, releasing a large number of hydrocarbons. These hydrocarbons are mixed with the increased NOx emissions, creating a hazardous mixture of injurious gases.

NOx emissions from your car’s exhaust pipe are dangerous and have a strong odor.

smell of unburnt fuel

4) Failed Emissions Test

Emission test failure is one of the clear symptoms of a bad EGR valve. The emission test is performed to check the engine exhaust gas emission rate. 

This test can’t precisely check the condition of the EGR, but if the emissions test fails, it is recommended that you contact a specialist to check the vehicle’s EGR valve.

Failed Emissions Test

However, this test can’t let you know the exact health of your EGR, but if the emission test fails then you must immediately contact a professional for the proper inspection of your valve.

5) Rough Idling

If your engine’s EGR valve fails, it may produce rough idling. Rough idling is the most common symptom of a failed or damaged EGR valve.

Rough idle usually occurs when the EGR valve remains stuck in the closed or open condition. This can also represent that an extreme amount of exhaust gases are entering the combustion chamber.

Rough Idling due to bad egr valve

6) Poor Acceleration

acceleration problems

The poor acceleration of the car is one of the major symptoms of a bad EGR valve. As the exhaust valve clogs, it doesn’t open or close properly due to that an excessive amount of exhaust gases start entering the engine. This leads to poor acceleration.

The excess air creates a lean fuel-air mixture inside the combustor without the correct ratio of fuel and air. This issue may lead to misfiring and cause poor acceleration.

7) Engine Knocking

engine knocking due to a faulty EGR valve

If your engine is producing knocking extensively, it may be due to a bad EGR valve. This is because the purpose of the EGR system is to maintain the lower temperature of the engine and prevent it from overheating. As the EGR fails, the engine overheats and it produces knocking.

Read More: Reasons Why Is Your Engine Knocking?

8) Poor Air-Fuel ratio

The imbalanced or poor air/fuel mixture is another sign of a faulty EGR valve that leads to poor fuel efficiency. Your vehicle contains an EGR sensor that monitors the performance of the EGR system. The PCM of your vehicle utilizes the information of this sensor to regulate the air-fuel ratio and engine timing.

When this sensor goes bad, your PCM doesn’t adjust the air-fuel mixture according to the requirements. In such conditions, your engine may consume more fuel than usual.

A poor air-fuel mixture may also lead to misfiring and engine stalling issues.

9) Engine Stalls While Idling

engine Stalling

If the EGR valve is blocked in the open position, the engine starts to generate idling and stalling. The engine stalling is very hazardous while driving. The vehicle stalling may cause a severe accident. Therefore, if your car is stalling because of a bad exhaust valve, then immediately replace the valve with a new one.

Read More: Engine Stalling Causes and Prevention

10) Poor Fuel Economy

The EGR valve also plays a vital role in improving the vehicle’s fuel economy. Therefore, if the valve breaks or clogs, it will not work properly, and fuel consumption will have to increase. This valve recirculates exhaust gases to the vehicle’s engine while maintaining a normal temperature in the combustion chamber.

Poor fuel economy due to a bad EGR valve

In case of bad EGR valves, your vehicle engine may consume more than usual. For example, the average fuel consumption of a car is typically 20 miles per gallon or 9 liters per 80km. If the car’s EGR valve fails, it increases gallons per mile and forces you to consume more money to fuel the vehicle.

Read Also: Different Types of IC Engines

Causes of a Bad EGR Valve 

  • Clogged EGR passages or carbon buildup inside the passages
  • Defective EGR vacuum solenoid
  • Faulty EGR switching valve
  • Age of the valve
  • There may be issues with the EGR vacuum control
  • Blown or leaked EGR valve gasket
  • Leakage in the intake manifold
  • Faulty EGR temperature sensor
  • A faulty or damaged turbocharger
  • Incorrect connection of the vacuum hoses

EGR Valve Location

EGR Valve location

The location of the EGR valve varies according to the vehicle model and engine type. The EGR valve is most commonly located at the engine top. It normally connects to a metal pipe that extends from the exhaust. It makes a connection between the intake manifold and the exhaust manifold.

How to Clean an EGR Valve

If you want to clean your EGR system, follow the below-given steps to clean an EGR valve:

  • First of all, put the car on a flat and leveled surface, as well as the car must be in a “park” position. Turn on all the brakes of your car.
  • Turn off the engine of the car. Disconnect the cable from the negative terminal of the battery.
  • Check whether you have an electrically or mechanically controlled EGR valve. This is most commonly mentioned in the EGR valve repair or manufacturer manual.
  • Eliminate the bolts of the valve and all other blocking parts to the valve.
  • During the elimination process of the EGR valve, ensure that it must come out with a gasket. If you observe bad gasket symptoms on your gasket, replace it with a new one.
  • Remove all electrical connections that are connected to the valve.
  • Wear Personal Protective Equipment (PPE) such as safety glasses and gloves for your safety.
  • After wearing PPEs, start the cleaning process.
  • Spray EGR valve cleaner inside the valve. Keep spraying until the carbon layer is fully detached from the valve and only the cleaning fluid starts coming out.
  • Use a blunt scraper and a pipe-cleaning brush to eliminate carbon collection.
  • Repeat this process until the full removal of the carbon deposits.
  • Use a clean cloth to wipe the valve surface.
  • If you have difficulty in cleaning the valve with a pipe cleaning brush, soak the valve in the cleaning solution for some time.
  • Repeat the brushing process again after soaking.
  • Reinstall the valve with a new gasket. Unscrew the screws and reconnect the electrical parts and vacuum.
  • Reconnect the negative terminal of the battery.
  • Turn on the engine and make sure the engine lights are off.

EGR Valve Replacement Cost

The average replacement costs of the EGR valve vary according to the region where you live and the type of brand.

The average replacement cost of the EGR valve is from $220 to $370. In this cost, the EGR valve itself cost is from $170 to $280. If you are not replacing it yourself and hiring labor, the labor cost varies from $55 to $90.

Average Cost$220 – $370
Valve Parts Replacement Cost$170 – $280
Labor Cost$55 – $90

How do you know it is time to clean EGR Valve?

Following are some signs that tell you that your EGR valve needs cleaning or replacement:

  • Reduction in engine efficiency
  • Reduction in gas mileage
  • The smell of unburned gas fumes
  • Engine ‘ping’ when under load
  • Engine overheating
  • Poor engine performance during the drive
  • Engine vibration
  • Rough idle
  • Problems in starting the engine

FAQ Section

What is the function of the EGR valve?

The EGR valve is used to recirculate a précised amount of NOx back into the engine cylinder. It connects the intake manifold to the exhaust manifold and controls the exhaust emissions. It permits a precise amount of exhaust gases to be reintroduced into the combustion chamber.

What are the signs of a Bad EGR Valve?

  • Check engine light
  • The smell of unburnt fuel
  • Rough idling
  • A reduction in engine performance
  • Poor air-fuel ratio
  • Poor fuel economy 
  • Engine stalls while idling
  • The smell of unburnt fuel
  • Failed emissions test
  • Engine knocking 

Can I drive with a bad EGR Valve?

Yes, even if the EGR valve fully fails, you can still drive your car. But your car will not run properly. You may observe some symptoms of bad EGR such as unstable idling, engine check light, unburned fuel smell from exhaust, poor performance of the engine, and emissions check failures.

Can EGR Valve be cleaned?

Yes, maximum problems of the EGR system may be resolved by carefully cleaning the valve with a throttle body cleaner. After proper cleaning, you won’t need to change your valve.   

What are the types of EGR Valves?

  1. Gasoline exhaust valve
  2. Diesel high-pressure EGR valve
  3. Vacuum-operated EGR valve
  4. Digital EGR valve 
  5. Diesel Low-pressure valve

How do I know my EGR Valve is bad?

As you observe the following signs, it means that you have a bad EGR valve and you need to replace it:

  1. A high reading of the engine warning light
  2. Failed emissions test
  3. Poor acceleration
  4. Engine overheating
  5. The smell of unburnt fuel
  6. A reduction in the engine performance
  7. Engine stalls while idling
  8. Unbalanced air-fuel ratio
  9. Poor fuel mileage

Does removing EGR increase power?

Yes, the removal of the EGR valve may result in a slight increase in power for some engines. When an EGR delete works properly, it increases the oxygen density in your engine. That means a boost in horsepower. 

What are the benefits of an EGR valve?

The EGR valve plays a vital role in recirculating the exhaust gases. There are many benefits of the recirculation of exhaust gases including the low emissions of the exhaust gases. This process also helps to improve the overall performance of the engine. These recirculated exhaust gases also assist in improving the air-fuel ratio without the need to draw in extra air from the intake manifold.

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