What are the Sings of Bad EGR Valve?

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 EGR system. The exhaust gas recirculation (EGR) valve is a 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 working, causes and symptoms of a bad EGR valve.

What is an EGR Valve?

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

EGR Valve
Image Credit (Mechanicalboost.com)

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.

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.

Bad EGR Valve Symptoms

Following are the symptoms of a bad EGR valve:

  1. Check Engine Warning Light
  2. Poor Acceleration
  3. Engine Overheating
  4. Low Engine Performance
  5. Unbalanced Air-Fuel ratio
  6. Poor Fuel Mileage
  7. Engine stalls while idling
  8. Smell of Unburnt Fuel
  9. Failed Emissions Test

1) Check Engine Warning Light

The check engine light appears due to a faulty EGR valve. This light may also appear due to many other reasons. As the check engine light turns on, it shows that you most probably have a faulty EGR valve. The EGR valves take instruction by the engine control unit (ECU). The ECU also controls the check engine light illumination.

2) Poor Acceleration

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 due to that exhaust gases flow into the vehicle’s intake manifold before the engine needs them. This leads to poor acceleration of the vehicle. The excess of air creates a lean fuel-air mixture inside the combustor without the correct ratio of oxygen and air. This reduces the power in the combustion cycle.

3) Engine Overheating

A failed or damaged EGR valve may cause engine overheating. A bad exhaust valve cannot stop the discharge of the exhaust gases into the environment, which can increase the engine temperature up to a hazardous level.

In addition, a bad valve can’t properly burn the fuel, and the unburnt fuel remains in the exhaust system, which may produce an unpleasant smell of gasoline inside the car. This also reduces the efficiency of fuel. Eventually, if the temperature reaches up to a very high level, the engine may start idling.

4) Low Engine Performance

The reduction in the 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.

5) Unbalanced Air-Fuel ratio

The imbalance of the air/fuel ratio is another sign that leads to poor fuel efficiency. In such conditions, your engine consumes more fuel and forces you to buy lots of fuel or gasoline for your car.

6) Poor Fuel Mileage

The EGR valve is also designed to improve 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.

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 litres per 80km. If the car EGR valve fails, it increases gallons per mile and forces you to consume more money to fuel the vehicle.

7) Engine stalls while idling

If the EGR valve clogs 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 the new one.

8) Smell of Unburnt Fuel

Because the EGR valve is not working properly, the engine consumes more fuel than normal, causing more hydrocarbons to be emitted from the vehicle exhaust valve. This increases the smell of fuel, and if your air conditioning is not in recirculation mode, you can smell it in the vehicle.

This smell is very hazardous for your health. This is a clear symptom that there is a problem with the engine.

9) Failed Emissions Test

The emission test is performed to check the engine exhaust gases 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.

Causes of EGR Valve to go bad

The following reasons cause the EGR valve to go bad:

  • Clogged EGR passages or carbon buildup inside the passages
  • Defective EGR Vacuum Solenoid
  • Faulty EGR switching valve
  • Clogging of the EGR valve
  • Clogged Catalytic Converter
  • There may be issues with the EGR vacuum control
  • Dirty or clogged air filters
  • Blown or leaked EGR valve gasket
  • Leakage in the intake manifold
  • Faulty EGR temperature sensor
  • A faulty or damaged turbocharger
  • Faulty DPEE sensor which is used for Mazda or Ford vehicles
  • Incorrect connection of the vacuum hoses

FAQ Section

How do you know if you need a new EGR Valve?

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

  1. High reading of the engine warning light
  2. Failed emissions test
  3. Poor acceleration
  4. Engine overheating
  5. 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

What is the replacement cost of EGR Valve?

The replacement cost of an EGR valve varies according to the model of the vehicle, type of brand, and the area where you. The average replacement cost of an EGR valve is from $240 to $360. The cost of the labour is between $70 to $85, and the cost of the parts is in between $160 to $275.  

How to tell If an EGR Valve Is Bad?

A bad EGR valve generates the following signs:

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

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