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Common Symptoms Of A Bad EGR Valve You Might Not Know

The function of the exhaust gas recirculation (EGR) valve is to recirculate the engine’s emissions. It helps those gases to return to the combustion chamber instead of directing them to the exhaust emission system. The EGR system is crucial for reducing carbon emissions. As a concerned driver, you must be aware of the symptoms of a bad EGR valve to avoid contributing to polluting the environment.

What Are The Functions Of The EGR System?

Found in most gas and diesel engines, the EGR system keeps the emission of automobile’s exhaust gases in check. Including it in the vehicle’s framework is a standard government regulation that manufacturers must meet.

The EGR system reduces the combustion temperatures in the cylinder, which results in lower emissions and discharging fewer oxides of nitrogen (a pollutant). The working mechanism involves creating a diluted air-fuel mixture by allowing a metered amount of exhaust gas into the engine. Such a mixture lowers the combustion temperature by up to 300°F by burning more slowly.

The EGR valve is the main component of the EGR system. It regulates the amount of exhaust gas passing into the engine intake manifold. Be aware of the EGR valve symptoms because it indicates that your car is emitting more pollutants that the approved limit.

Symptoms Of A Bad EGR Valve

What problems does a bad EGR valve cause? The recirculation is designed to take place when the engine is at the optimum temperature to work properly. The engine underperforms or shows problems when the EGR occurs at the wrong time or does not happen at all.

egr valve symptoms
The engine will perform poorly.

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What are the symptoms of a faulty EGR valve? Well, EGR problems depend on whether the valve is stuck closed or stuck open. These are the symptoms of a bad EGR valve that you should be aware of.

Subpar Engine Performance

As the EGR valve monitors the volume of exhaust gases entering the engine, it is obvious that any issue with it will affect the engine performance.

You may feel reduced engine power when pressing down the gas pedal or experience acceleration difficulties. The long-term effects of these issues are bad fuel economy and the vehicle guzzling more fuel than necessary.

It happens due to the incorrect air to fuel ratio. As a result, the engine requires more fuel to yield any power.

The Engine Warning Light Comes On

Seems so obvious! The light flashes if there is a problem with the engine so it will come on when the EGR valve fails.

The engine control unit (ECU) monitors the activities of all engine components. It activates the light upon sensing that the valve fails to do its normal function.

The Engine Does Rough Idling

A malfunctioning EGR valve fails to control the volume of exhaust gases entering the chamber. As it remains in a closed or open position, the exhaust gas in the chamber is either too less or too much – leading to the idling of the engine.

Smell Of Fuel

Fuel odor inside the car’s cabin is one of the most obvious bad EGR valve symptoms. The smell is so strong that can be harmful to your health. The gasoline stink is the result of engine gobbling up more oil than necessary causing the tailpipe to discharge more hydrocarbons.

Failed Emission Test

A functioning EGR valve reduces the emission of a vehicle. When it’s failing, the exhaust pipe will discharge more pollutants than the approved level. Most countries require a vehicle’s emission test every six months. Check the EGR system if your car fails the test.

Warning Signs According To The EGR Valve’s Position

You already know that all problems occur due to two reasons – the EGR valve stuck open or it stuck closed. So, it’s possible to divide the symptoms of a bad EGR valve into two categories:

EGR Valve Stuck Open

An open EGR valve allows exhaust gases getting into the engine but at the wrong time. Common warning signs to look for are:

  • Rough idling
  • The engine does not kick off
  • Stalling and hesitation of the engine
  • The check engine light coming on
bad egr valve symptoms
Increased emission is a warning sign.

EGR Valve Stuck Closed

A closed valve does not let exhaust gases entering the engine at all. As a result, the temperature in the combustion chamber goes up and creates various problems. Common symptoms are:

  • Exhaust emission going up
  • Surging at Cruise speeds
  • Spark knock
  • A lighted check engine light

How To Troubleshoot The EGR Valve Problems

Even if your car showing symptoms of a bad EGR valve, it does not mean that you have to replace it. You should test it before throwing into the junkyard.

You can examine a vacuum-operated EGR valve with a handheld vacuum pump while a diagnostic scan tool is required for testing an electronic EGR valve. It is better to take the car to a servicing shop when the symptoms occur.

2 Comments
  1. Suresh Samikannu says

    For my Ford Fiesta Classic , my Mechanic Engineer told that the EGR valve is damaged and has to be replaced. I am observing, my car performance is very very worst and white smoke is coming. Also he inspected by scanning with the software in idle running engine condition, Software is telling that all are OK. Please confirm if i change the EGR valve, will the white smoke will stopped and the performance will be good.

    Thanks in advance

    1. chris says

      That sounds like the symptoms described here and I imagine that if an ME you hired told you it’s the EGR valve then it is the EGR valve.
      I don’t think that anyone without access to your car can tell you definitively whether or not one action will solve the entire problem.
      Best

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