6 Signs Your Vehicle's EGR Valve Is Failing
Vehicle exhaust gases are a significant source of greenhouse gas emissions. Auto manufacturers use Exhaust Gas Recirculation systems, or EGR systems, to control the exhaust gases released into the atmosphere and to meet regulations.
The result is reduced fuel consumption, increased efficiency, and reduced emissions. How does the EGR valve work and what signs indicate a faulty EGR valve?
What Is An EGR Valve?
The combustion process of internal combustion engine cars creates nitrogen oxide (NOx) emissions as a byproduct, a pollution source. The EGR system regulates these emissions by returning some exhaust gas through the intake manifold into the combustion chamber. This process lowers the combustion chamber's temperature, reducing the amount of NOx produced.
The EGR valve is an essential component of the EGR system. It connects the exhaust to the intake manifold and regulates the amount of recirculated exhaust gas depending on the engine's requirements.
How The EGR Valve Works
The EGR valve has two main settings. Depending on the vehicle's condition, it is either in an open or closed position. Before a vehicle starts, the valve is usually in the closed position. Only a tiny amount of oxygen is required as the vehicle idles or moves at a lower speed, hence the EGR valve gradually opens to let more gas into the combustion chamber.
Exhaust gases reduce the amount of oxygen and increase the amount of water vapor, which helps maintain a lower combustion temperature and keep NOx emissions at a minimum.
On the other hand, the vehicle requires more torque as it accelerates, which calls for more fresh air. The valve, therefore, closes to prevent the exhaust gases from re-entering the combustion chamber and ensures that an optimal amount of oxygen is maintained.
EGR Valve Problems
A common problem with EGR valves is clogging or being stuck open or closed due to a buildup of carbon deposits. In extreme cases, the valve can be completely choked, preventing the recirculation of the exhaust gases. Many signs indicate a bad or failing EGR valve, most of which are engine-related problems. Following are the common signs that show your EGR valve is failing.
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Signs Of A Bad EGR Valve
1. Reduced Engine Performance
A faulty EGR valve affects engine performance by creating rough and jerky accelerations. It also reduces engine power, which is noticeable during low and high speeds. The problem is more noticeable at low speeds when the valve is stuck open and more apparent at high speeds when the valve is stuck closed. In worse cases, it can cause the engine to shut off while driving.
2. Rough Idling
A bad EGR valve, when stacked open, causes rough idling when you start the vehicle, and the engine is yet to warm up. That's because the valve is supposed to be at the closed position during startup. When it's stuck closed, you will notice the problem after the engine warms up because the valve usually opens up at this stage to recirculate the exhaust gases to lower the temperature of the combustion chamber.
3. Engine Knocking
The recirculation of the exhaust gas keeps the combustion chamber at a lower temperature and prevents premature ignition of the fuel. A bad EGR valve leads to reduced circulation. Hence the engine overheats and produces a knocking sound.
4. Smells Of Fuel Inside The Vehicle
A faulty EGR valve causes higher fuel consumption because the engine works harder than usual to propel the vehicle. The extra engine load creates a higher temperature and emits more NOx. The result is a constant smell of unburnt fuel inside the vehicle, which is detrimental to your health.