Increased fuel consumption is caused when the valve is constantly open. The incorrect function of the EGR valve can cause the erratic performance of your vehicle. Poor performance can be caused when the valve is open or closed. low engine speeds with a warmed-up engine) can be caused when the EGR is constantly open and a continuous flow of exhaust gases goes into the intake manifold. Whereas urban driving conditions can allow these deposits to build up.ĮGR valve symptoms can vary, however, the most common symptoms of a faulty EGR valve are explored below: Your engine has a rough idleĪ rough idle when starting your vehicle or during brief stops (i.e. Motorway driving conditions are the most favourable to your EGR valve as longer, faster journeys allow the engine to get hot enough to get rid of carbon deposits. It can also cause vehicle emissions to increase.ĮGR valves can become stuck ‘open’ or ‘closed’ due to a build-up of soot particles, carbon deposits and dirt from fuel. What are the symptoms of a failing EGR valve?Ī faulty EGR valve can cause problems with the flow and operation of the EGR system leading to performance issues including a reduction in power, reduced acceleration and decreased fuel efficiency. The ECM receives inputs from various sensors throughout the vehicle to determine the prime position of the EGR valve throughout your journey. Most modern cars utilise an electronically controlled EGR which is controlled by the vehicle’s engine control module (ECM). The vacuum is often regulated by a computer-controlled solenoid. It is a straightforward system which utilises a vacuum to switch the EGR valve from closed to open. A vacuum-operated EGR valve is usually only found in older vehicles. There are two types of EGR valves a vacuum-operated and an electronically controlled EGR valve. This helps to ensure the car maintains fuel efficiency and emits fewer emissions. This happens continually throughout your journey to ensure recirculation only occurs when the car is at a working temperature. As you speed up and the engine reaches its operating temperature the valve gradually opens, however, should you slow down or stop the valve will gradually close. Operationally this means that when the engine is first started the valve stays in a closed position. The EGR valve is fairly simple when it is open exhaust gases are allowed through the EGR system to help control vehicle emissions, whereas when the valve is closed exhaust gases can’t pass through the EGR system. In order to achieve this, they are introduced back into the combustion chamber via the exhaust gas recirculation (EGR) valve this reduces the temperature and thereby inhibits the production of NOx emissions. To reduce the amount of NOx pollutant emitted from your vehicle, exhaust gases need to be cooled before being emitted from your vehicle.
NOx is one of the main pollutants from cars and is known to cause human health problems such as respiratory issues. The air combines with fuel and ignites in the combustion chamber where temperatures reach over 1370☌.Īt this high-temperature, inert nitrogen naturally present in air burns creating oxides of nitrogen (NOx). The EGR Valveįor combustion to occur in your car, it is necessary to draw in air (which is approximately 80% nitrogen and 20% oxygen) from outside of the vehicle. But what is it and what happens when it isn’t working properly? Our latest post gets to grips with why the EGR valve is so important as well as covering the most common symptoms of a faulty EGR valve. The EGR valve plays a vital role in regulating exhaust emissions and is a necessary component in countries and cities with strict emissions regulations in place.