An EGR valve controls the level of exhaust gas that enters enter the intake manifold. The EGR stands for Exhaust Gas Recirculation.
This lowers combustion temperatures and reduces nitrogen oxide emissions, which contribute to smog. Although modern cars are equipped with EGR valves, they were not present on all vehicles until around 1990. If an EGR valve is not working, your car will have higher NOx emissions and may not pass a smog test. EGR valves can become clogged over time with carbon deposits. This can cause the valve to stick open or closed. If your EGR valve remains open, it will flood exhaust gas into the engine, which can reduce performance and increase emissions. If it's stuck closed, the engine won't get the benefits of recirculated exhaust gas, and emissions will be higher. If your electronically controlled EGR valve is not working properly, you should have it fixed as soon as possible. Not only will this improve your car's performance and reduce emissions, but it will also help keep your car running smoothly.
An EGR valve is responsible for recirculating exhaust gas back into the engine's combustion chamber. By recycling exhaust gases back into the combustion chamber, oxygen intake is reduced, which in return lowers the engine's high temperature. If the running temperature is high, it can enable Nitrogen gas to become active. Nitrogen and carbon dioxide are considered harmful emissions. When this valve goes bad, it can cause a number of EGR-related problems such as decreased performance, increased emissions, rough idling and even engine damage. If you are experiencing any of these issues, it's important to get the EGR valve fixed as soon as possible.
EGR valves come in a number of types. Typically, the vacuum operated valve is the most common among older versions. Most modern cars have electronically controlled EGR valves. Below is a list of EGR systems.
Vacuum operated EGR valves. These types have a vacuum solenoid that manipulates a diaphragm that opens and closes the EGR, which controls the exhaust gases entering the engine.
Digital EGR valves.
Gasoline EGR valves.
Diesel Low-pressure EGR valves are fitted in vehicles with diesel engines. They return high soot exhaust gases to the manifold through an inlet in the cylinder head. EGR valves are typically just before the diesel particulate filter (DPF) in the exhaust system.
There are a number of different ways your mechanic can test your car's EGR valve to see if it is working properly. If you bring in your car for repairs and the check engine light turns on, this is usually the first indication of EGR valve failure and that it needs to be repaired. Other than the check engine light, the other common way a mechanic will troubleshoot a failing EGR valve is by using a scan tool. This device hooks up to your vehicle's computer and reads information from all of its systems, including emissions data. After hooking up the scan tool, your mechanic will start the vehicle and then clear codes related to the EGR system. He or she may have you drive around for a few minutes before shutting off the engine so they can get more accurate readings from all of the car's sensors. Often, a failing EGR valve is stuck in the open or closed position. The mechanic will also check if all electrical connections relating to the exhaust gas recirculation EGR valve are properly fixed and working.
It isn't a good idea to drive with a bad EGR valve. A faulty EGR valve will cause decreased performance and increased emissions and lead to engine damage. An EGR valve stuck in the open or closed positions disrupts the optimal air-fuel ratio. This suboptimal air-fuel mixture affects the engine's fuel consumption. Increased fuel consumption lowers the overall fuel economy of the car.
EGR faults in a diesel engine also cause engine knock and rough idle problems, similar to an issue with the diesel particulate filter. Over and above the fuel efficiency losses, an EGR system emitting NOx emissions and carbon particles above the allowable limits will fail the exhaust emissions test.If your car's EGR valve is not working properly, have it fixed as soon as possible.
There are a number of ways your mechanic can repair an EGR valve. If the EGR valve is clogged, it may be possible to clean it out. This process involves cleaning carbon buildup caused by exhaust gases. The mechanic may also replace some gaskets and O rings which may have been damaged. Other times, however, especially if there is damage to the control system of the engine, new parts will need to be installed for the car's emissions and performance to return to normal.
The cost to replace an EGR valve will vary depending on the type of your car. It may be anywhere from $200 to $400. However, this is a relatively inexpensive repair in comparison to some of the other problems that can occur with a car's emissions system.
You can drive without the EGR valve but it's not ideal. However, this will likely result in reduced pick performance, increased fuel consumption and increased NOx gases emissions. If you are having engine trouble with your car but the EGR valve seems to be working fine, have it checked by a mechanic before you take any other steps. It may be something else causing the issue, such as a faulty oxygen sensor, a failing mass airflow sensor or even a crack in the exhaust manifold.
The EGR valve is located in the intake manifold of your car, usually on the backside of the engine. The position will depend on the make and model of your car. A mechanic at a repair shop should be able to guide you if you are unsure of where it is located in your vehicle.
When the engine starts or during normal operating temperatures, the exhaust gas recirculation EGR valve remains at the closed position. It does not let the exhaust emissions back into the combustion chamber. The exhaust gas recirculation valve gradually opens as the engine speeds increase and engine temperatures rise.
An EGR valve works together with other components in your car, such as the inlet manifold and oxygen sensor(s), the exhaust manifold and catalytic converter.
The ECU controls the electronics behind your car's emissions system. The EGR valve only works in concert with this computer and others to control engine performance and emissions. Since a faulty EGR valve can affect a number of other systems, it is important to have it repaired as soon as possible if it is not working properly.