EGR valve - how does the EGR solenoid valve work and what is it for? How to remove its malfunction?

Reducing emissions of harmful volatile substances from the combustion of fuel at some point became a key measure in the automotive industry. Many devices and systems are used for this, such as:

• HORN;
• catalyst;
• particulate filter;
• AdBlue.

Additional components in the engine and its accessories often affect its operation, and if they work properly, they are invisible. At the moment of malfunction, it becomes more difficult, which makes life difficult for many drivers. A damaged EGR valve causes symptoms similar to a failed turbocharger.. So, how to properly diagnose a problem in an engine with an EGR valve?

EGR valve in a car - what is it for and what is it really?

The EGR system is responsible for re-entering the exhaust gases resulting from the combustion of fuel into the cylinder. When asked why an EGR valve is needed, the simplest answer is that it is designed to reduce the amount of harmful nitrogen-toxic compounds (NOx). This is due to a decrease in temperature inside the combustion chamber. Directing the exhaust gases back to the engine and lowering the combustion temperature reduces the rate of the fuel oxidation process. The EGR system is designed to create more difficult conditions for the combination of oxygen with nitrogen, which in turn is to minimize the amount of harmful gases..

EGR operation in the engine

The EGR solenoid valve is not a separate device, but a system responsible for exhaust gas recirculation.. However, most often it is associated with the EGR valve, which causes a lot of problems. It is located between the intake and exhaust manifolds. Especially in larger petrol engines and vehicles with diesel units, it has additional cooling. This is necessary because of the extremely hot exhaust gases leaving the combustion chamber and the need to redirect a large amount of them back into it.

The operating range of the EGR system is narrow because the EGR valve itself is not constantly open. Under the influence of a signal received from the engine controller, the EGR opens, smoothly regulating the flow of exhaust gases. This process occurs only at an average engine load, because the injection of exhaust gases into the combustion chamber reduces the amount of oxygen, and therefore reduces the performance of the unit. EGR in the car does not work at idle, in a small rev range and at maximum load.

EGR valve - how to check if it works?

It is necessary to connect a diagnostic system to verify that the EGR valve is working.. If you do not have access to it, you can simply go to the nearest auto repair shop. Remember, however, that the cost of such diagnostics is at least several tens of zł, depending on the car model.

Symptoms of damaged EGR valve

The symptoms of a damaged EGR are very characteristic and noticeable. An EGR malfunction causes:

• an excess amount of black smoke than diesels;
• sudden or complete loss of power;
• car stalls at idle. 

In such situations, it is usually necessary to clean the EGR.. As a last resort, the EGR valve needs to be replaced.

How to clean the EGR valve?

You don't have to go to a mechanic to clean the EGR valve. If you have at least a little automotive knowledge and a few keys, you can successfully do it yourself. Adaptation is not required for pneumatically actuated versions, however, it may be required for more modern electronically controlled valves, precluding an effective self-repair.

What do you need to clean the EGR valve yourself? 

First of all, a cleaning agent (for example, extractive gasoline or nitro thinner), a brush, wrenches for unscrewing the valve (often hex) and gaskets. As we mentioned above, look for this device between the exhaust manifold and intake manifold. After unscrewing and removing it, it is very important to clean only the part responsible for moving the valve, and not the pneumatic elements and diaphragm. They are made of rubber and can be damaged by aggressive liquid.

Do not be surprised if after disassembly you see a lot of soot. A good solution is to prepare a not very wide, but deep container, into which the EGR valve is immersed and left for several hours or a day. This way the black goo will dissolve and you can clean all the nooks and crannies with the brush. After the job is done, be sure to give the EGR a good wipe before putting it in the car.. Be aware of new gaskets.

How to clean the EGR without disassembly?

Products available on the market allow the removal of carbon deposits and other contaminants without dismantling components. Of course, there will be a large number of supporters and opponents of such a decision, and each of them will be partially right. The preparation in the form of a spray is applied to the intake system in place, depending on the need to clean a particular part. Application is carried out on a running and warm engine according to the product manufacturer's instructions. Sometimes, instead of cleaning, it may occur to someone to muffle the EGR valve. What does it include?

Jamming EGR - side effects. When is a repair needed?

For some drivers, jamming the EGR has only a positive effect - less smoke, no problems with engine power fluctuations and elimination of jerks. However, it is not only about driving, because this system is related to the quality of exhaust gases. EGR reduces the emission of toxic substances, therefore it is necessary to comply with the regulations. In more modern cars, which, in addition to the valve itself, also have a position sensor and monitor the level of boost pressure, installing a plug in the valve will affect the operation of the assembly. In such cases, the process should be performed by an experienced mechanic familiar with electronics.

What are the consequences of blanking the EGR? Basically they concern technical inspection. If the diagnostician, when inspecting the car, detects violations related to the operation (more precisely, the lack of operation) of the exhaust gas recirculation valve, he will not raise the inspection. In addition, failure to comply with strict emission standards is also punished by the police. In cars built to fit, the owner can expect a fine of PLN 5.

EGR shutdown or EGR valve replacement?

If the vehicle is older and the vehicle does not have an EGR sensor, blanking off the EGR valve is simple. What's more, replacing the EGR valve can be very expensive. An EGR solenoid can be expensive, as is labor. Everything can be several hundred zlotys. Instead of paying to buy a new part and replace the EGR valve, some decide to putty it.

EGR solenoid valve plug on diesel and gasoline and consequences

High costs for replacing the EGR valve, the desire to avoid repeated straight up in the future - all this makes many drivers decide to go blind, i.e. disable EGR. Does it have any consequences? What happens when you turn off the EGR valve on a diesel or gasoline engine? Probably... nothing. A side effect of extinguishing the EGR solenoid valve may be the light check engine. In newer vehicles, the effect of disabling the EGR may be reduced performance gain in the midrange speed range.

If you want the EGR system, including the EGR valve and sensor, to function flawlessly for as long as possible, try to clean the EGR solenoid valve regularly.