Exhaust System auto parts: Valve egr exhaust control
Checking the exhaust gas recirculation system valve serviceability is too difficult: diagnostics of the exhaust system is not only time consuming, it also requires the use of professional equipment. Therefore, it is better to entrust the inspection to specialists at a service station.
In old cars, where no backpressure is created in the exhaust system, the inspection involves removing the valve. The vacuum of 250 mm Hg is applied with a vacuum pump connected to it. If the component is serviceable, its rod will be retracted opening the locking mechanism, and the vacuum will remain at the set level for not less than 30 seconds. Otherwise, the component is to be replaced.
In modern vehicles with backpressure in the catalyst, performing the diagnostics as described above is impractical. In such cases, during the check, follow the recommendations of the manufacturer of the vehicle.
You can notice that the EGR system valve needs diagnostics by the following symptoms:
The most common reason of EGR valve malfunction is the use of substandard fuel. The components contained in it enhance formation of soot deposits, which eventually results in jamming of the valve, and have a negative effect on metal components of the engine and related systems.
Fuel injectors fouling, deterioration of pump performance, and loss of tightness of the intake system impair the process of the air-fuel mixture preparation. Its leaning may result in an increased exhaust gas temperature, which leads to burning-out of the valve. This fault may also be caused by malfunctions of the ignition, timing or injection systems, when the fuel burns in the exhaust tract.
A common fault of the EGR valve is rupture of the membrane. It may occur due to accumulation of fouling on the surface of the diaphragm, poor quality of the component, or incorrect maintenance of the valve, such as using aggressive detergents for cleaning it.
Repairing of the component is limited to cleaning. To remove dirt and soot deposits, first tap the body of the valve with a soft faced hammer, then shake out or blow out the crumbled deposits from the inside. The outlet hole can be carefully cleaned with a small screwdriver. Remember to never flush the valve with solvents.
To replace a faulty valve, follow these steps: