Most cars produced in recent years contain an exhaust gas recirculation system or EGR system for short. This system routes a portion of your exhaust gases back through the engine. Such recirculation eliminates many toxic exhaust substances and also provides vital cooling to your engine. Ultimately, EGR systems promote cleaner emissions and better fuel efficiency.
As time goes on, however, an EGR system may develop problems that hinder it from providing the correct results. In some cases, the system may allow an excessive amount of exhaust back into your engine. If you would like to learn more about what can cause this problem, keep reading. This article outlines three frequent causes of excess EGR system flow.
1. Valve Stuck in Open Position
In order to optimize performance, an EGR valve allows exhaust to enter your engine at some times while preventing it from doing so at other times. Your car uses information provided by its sophisticated sensor system to determine when – and for how long – to open the EGR valve. Yet if your EGR valve becomes stuck in an open position, it cannot prevent exhaust from entering the engine.
This issue almost always stems from the accumulation of problematic deposits on the valve body. Soot and other byproducts found in your exhaust can build up to such an extent that the valve cannot fully close. The excess flow of exhaust dilutes the amount of oxygen available in the air-fuel mixture, leading to rough idling, misfires, and even engine stalling.
To prevent build-up from affecting the performance of your EGR valve, most experts recommend having your EGR valve cleaned and inspected about once a year.
2. Dirty Air Filter
In a perfectly balanced engine, air and fuel would mix together in such precise proportions that every last bit of the fuel got burned up. Yet few engines can achieve this result in real life. Instead, some unburned fuel escapes from the engine along with the exhaust. Your EGR system promotes fuel efficiency by recirculating this fuel through your engine a second time.
Unfortunately, this function can end up leading to problems for engines whose air-fuel ratio gets too far from the ideal. Rich fuel conditions – in other words, too much gasoline relative to the amount of air – means that more fuel than usual will escape your engine unburned. As a result, the EGR valve will remain open even at times when it normally wouldn’t.
One of the most common culprits here has to do with your car’s air filter. An overly dirty filter restricts airflow into your engine, often leading to rich fuel conditions. By replacing your air filter, you should not only restore an ideal air-fuel ratio, but also the problems associated with excessive EGR system flow.
3. Bad Gasket
Another common cause of excessive EGR flow has to do with the gasket used to create an air-tight seal between the EGR valve and its mounting surface. Although EGR gaskets consist of heavy-duty and heat-resistant materials, they may develop cracks and other problems as time goes on.
A damaged EGR valve gasket potentially allows exhaust to leak into your engine, even when your EGR valve remains in a closed position. The only solution to this issue involves having a new gasket installed as soon as possible. EGR valve gaskets come in a variety of different materials, including paper and asbestos-containing copper, and steel gaskets.
Yet car owners can usually get the best results from a rubber gasket – one that contains both rubber and silicone. Such gaskets can withstand high temperatures while still retaining the flexibility needed to create a fully air-tight seal.
Your EGR system plays a vital role in the overall efficiency and performance of your car. For more information about how to prevent excess EGR valve flow, contact Columbus’ auto repair experts at White’s Automotive Center.
