An Overview of an EGR Valve and the Top Signs of Malfunction

Diesel and petrol automobiles have a device known as an Exhaust Gas Recirculation (EGR) valve. The purpose of the EGR valve is to prevent too many harmful emissions from being released into the environment. Many modern vehicles are built with EGR valves because of the legal requirements for car manufacturers to build vehicles that meet specific emission standards.

If you ever drive your vehicle and see black smoke or fumes coming out of your vehicle’s exhaust pipe, it probably means you have a bad EGR valve. In this case, you should take your vehicle to the nearest auto mechanic to have the EGR valve replaced.

How Does the EGR Valve Function?

An internal combustion engine generates nitrogen oxide during the combustion process. Nitrogen oxide is the smog you may see emitting from your vehicle’s exhaust pipe. A functional EGR valve reduces the level of nitrogen oxide by recirculating the exhaust gas back into the engine’s combustion chamber for reuse.

Exhaust gas recirculation reduces the engine’s combustion temperature to stop nitrogen oxide from forming. In addition, the exhaust system stays cleaner during this process and increases the vitality of the engine.

The EGR valve doesn’t operate if you fully accelerate or leave the engine idle because it would impact the engine’s performance and increase the likelihood of stalling or loss of power. But the EGR valve does operate as you accelerate your vehicle moderately.

How Do I Find the EGR Valve?

Motorists must maintain a functional EGR valve and replace it if it stops being functional. If your vehicle’s EGR valve stops working, it will diminish the engine performance and increase emissions. Neither of these things is good.

If you want to check out your EGR valve, you can usually find it near the upper portion of the engine cylinders. The intake manifold should be connected to the EGR valve because that is the component that helps it recirculate the exhaust fumes.

Of course, the location depends on the make and model of your vehicle because some car models have the EGR valve installed in a different location. For instance, you may find the EGR valve on the engine assembly’s exhaust side, using plumbing to connect to the intake manifold.

If you still have trouble finding the EGR valve, look in the owner’s manual of your vehicle for assistance.

The Top 7 Signs of a Bad EGR Valve

Carbon deposits accumulate in the EGR valve over time because of the mixture of oil and exhaust fumes. These carbon deposits resemble a tar-like substance and can block the EGR valve’s ability to open and close if too many deposits accumulate. So if the EGR valve cannot open or close appropriately, then too much or too little exhaust fumes will enter the engine cylinders.

Here are the top seven noticeable signs of a blocked or faulty EGR valve:

1) Check Engine Warning Light

The Check Engine warning light on the dashboard can come on for many issues related to your engine. Modern cars have engine control units, which are central computers that manage most of the systems and components in the vehicles. If the computer detects any functional abnormality with a part supporting your engine, such as an EGR valve, then it will activate the Check Engine light on the dashboard.

2) Engine Stalling / Reduced Power

Your engine may stall if too many exhaust fumes enter the cylinders at inappropriate times. Then your engine won’t be able to generate an adequate amount of power to keep your vehicle operating safely.

3) Black Exhaust Smoke

Perhaps one of the most noticeable signs of a bad EGR valve is when you see black exhaust smoke coming out of the exhaust pipe. This black smoke is the result of unburnt fuel trying to leave your exhaust system. As this happens, you will probably smell a fuel odour inside and outside your vehicle too.

4) Knocking Sounds from the Engine

A faulty EGR valve may result in knocking sounds from your engine because of the higher temperatures in the engine cylinders. The sounds generate when fuel in the cylinders is igniting at the wrong times. Your engine control unit should detect this problem early and illuminate your Check Engine warning light before the knocking gets too severe.

5) Rough Idling Engine

When an EGR valve cannot close due to being stuck open, it will cause the engine and cylinders to get colder. The result of which will be a rough idling engine. On the other hand, you could also experience a rough idling engine if the EGR valve is stuck closed rather than open.

6) Failing an Authorised Emissions Test

One way to know you have a bad EGR valve is if your vehicle fails its emissions test. After all, the EGR valve is supposed to reduce emissions from your car, so a bad EGR valve won’t be able to do its job correctly. Then your vehicle will produce too many exhaust fumes, preventing you from passing the emissions test.

7) Bad Fuel Economy

Poor gas mileage and a bad fuel economy are the expected results of a faulty EGR valve. For instance, if the engine gets too cold from the EGR valve getting stuck open, it will be more difficult for the fuel to ignite in the cylinders. Then you’ll have insufficient fuel and air combustion, which means your engine will consume more fuel to maintain the power demands you put on it. As a result, you’ll have to stop at a gas station to refill your fuel tank more frequently.

EGR Systems

Older vehicles were built with pneumatic vacuum-regulated EGR valves that required a vacuum to manage when the EGR valves opened and closed. As for modern vehicles, the engine control unit operates the EGR valves electronically. The electronic control unit transmits information to the EGR valve to know when to open and close. It is a much more reliable and accurate way to control the EGR valves than the old-fashioned method.

How to Respond to a Bad EGR Valve

When you notice the symptoms of a bad EGR valve, the best thing to do is stop and contact a tow truck company like Executive Towing Services to request a tow and have your vehicle taken to the nearest auto shop or mechanic for an inspection and a possible EGR valve replacement.