The EGR or Exhaust Gas Recirculation system your Audi is equipped with has a very specific function- which is to minimize NOx formation by the engine. To make it happen, an array of different parts are employed- the most prominent being the EGR valve. Today’s blog post discusses everything there is to know about the EGR valve like- what is it and how does it help the exhaust gas recirculation system in putting a limit on NOx formation by the engine.

It also goes over some of the key indicators of EGR valve failure in Audi cars and things that can be done to get the most out of it.

EGR Valve: How Does It Limit NOx Emission?

The short answer is… by lowering the temperature inside the combustion chamber.

Our atmosphere is made of 80% nitrogen. Although nitrogen is pretty much safe to inhale, its oxides are not. Air enters the engine’s intake system contains an abundant amount of nitrogen. Even though this gas is inherently inert, it becomes highly reactive as it gets exposed to extreme temperatures inside the cylinder. Highly reactive N atoms can start forming bonds with the O atoms to generate oxides of nitrogen (NOx).

The EGR valve, in essence, prohibits the temperature inside the combustion chamber to go beyond a certain range; thereby preventing the formation of NOx inside chamber. It does that by routing a specific amount of exhaust gas into the engine’s air intake system via a cooler. If for some reason the EGR valve gives up, NOx emission by your Audi will skyrocket.

Signs Your Audi’s EGR Valve Is In Need Of Repair

Clue #1- Car idle rough

A steady supply of air-fuel mixture is necessary for a car engine to idle smooth. If your Audi’s EGR valve stays stuck open because of a mechanical deformity, an excess amount of exhaust gas may enter the cylinder; significantly destabilizing the air-to-fuel proportion inside the combustion chamber as a result. This is something that may contribute to a rough engine idle.

Clue #2- Reduced engine power

In addition to rough engine idle, you will notice a significant drop in your Audi’s torque output if its EGR valve is acting up. Wondering how a glitch in the EGR valve can contribute to reduced engine power in a vehicle? Well, as we’ve discussed above, a defective EGR valve can destabilize air-to-fuel proportion inside the combustion chamber; thereby contributing to an array of performance-related issues including reduced torque generation.

Clue #3- Engine warning light on

Isn’t it obvious??? Since a flaw in the EGR valve can result in an array of different performance-related issues; if it gives up, the on-board diagnostic system will left with no choice but to activate the check engine light. It is important to note that there are all sorts of different other reasons why a vehicle’s check engine light may get triggered and only a technician with the help of right equipment will be able to tell the exact reason that prompted the light to start flashing.

Clue #4- Odd knocking sound

Another recognizable sign of EGR valve failure in a vehicle is the appearance of a strange knocking noise from the engine compartment. If the EGR valve stays in closed position for too long, temperature inside the combustion chamber will skyrocket. This is something that can cause early ignition of fuel- giving off a strange knocking sound as a result.

Tips To Prevent EGR Valve Failure In Audi Cars

#1- Regular maintenance

The EGR valve, at the end of the day, is a simple mechanical device. As with any other mechanical parts of a vehicle, it is destined to all sorts of wear and tear. If you want to get the most out of your Audi’s EGR valve, you must ensure its upkeep. Additionally other components of the exhaust gas recirculation system like the EGR cooler should also be taken care of.

#2- Careful installation

Incorrect installation can result in premature EGR valve failure in a vehicle. Therefore, you should only choose a trustworthy service center to have your Audi’s defective EGR valve replaced.

European Motor Cars: Your Trusted Audi Service Center

When it comes to replacing a defective EGR valve Audi EGR Valve Replacement in your Audi, you should only choose a reputed auto service center in your locality. At European Motor Cars, we are extremely good at fixing complicated issues in Audi cars. We have been serving Audi owners of Summerlin, Spring Valley, and Las Vegas, NV, for over 30 years. Give us a call and book your next appointment today!

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