The aesthetic of contemporary automobiles is the array of systems engineered to increase its performance and decrease its engine emissions. Among those systems is the Exhaust Gas Recirculation (EGR) System, designed to reroute exhaust gases to return to your car’s intake to assist in emission control.
The EGR valve is the primary element of your EGR system, which enables any of this. It’s as straightforward as its name says — a valve that automatically opens and shuts as required. What happens whenever your vehicle’s exhaust gas recirculation valve fails?
Typically, a faulty EGR valve would manifest a few symptoms that warn you of the problem, but how could you distinguish the symptoms of a faulty EGR valve from those of different engine troubles? In this article, we’ll be discussing the most typical signs of EGR valve failure.
But before we get into the symptoms, let’s take a quick look at what an EGR valve is, its function, and why it’s vital.
Bad EGR Valve Symptoms
- Poor Engine Performance
- Increased Fuel Consumption
- Rough Idle
- Fuel Odor
- Engine Knock
- Increased Exhaust Emissions
- Failed Emissions Test
- Surging or Stalling
- Check Engine Light
Table of Contents
What Is An EGR Valve?
Your vehicle’s EGR system minimizes the quantity of NOx emitted from the exhaust of your car. Recirculating used exhaust gases accomplish this to go back into your engine to cool its combustion chamber.
By substituting inert exhaust gas for a part of your engine’s typical air/fuel mixture, the heat of combustion decreases, therefore limiting NOx production. However, exhaust gases might be fed into your engine solely under specified circumstances.
If EGR operates at the incorrect moment, your car’s engine performance will decrease. As a result, its EGR system includes an EGR valve that controls the stream of exhaust gases. Your EGR valve is often located on your engine’s intake manifold.
This valve is connected to your exhaust manifold through the tubing. If the operations are proper, your EGR valve opens, enabling exhaust gases to reenter your engine and be consumed during regular combustion.
Several EGR system configurations are being used nowadays. The EGR valve is actuated immediately by the exhaust backpressure and engine vacuum in certain older automobiles. However, most current cars include one or multiple solenoids that are electronically operated.
These solenoids can manage the vacuum feed to your EGR valve or activate the valve directly. A computer, known as the PCM or powertrain control module, controls the solenoids in response to data from numerous sensors.
How Does EGR Valve Work?
To enable proper engine combustion, your automobile engine sucks air from the environment, air which is composed of around 1% argon, 20% oxygen, and 79% nitrogen, water vapor, and carbon dioxide. Whenever the air/fuel mixture is fired inside the combustion chamber, temps over 1360°C are produced.
Nitrogen oxide (NOx) is formed when inert Nitrogen gas combines with oxygen at such high temps. NOx is a significant pollutant generated by automobile engines and has been detrimental to our respiratory system and well-being.
To limit NOx emissions to the environment, exhaust flow is diverted into the combustion chamber, lowering the temperature and inhibiting the generation of NOx.
While your engine is started for the first time in a day or when it is only warm, your EGR valve remains closed, preventing exhaust gas from returning to your engine. This assists the engine is rapidly reaching its operational temperature.
While you accelerate and your engine temp increases, its EGR valve progressively opens to allow recirculation to your engine intake; but, if you brake or stop your car, the EGR valve returns to its initial closed state.
This occurs multiple times during your drive to guarantee that the vehicle’s fuel economy and pollution levels remain below acceptable limits.
Symptoms Of A Bad EGR Valve
EGR valve problems might create difficulties with your EGR system’s circulation and functioning, resulting in performance concerns such as low power, poor acceleration, and reduced fuel economy.
Additionally, it could result in an upsurge in car emissions. Owing to the development of soot particulates, carbon residues, and impurities from fuel, your EGR valves could get jammed closed or open.
Highway driving conditions are optimal for your EGR valve since longer and quicker travels enable your engine to reach temperatures sufficient to burn off carbon deposits. But urban traffic situations might promote the accumulation of such deposits.
While EGR valve symptoms vary, the following are the most frequent signs of a failing EGR valve:
Poor Engine Performance
Even though your EGR system is designed to cool the cylinders, you don’t wish your EGR valve to be open at all times. When the EGR valve is open at maximum rpm, your engine will have less combustible air where it’s most needed.
A faulty EGR valve will result in engine efficiency issues. Whenever you press on the accelerator pedal, you will almost certainly encounter acceleration issues and a loss of total power. This is because the air/fuel ratio is out of balance.
Consequently, your engine will need more significant fuel simply to generate some power. Then you’ll pay extra for fuel since you’ll have a poor fuel economy in addition to poor fuel efficiency.
Increased Fuel Consumption
A faulty EGR valve is most probable to occur in your car, consuming more fuel than usual. For example, your car typically gets 10 liters every 90 kilometers or 25 miles/gallon. If you suffer a defective EGR valve, your gallon/mile will rise, forcing you to spend extra dollars on fuel.
Additionally, your EGR valve is meant to assist in increasing your car’s fuel economy. As a result, if your EGR valve is compromised, that functionality is lost, forcing your car to raise your fuel consumption. Your EGR valve returns exhaust gas to your engine while maintaining a constant temp inside its combustion chamber.
As a result, if your EGR valve fails to operate correctly, the combustion chamber could reach an abnormally high temperature, resulting in the discharge of nitrogen gases into the environment.
If you have a stuck open EGR valve, you will experience a rough idle, even more so if your car has not even warmed up. This is due to the EGR valve often starting in its closed state. But, if your EGR valve is jammed closed, you might notice additional issues when your car is idling after its engine has fully warmed up.
That’s because your EGR valve is usually open during this period since it recirculates the exhaust to reduce the combustion chamber’s total temperature level.
Due to the increased fuel consumption, additional hydrocarbons will be discharged by your exhaust. This will amplify a fuel smell to the extent that car occupants will be able to smell it within the car’s cabin.
Clearly, you will not prefer to continue inhaling this since it’s unhealthy. As a result, this will serve as a motivator to solve your EGR valve issue immediately.
One of your EGR valve’s less common benefits is that it lessens engine knocking. Maintaining lower heat inside the combustion chamber keeps your fuel from burning prematurely. Although this isn’t always the case with a defective EGR valve, the odds significantly increase if your EGR valve is jammed closed.
Keep a sharp ear out for any banging if your check engine light is up due to a defective EGR valve. If possible, you should make fixes promptly to avoid additional engine harm.
Increased Exhaust Emissions
Since the primary objective of your EGR valve is to minimize emissions, you can anticipate that if it’s not functioning correctly, your emission levels will rise. Indeed, if your car has a malfunctioning EGR valve, it’ll almost certainly fail any emissions test.
If your vehicle’s EGR valve is faulty, you might notice a minor increase in smoke, although this is not generally frequent. Also, smoke coming from the EGR itself might be possible, caused by a leaking EGR valve gasket.
Engine Stalling or Surging
Whenever your ECU anticipates your EGR valve to go close, an EGR valve stuck open or blocked might toss off your engine’s air/fuel ratio. This might result in engine stalling or surging during acceleration. This could activate the fail-safe mode or limp mode on your car.
A faulty EGR valve might cause your car’s engine to overheat. Since a blocked EGR valve doesn’t prevent the emission of nitrogen oxides towards the environment, your engine’s temp could rise to unsafe levels.
Additionally, it’ll keep unburnt fuel within your exhaust, which can result in a strong fuel odor in your car and a decrease in its fuel efficiency. When the temperature reaches a dangerously high level, your engine could eventually knock.
Check Engine Light
Numerous sensors monitor your engine performance, emissions, and your EGR valve’s functioning. Whether your EGR valve is blocked, jammed open, or closed, your car’s check engine light will illuminate.
Although your check engine light would often point directly to your EGR valve, it’s conceivable for it to illuminate as a symptom rather than a cause. For example, you could have a check engine light indicating misfires or an excessive amount of exhaust chemicals, even if a faulty EGR valve causes the issue.
Types Of EGR Systems
There are multiple types of Exhaust Gas Recirculation Systems available for thousands of kinds of engines, yet their functions and aims are all the same. The following are the many EGR configurations utilized on diesel and gasoline engines.
Vacuum-Controlled EGR System
Typically present in earlier automobile designs, the Vacuum-controlled EGR System features a metallic, spherical, and wide valve. It’s often positioned outside your engine but nearer to its top and measures 3 inches in diameter. These older automobiles utilize a vacuum hose that regulates the position of the EGR valve.
A tubing links its carburetor’s intake output to the head of an EGR. Within the steel disc of the EGR valve are a spring, plunger, and vacuum diaphragm.
Electronic-Vacuum-Controlled EGR System
This type of EGR system emerged after the preceding one, which is why this sort of automobile is considered semi-modern. The Electronic-Vacuum-Controlled EGR System is essentially a cylinder or smaller block with a freely movable electronically controlled EGR valve.
The valve operates similarly to the earlier model, except for a position sensor that transmits position signals to the vehicle’s computer for quicker and more precise control.
Certain automobile manufacturers have replaced the EGR valves with EGR jets situated at the bottom of the engine’s intake manifold. However, specific high-performance engines, such as those equipped with Variable Valve Timing (VVT), could minimize NOx emissions even without the assistance of the EGR system.
Digital EGR System
This EGR System is found in the majority of current automobiles. This configuration functions in a different manner than a vacuum-controlled EGR. It makes use of an EGR valve that’s electronically regulated by the engine control module (ECM).
The ECM gathers data from various sensors across the car to calculate the optimal location of an EGR valve along your trip.
EGR Valve Stuck Closed vs. EGR Valve Stuck Open
There are two distinct types of bad EGR valves, each with its own set of symptoms. The EGR valve could malfunction in one of two instances: it can remain open permanently or closed constantly.
EGR Valve Stuck Closed
An EGR valve stuck closed can completely prevent exhaust gases from entering your intake manifold. You’ll discover several of the indications listed below:
- Tapping or Pinging Noise
During lower engine speeds, a tapping or pinging sound is produced by your engine. This noise is caused by your fuel igniting too early when it comes into contact with high temps.
- Loud Bursts
Audible bursts, a second ignition might occur after the standard ignition, and these two could merge to provide significant power to harm your engine.
- Increased Smoke Emissions and Failed Emission Tests
Your vehicle doesn’t pass the emission test. High temps inside your combustion chamber promote the creation of large amounts of nitrogen oxides that are then discharged via your exhaust.
- Check Engine Light
On the dash, your Check Engine will illuminate.
EGR Valve Stuck Open
As a result of an EGR valve stuck open, exhaust gases can run continuously through your intake manifold. You’ll discover one or several of the symptoms listed below:
- Rough Idle
A rough idle whenever your engine is first started (cold start) and occasionally at a stoplight or when seeking a parking space (low speeds in a fully warmed-up engine).
Engine stalling even while idling.
- Reduced Fuel Economy
You’ll notice a significant increase in fuel consumption.
- Fuel Odor
You can sense mild or strong fuel odor when running your vehicle due to the increased amount of hydrocarbons exiting the exhaust pipe.
- Increased Smoke Emissions and Failed Emission Tests
Your vehicle doesn’t pass an emissions test. Suppose your engine is operating at low RPM. In that case, the lower temps inside your combustion chambers restrict all the fuel from igniting fully, leading to a significant increase in the discharge of unburnt hydrocarbon gases exiting the exhaust pipe.
- Check Engine Light
On your dash, your Check Engine light activates.
- Poor Engine Performance
You get the sensation that your engine is underpowered, particularly at low speeds.
How To Test An EGR Valve?
Numerous other issues may simulate a bad EGR valve. To confirm that the EGR valve is the culprit, you’ll have to conduct a complete analysis of your car, which includes the following:
Inspect For Diagnostic Trouble Codes
The first step is to look for Diagnostic Trouble Codes or DTCs that might help you narrow down your diagnosis procedure.
Automobiles manufactured after 1996 featuring onboard diagnostics or OBD 2 and specific earlier models with OBD 1 could often generate a code if there’s a problem with your EGR system.
A scan device or code reader could check for diagnostics issue codes. You can also get an affordable OBD II code scanner for your smartphone nowadays.
It’s critical to note that DTCs don’t always indicate the specific nature of the vehicle’s issue. Codes are only a jumping-off point for more diagnostics.
Conduct a Visual Check
Following that, you’ll desire to do a visual assessment. Inspect your EGR valve’s control unit for concerns such as torn wires and faulty vacuum hoses.
Fix any errors discovered during your visual check, clear any DTCs, then repeat the visual examination to determine if the problem reappears.
Evaluate your EGR Valve
There’s no one-size-fits-all procedure for testing your EGR valve due to the various EGR system types being used nowadays. To thoroughly diagnose your car’s EGR system, you should study the relevant details in a repair database or repair manual.
EGR Valve Replacement Cost
The typical cost of replacing a bad EGR valve is around $225 to $800, based on the car and the service shop. Your EGR valve should cost between $150 up to $400, whereas labor should cost between $75 up to $400.
However, before immediately replacing your EGR valve, check to see whether it can be cleaned. Remove your EGR valve and clean it using a brush and a carb cleaner. If this method helps, you’ve already saved a couple of hundred dollars!
However, if the issue is narrowed down to your EGR valve or cleaning, this doesn’t solve the problem. There’s both good and bad news for you. The good news is that it’s simple to change with even a modest technological know-how-to. On the other hand, the bad news is that your EGR valve is somewhat more costly for such a tiny component.
Although an aftermarket valve for certain cars may be found for as low as $50, the typical cost is between $150 and $400. If you seek an OEM aftermarket component, you should budget around $250 to $600.
If you hire a technician to repair the component, labor expenses typically vary from $75 to $400. Thus, although DIY-ing might save you some money, you’ll still be responsible for the quantity of the expense.
Your EGR valve is a critical component of your car’s emissions system. It doesn’t only recirculate exhaust gases back into your engine via its intake manifold. Still, it also effectively helps maintain your combustion temperatures lower, therefore reducing some of the toxic nitrous oxides generated during combustion.
Whenever your EGR valve malfunctions, your car might idle irregularly, perform poorly, flunk any emission test, and your check engine light might illuminate. The best approach is to have it repaired immediately. If it’s beyond maintenance and fixing, your only option is to have it replaced right away.
If it has impacted more car components, your repair prices might increase exponentially. Keep in mind that operating a car with a bad EGR valve could be detrimental to both the car and the environment. Before replacing your car’s EGR system, confirm that the system has been correctly diagnosed.
What happens if the EGR valve is blocked?
Once your EGR system becomes blocked, or the valve becomes jammed closed your engine’s combustion temperature rises. This could result in pinging and surging during moderate acceleration. A bad EGR valve is among the reasons for black exhaust in a diesel-powered engine. In either situation, your Check Engine light can illuminate.
What causes an EGR valve to clog up?
Both are prone to jamming or improper fitting due to carbon, soot, and even oil accumulation surrounding the valve seat. Whenever carbon and soot layers accumulate around your EGR valve seat, your valve becomes incapable of closing completely.