Symptoms of a Bad Egr Valve – Reasons and Solutions

Symptoms of a bad EGR valve call for quick diagnostic and repair steps. You can suspect a stuck or clogged valve if you witness engine idle, bad fuel economy, engine warning lights, or other symptoms.

However, these symptoms may also appear if you have a lousy temperature sensor or electrical faults in the EGR system. This blog post explains the common symptoms, causes, and repair methods to help you resolve the valve problem.

Why Does the Egr Valve Cease?

The EGR valve ceases because it gets stuck or jammed in an open or closed position due to the corrosive exhaust gases. Carbon and sulfur compounds, oil, or sludge may clog the valves and prevent them from moving. Moreover, you can suspect problems with a temperature sensor or EGR solenoid.

• A Jammed Exhaust Recirculation Valve

The most common reason behind an EGR valve failure is that it is stuck in a position. It can be stuck in an open or closed position and show different symptoms. The valve’s primary function is to open and close to recirculate the harmful gasses in the exhaust. If it gets stuck at one point, the gas will not move from the engine to the exhaust or exhaust to the engine. An EGR valve gets jammed if it wears out over time. Like other components, the valve has a specific life span, after which it deteriorates.

The valve works under high temperatures, which weakens it over time. Moreover, it handles the flow of some corrosive gasses that are damaging in case of continuous exposure. These factors affect the internal components like the diaphragm and pintle and jam the valve.
You need to consider two possibilities if you have a jammed valve. The first one is a valve fixed in an open position. It allows excessive waste gasses inside the engine, which dilutes the air-fuel mixture.

Here are some EGR valve stuck open symptoms:

• An open valve makes it difficult to start the engine resulting in a longer cranking period. The combustion chamber is unable to ignite a rich air-fuel mixture.
• An open valve produces a strong smell due to unburned fuel in the exhaust. It happens due to incomplete burning of the excessive recirculated gas.
• An open valve causes rough or uneven idle because a large air volume enters the engine and modifies the fuel-air ratio.
• An open valve causes the engine to stall and shakes the car. You might also feel vibrations in the cabin.
• An open valve causes the engine misfires and loss of performance.

The combustion chamber overheats when the EGR valve gets jammed in a shut position. It results in premature ignition of the fuel and air mixture.

Here is what happens when EGR valve stuck closed:

• A stuck valve overheats the engine because the gasses from the exhaust do not circulate back to the combustion chamber.
• A stuck valve produces a prominent smell due to the emission of toxic nitrogen oxides.
• A stuck valve causes a knocking sound as it disturbs the engine timing.
• A stuck valve causes rough idle because of pre-ignition.
• A stuck valve displays reduced fuel efficiency.
• The check engine light glows.

 

• Clogged Valve or Exhaust Pipe

The valve may not work if it gets clogged. If that is the problem with your car, you are in luck. Cleaning a clogged EGR valve solves the problem and retains its function. In this case, the valve will not channel the waste gasses into the engine.

A blocked valve requires quick action because, if ignored, it can cause severe damage to the engine. You will know of the blockage when you hear a knocking bad EGR valve sound.

There are multiple reasons behind the blockage:

• Carbon buildup due to combustion byproduct deposits blocks the valve. The carbon or soot particles are released when the engine displays incomplete combustion.
• When the valve recycles the exhaust gas, those particles accumulate and block it.
• Vaporized oil and sludge in the exhaust gas settle on the EGR valve and form a sticky compound. The sticky substance solidifies over time and blocks the valve.
• Sulfur compounds or other contaminants from the recirculated gas can clog the valve.
  Low-quality fuel and fuel additives leave deposits of various compounds on the valve.

 

• An Unreliable Engine Temperature Sensor

The EGR valve works with the help of various sensors, most notably the temperature and position sensors. So having a bad sensor is a common reason for a bad valve. The valve wears off because of the heat when the temperature sensor fails to detect high engine temperatures.

The EGR valve receives signals from the ECU to operate. The ECU determines its operation based on the temperature reading from the sensor. When the sensor provides the wrong details about the temperature of exhaust gasses, the ECU distorts the valve functions.
Sometimes the valve works at inaccurate timing.

The incorrect readings from the sensor cause the ECU to open or close the valve at the wrong time or for an indefinite duration. These problems lead to increased emissions and poor engine performance. The control unit presents diagnostic trouble codes indicating issues with the sensor. Try to troubleshoot these codes as soon as possible otherwise; the ECU will deactivate the EGR system.

• An Inoperative Egr Solenoid

The exhaust gas moves into the intake manifold when the solenoid in the EGR valve opens. The solenoid receives direct signals from the ECU to conduct the EGR function, but it prevents the valve from working when damaged.

The solenoid creates a vacuum flow that directs the gasses to move in the intake manifold for recirculation. When it stops working, the valve does not open or close. The ECU controls the solenoid depending on your speed, engine load, and other aspects.

The following factors can be the reason behind an inoperative EGR solenoid:

• Normal wear of the solenoid is inevitable after a certain period. It weakens due to constant cycling and exposure to varying temperatures. The internal parts lose their function over time and become less responsive.
• When you drive, the solenoid is continuously exposed to heat from the exhaust manifold. Excessive heat damages the internal parts of the solenoid, such as the coil.
• Leakage near the solenoid can lead to corrosion and failure of the solenoid. It can be an oil or fluid leakage in the vicinity.
• Disconnection of electrical power fails the solenoid. It may happen due to a short circuit or damage to the wires.
• The solenoid obstructs due to debris or other contaminants and fails to open or close.

 

• Electrical or Mechanical Egr Problems

The EGR valve may damage due to electrical or mechanical problems. It has electrical connections that may rust over time. The electrical contacts or wires get damaged due to moisture, electric overload, and other reasons. These problems cut the electric flow, and the valve gets stuck in an open or closed position. The EGR valve is also a mechanical component, so any damage to the moving parts damages the valve. The valve moves with the help of bearings, springs, and pintles that may get damaged over time.

Since both electrical and mechanical failures lead to a stuck valve, the engine can misfire. It answers, “Can a bad EGR valve cause a misfire?” The stuck valve affects the air-fuel mixture and causes misfires. Although not very common, the air-fuel mixture ratio alters due to blocked fuel filters. Thus, consider the engine filters if you cannot detect any other cause for bad EGR valves.

How To Fix a Failing Exhaust Gas Recirculation Valve?

To fix a failing exhaust gas recirculation valve, start by cleaning it with a carburetor or valve-cleaning agent. If cleaning does not restore the valve’s function, you should replace it to prevent severe outcomes. However, you should conduct visual, vacuum, or electrical tests to confirm the problem.

• Perform Tests To Confirm Egr Failure

The first step to repairing the failing EGR valve is locating and diagnosing the root cause. You can find the EGR valve location in your car’s manual. Usually, it lies next to the intake manifold, but the exact location varies in different cars.

The following points can tell you how to test EGR valve:

1. You can visually examine the valve. You must replace it if it looks damaged, has cracks, or smashed parts.
2. You can conduct a vacuum emissions test to detect a problem if your car has a vacuum-operated valve. Connect the pump to the valve with the engine off and apply vacuum. You might have a stuck valve if it does not hold the vacuum.
3. You should conduct an electronic test if your car has an electronic valve. Connect a multimeter to test the valve connections, and if the reading is out of the limit, repair the electrical parts.
4. Use a scan tool to check for EGR diagnostic codes. You can use the OBD-II scanner that indicates EGR flow or performance issues.

 

• Clean the Valve To Make It Work

Cleaning a clogged valve sometimes restores its function, so you won’t have to replace it. You should buy a good quality EGR or carburetor cleaner and a soft-bristled brush.

Make sure you disconnect the electrical power and remove the connectors if you have an electric valve. Then remove the bolts holding the EGR valve in its place by using a wrench or socket. It makes it easier to remove the valve, but you have to be careful so you don’t damage the hoses.

After removing the EGR valve, soak it in the cleaner for some time. You can spray more quantity on the areas with carbon buildup. The cleaner will soften the deposits, which you can scrub off later with a soft brush. Lastly, rinse the valve until all cleaner is washed away, and dry it using a cloth or air.

• Replace the Defective Valve To Restore the Function

If the EGR valve does not work even after cleaning and you’re wondering how to fix a faulty EGR valve, you should replace it. Before removing the valve, park on a flat road or surface.
Pulling out the EGR valve when the car is in a slanting position can result in fluid leakages. Also, let the engine cool down and remove the exhaust tube. Use sockets to disconnect so it hangs while you change the valve.

Remove the bolts or screws attaching the valve to the intake manifold. Keep the bolts because finding the same size can be tricky. Connect the new EGR valve and its gasket and secure them by putting the bolts back in their position.

In the end, attach the exhaust tube to the valve and test the car. You might have to drive your vehicle until the ECU detects the new part and stops EGR valve symptoms. The check engine light should turn off, and you will notice decreased fuel odor.

Once you know what damage can a faulty EGR valve cause, you will not delay the replacement. Your car will display higher emissions of harmful gasses. You will also notice increased fuel consumption, rough idling, overheating, and engine knocking.

The EGR valve replacement cost depends on the valve position in your car and labor cost. On average, buying the valve and getting it replaced costs around $200 to $600.

Conclusion

Now that you know all symptoms of a bad EGR valve and its causes, you can roll up your sleeves and apply the repair methods mentioned above.

The following points can help you with the process:

• A valve can get stuck open or close if it has a broken part or is exposed to high temperatures.
• A blocked valve, a damaged temperature sensor or solenoid, or mechanical defects cause EGR valve issues.
• After vacuum or emission testing, you can fix the EGR valves by cleaning or replacing them.

Following the recommendations in this article can help you reduce the harmful emissions from your car.