7 Symptoms of a Bad EGR Valve
Exhaust gas recirculation is a process that has been used to reduce emissions since the 1970s. Exhaust gas recirculation (EGR) systems redirect some of the exhaust gases back into the intake manifold so they can re-enter the combustion chamber.
It may sound strange, but this emissions-reducing process actually provides many tangible benefits to your engine.
This translates into improved fuel economy. Newer EGR systems can also reduce temperatures inside the combustion chamber by cooling the exhaust gases.
What is an EGR valve? The purpose of this valve is to help recirculate the engine’s exhaust gases by directing them back into the combustion chamber instead of out the exhaust or tailpipe.
All of a vehicle’s exhaust gases rely on the EGR valve to control their flow. The EGR valve works in conjunction with the EGR system to accomplish this. This means that the EGR valve remains closed at idle and wide open throttle to prevent these exhaust gases from entering the combustion chamber.
A faulty EGR valve may prevent it from opening and closing properly. You may not realize this until you notice more obvious symptoms.
Most Common Symptoms of a Bad EGR Valve
Here are some of the most common signs that indicate a bad EGR valve.
1) Check Engine Light
If your EGR valve is defective or has failed, it may cause the check engine light to come on in your dashboard. This happens as soon as your vehicle’s central computer detects that the EGR valve is in an abnormal position. For example, if the EGR valve doesn’t close all the way, or doesn’t open all the way when it should, the computer will detect that something is wrong and turn on the Check Engine Light.
2) Reduced Engine Performance
Having the valve open at full throttle means less combustible air in the engine when you need it most.
A defective EGR valve can lead to engine performance problems. You may experience difficulty accelerating when you step on the gas, or an overall loss of power. This is because the air-fuel ratio is not correct.
As a result, your engine needs more fuel to produce power. This means more fuel consumption and less fuel economy, which means you end up spending more money on gas.
3) Fuel Odor
This can make the fuel smell so strong that passengers can smell it from inside the car. Of course, you don’t want to keep smelling this odor all the time, as it’s not good for your health. So this is motivation to address the EGR valve issue immediately.
4) Rough Idling
If a faulty EGR valve gets stuck in the open position, it can cause the engine to idle rough. EGR systems are not designed to recirculate at idle, as this can lead to unstable combustion. This is very noticeable if you’re expecting a smooth idle.
5) Failed Emissions Test
If you live in a state that requires you to have an emissions test every few years, failing this test could indicate that you have a bad EGR valve. This won’t necessarily be obvious to you, but if it’s not working, it’s something to look out for.
6) Engine Knocking
Most EGR systems are cooled. If the EGR system loses coolant, it can cause engine knocking or premature detonation. Knocking often occurs when the intake temperature is too high, the air-fuel ratio is wrong, the ignition timing is too aggressive for the ambient conditions, or there is too much carbon buildup in the intake system.
7) Swollen or Stalled
This can cause surging or stalling when accelerating. This can also trigger the vehicle’s limp or failover mode.