What are the symptoms of a faulty exhaust gas recirculation valve?
2 Answers
Symptoms of a faulty exhaust gas recirculation valve include: unstable idle, poor acceleration, increased fuel consumption, and insufficient power. The main purpose of exhaust gas recirculation is to reduce nitrogen oxides in the exhaust gases and improve fuel economy under partial load conditions. There are two types of exhaust gas recirculation systems: mechanically controlled EGR systems and electronically controlled EGR systems. The troubleshooting methods for exhaust gas recirculation system faults are: 1. Start the engine and let it reach normal operating temperature, then press the accelerator pedal to raise the engine speed to over 2000 rpm; 2. If the EGR valve lever does not move, turn off the engine and manually move the lever to check if it moves freely. If it cannot move, remove the EGR valve for cleaning. If it still cannot move, replace it with a new EGR valve; 3. If the EGR valve lever can be moved manually, start the engine, disconnect the vacuum hose on the EGR valve, and use a vacuum gauge or your finger to check for vacuum suction. If there is no vacuum suction, it indicates a fault in the EGR control part, which should be further inspected.
I suspect the EGR valve is malfunctioning. Common symptoms include noticeable engine shaking, with the car vibrating severely at idle—almost like it's dancing. There's also a lack of power during acceleration, with sluggish response when pressing the throttle, and fuel consumption spikes significantly. On long trips, I've spent much more on gas than usual. The check engine light often stays on, and the dashboard warns of a system fault. Black smoke from the exhaust is also common, indicating incomplete combustion. Starting the engine may be difficult, and it might even stall unexpectedly at traffic lights. Most of these issues arise from a clogged or leaking valve, preventing proper exhaust gas recirculation and disrupting engine breathing. It's best to visit a professional repair shop promptly for inspection and replacement of faulty parts—don't wait for minor issues to escalate into major failures.
