The most common symptoms of a bad exhaust gas recirculation valve are rough or misfiring idle, detonation, stalling and hard starting. The EGR valve is a component of an automobile’s exhaust circulation system that reduces pollution-causing emissions.Continue Reading
When an EGR valve functions incorrectly by leaking, becoming clogged or otherwise malfunctions, it results in poor engine performance. Because many EGR valves are mechanical, they are prone to becoming stuck in opened and closed positions. EGR valves that are stuck open cause poor idling, engine misfiring and stalling. If the valve is stuck closed, a nitrogen oxide builds up resulting in knocking and incorrect engine timing.
Mechanics can look for other causes by using a vacuum gauge to check for sufficient vacuum supply. No vacuum indicates a leak in the system. Mechanics can also examine the EGR valve stem to see if it moves while the engine is revving. If it does not move, the valve is bad and needs to be replaced. The valve also needs to be inspected for clogs and cleaned or replaced, if necessary.
Because EGR valve problems have a number of causes, the best way to diagnose the issue is to use a scanning tool that displays trouble codes. Vehicle service manuals list the proper repair protocol depending on the trouble codes.Learn more about Car Parts & Maintenance
To replace an exhaust gas recirculation valve, the emissions system should be tested, the vacuum line removed and the unit replaced. The unit is generally mounted on or near the intake manifold of the vehicle.Full Answer >
The most common symptoms of a defective ignition module are overheating, unexpected stalling or inability to start the vehicle. Replacing the module is an expensive process, and checking the circuits, electrical connections and temperature issues within the first or second occurrence of stalling can save time and money.Full Answer >
Fuel leaking from near the tailpipe and black smoke coming from the vehicle's exhaust system are both common symptoms of a bad fuel pressure regulator. A worn out or faulty regulator may also cause the check engine light to turn on or the engine compartment to smell of gasoline.Full Answer >
One of the most common symptoms of a bad throttle body, or throttle position sensor, according to Reference, is when the car either hesitates to accelerate or stumbles during acceleration. If there seems to be just a bit of a delay between the time you push on the gas pedal and the time it takes for the car to go, a bad throttle body could be the cause.Full Answer >