What are the symptoms of a faulty wastegate valve?

[LeEmmanuel]

Here are the symptoms of a faulty turbocharger wastegate valve: 1. When the boost pressure in the compressor exceeds the predetermined value: The air pressure pushes the diaphragm to compress the spring, causing the push rod to extend outward and open the wastegate valve. This diverts part of the exhaust gas away from the turbine, allowing it to enter the exhaust pipe directly through the bypass valve installed before the turbine. This reduces the amount and pressure of exhaust gas driving the turbine, thereby lowering the turbine speed and boost pressure, preventing engine overspeeding due to "over-boosting". 2. When the compressor pressure drops to a certain level: The pressure above the diaphragm is insufficient to overcome the spring force, causing the spring to rebound and move the linkage to close the wastegate valve. All exhaust gas then drives the turbine again, increasing the boost pressure until the next time the wastegate valve opens. This cycle continues, keeping the engine's boost pressure controlled at a fixed value.