Which condition indicates a potential overboost situation in turbocharged engines?

A stuck closed wastegate is a critical condition in turbocharged engines that indicates a potential overboost situation. The wastegate is designed to regulate the amount of exhaust gas that bypasses the turbine wheel in the turbocharger, controlling boost pressure. When the wastegate is functioning properly, it opens at a predetermined boost level, allowing excess exhaust to divert and limiting the boost pressure to a safe level.

If the wastegate becomes stuck closed, it prevents the necessary exhaust gas from bypassing the turbine. This results in an increase in boost pressure beyond the intended limits, which can lead to knocking, detonation, or potentially severe engine damage due to excessive pressure. Monitoring boost pressure and ensuring the wastegate operates correctly is crucial for maintaining the health and performance of turbocharged engines. In contrast, other options may lead to various performance issues or restrictions but do not specifically indicate an overboost scenario as directly as a stuck closed wastegate does.