Why does the tensioner pulley keep failing?

[Doug]

Tensioner pulley failure can cause the engine timing to skip teeth. Tensioner pulley damage: A failed tensioner pulley can cause the engine timing to skip teeth, leading to ignition and valve timing disorders, engine shaking, difficulty starting, and in severe cases, failure to start. After starting, it may deform the valves. It is recommended to replace it as soon as possible. Symptoms of damage: Symptoms of a damaged tensioner pulley include sudden increase in engine noise during rapid acceleration (especially around 1500 RPM), engine timing skipping teeth, ignition and valve timing disorders, engine shaking, and difficulty starting (in severe cases, complete failure to start). If these symptoms occur, the tensioner pulley should be checked for damage.