What causes a cylinder to extend but not retract?

[HavenAnn]

Cylinders failing to retract after extension are generally caused by spark plug failure, excessive fuel injection, or insufficient cylinder pressure, and require prompt inspection at a 4S shop to diagnose and resolve the issue. Below is relevant information about automotive engine cylinders: Classification: Based on the arrangement of engine cylinders, they can be categorized into L-type in-line, V-type, H-type horizontally opposed engines, and W12/16-type engines. Engine displacement equals the sum of the working volumes of all cylinders. Increasing the number of cylinders can enhance engine displacement, boost engine output power, and improve engine smoothness while reducing vibrations and noise. Number of cylinders: Common cylinder counts for automotive engines include 3, 4, 5, 6, 8, 10, and 12 cylinders, with 4-cylinder and 6-cylinder engines being the most prevalent, and 4-cylinder engines being the most widely used. Nowadays, engines with displacements below 1.3 liters often feature three cylinders, 1.5–2.5-liter engines typically have four cylinders, around 3-liter engines usually have six cylinders, approximately 4-liter engines have eight cylinders, and engines above 5.5 liters use twelve cylinders.