If an engine shows 160 psi in three cylinders and 0 psi in one, what is the likely cause of the 0 psi in that cylinder?

The indication of 0 psi in one cylinder, while the other three indicate 160 psi, suggests that there is a significant issue affecting the compression in that specific cylinder. Given the options, interpreting the situation suggests faulty valve timing is a compelling reason for the loss of compression.

When the valve timing is incorrect, the intake and exhaust valves may not open and close at the appropriate times during the engine cycle. If the intake valve fails to open, the cylinder may not draw in the air-fuel mixture properly, or if the exhaust valve doesn't close, it can lead to a loss of pressure as the exhaust gases escape. Both scenarios can result in a cylinder showing 0 psi, highlighting the importance of proper timing for maintaining engine compression.

The other options would lead to compression issues but manifest differently. Piston ring damage typically causes a drop in compression but should show some pressure rather than 0 psi. A leaking head gasket may cause low compression due to coolant intrusion, which could result in a lower psi reading rather than a complete lack. Clogged fuel injectors primarily affect fuel delivery, which can impact performance but wouldn't directly result in 0 psi in a cylinder during a compression test.