What Causes the Ticking Sound When Accelerating but Not at Idle?

[OKinsley]

The reasons for the ticking sound when accelerating but not at idle include: 1. Check if the pipe near the coolant reservoir is rubbing against the reservoir. 2. Inspect whether there is resonance in the fuel supply line. 3. Abnormal noise from the fuel line. 4. If the noise comes from the upper part of the engine (valve-related), common causes are: overly advanced ignition timing; low fuel octane rating; incorrect air-fuel mixture ratio; damaged valve lifters (hydraulic lifters). This will not cause cylinder scoring. 5. If the noise originates from the middle or lower part of the engine, possible causes are: excessive clearance between the piston pin and piston (connecting rod); excessive piston ring gap; excessive clearance between the connecting rod and crankshaft. This situation can lead to cylinder scoring. 6. If the noise is from the front part of the engine, possible causes are: loose or worn timing chain; damaged tensioner. A broken or skipped timing chain can cause the valves to collide with the pistons, resulting in valve breakage, piston damage, bent connecting rods, cylinder block damage, and cylinder head damage.