What Causes Abnormal Engine Noise During Acceleration?
2 Answers
Abnormal engine noise during acceleration is caused by irregular engine speed conditions during operation. Below are the specific reasons for abnormal engine noise: 1. Noise occurs only at idle or low-speed operation: Excessive clearance between the piston and cylinder wall; Over-tight piston pin assembly or connecting rod bearing assembly; Excessive clearance between the tappet and its guide hole; Wear on the camshaft profile; Sometimes, a loose starter clutch causes pulley noise (noticeable during speed changes). 2. Noise becomes chaotic at a certain speed, with brief sounds emitted during rapid deceleration: Cracked camshaft timing gear or loose fixing nut; Broken crankshaft; Loose piston pin bushing; Excessive axial clearance of the camshaft or loose bushing. 3. Noise appears during rapid engine acceleration and persists at high-speed operation: Loose connecting rod bearings, melted or incorrectly sized bearing shells causing rotation; Loose crankshaft bearings or melted bearing shells; Broken piston pin; Broken crankshaft.
When you stomp on the accelerator while driving and hear a metallic ticking sound from the engine compartment, especially more noticeable when going uphill, this is usually a knocking phenomenon. The difference between domestic 92/95 gasoline grades is significant, with lower-grade gasoline having poor anti-knock properties. Combined with carbon deposits in the cylinders forming hot spots, it can easily cause pre-ignition. Additionally, leaks in the intake and exhaust systems can produce a hissing sound, such as loose turbocharger pipe joints. Last week, I helped a friend troubleshoot a similar issue and eventually found that his long-term use of 92-octane fuel from small gas stations caused a leaking sound near the catalytic converter. Switching to 95-octane fuel from a reputable gas station made a big difference. If you encounter this situation, don't push it; go to a chain auto repair shop for a free inspection first.
