What Causes the Abnormal Noise When Accelerating the Engine?
4 Answers
Engine buzzing noise may be caused by engine failure or exhaust pipe leakage. Here are the specific details: 1. One situation that can cause engine buzzing is when the car is in the wrong gear while driving. A mismatch between the car's speed and gear can lead to engine buzzing, but this is not an engine fault. The noise will disappear when the car's speed matches the gear. 2. During driving, the engine's load increases, requiring the throttle opening to be increased and more fuel to be supplied. If the throttle is dirty or not opened to the optimal position, it can result in poor mixture ratio inside the engine, causing a buzzing noise during acceleration.
Last time I drove an old Ford Focus, I encountered a similar situation - a rattling sound came from the engine bay when stepping on the gas. Such issues are usually caused by a loose or aged/cracked belt, with the rubber friction noise being particularly noticeable. If it's a metal scraping sound, the tensioner pulley bearing is likely gone. I specifically asked a mechanic, who said some cars produce metal knocking sounds during hard acceleration - that's a detonation issue requiring spark plug and carbon deposit inspection. The most concerning is that clattering metal sound, which in nine out of ten cases indicates a stretched timing chain. Additionally, turbocharged cars may produce a whistling noise, most likely due to turbocharger seal leakage. Don't push through these situations - get it checked immediately. Last time I delayed too long and ended up spending an extra 800 yuan to replace the belt assembly.
I have plenty of experience with acceleration noises. My Accord went through the exact same issue last year. It would make a squealing sound when climbing hills with the AC on, and later I found out it was a failed alternator bearing. These noises come in several types: high-pitched squeaks usually indicate belt problems, gurgling sounds like boiling water mean the water pump is failing, and clunking noises are often due to worn engine mounts. A whistling sound suggests an exhaust manifold leak, while loose exhaust hangers produce metallic rattling. If there's a swishing noise from inside the engine, it's likely a valve lifter issue. I recommend getting the car lifted at a repair shop for diagnosis - last time I paid just $50 for inspection and confirmed the problem, then spent about $200 replacing the bearing.
Our fleet's diesel trucks often experience abnormal noises during acceleration, with different sounds indicating different issues. A noticeable ticking sound when pressing the accelerator hard is usually due to a faulty diesel injector. If there's a metallic clanging sound like hammering on iron, it's likely excessive wear on the connecting rod bearings. From my ten years of driving experience: the most common is the hissing sound from loose belts; sharp metallic friction points to the water pump; a dull clunk suggests checking the engine mounts; sudden ticking warns of timing chain issues. Especially if it becomes more noticeable after turning on the AC in summer, prioritize inspecting the alternator tensioner. Veteran drivers know these abnormal sounds are the vehicle's early warning signals.
