What are the causes of abnormal noise from the high-pressure fuel pump?
2 Answers
High-pressure fuel pump abnormal noise causes are as follows: 1. Cold start noise: When the car starts cold, the engine sound may be slightly louder than when the engine is warm. As long as the sound is uniform and soft, not harsh, it is generally not a problem. 2. Oil-related issues: It is necessary to add the appropriate type of engine oil. The high-pressure fuel pump is a lightweight and compact pump, which can be categorized into in-line, distributor, and unit types. It requires a power source to operate, with the lower camshaft driven by the engine crankshaft gear. The functions of the high-pressure fuel pump are: 1. Increase fuel pressure: It can boost fuel pressure to ensure complete combustion of the fuel. 2. Improve atomization effect: It achieves optimal atomization through high-pressure injection. 3. Serve as a power source: It can act as a power source for hydraulic devices such as jacks, heading machines, extrusion presses, and cotton gins.
When it comes to high-pressure fuel pump noise issues, I've seen way too many cases over my years as a mechanic. There are primarily three most common scenarios: First, when the clearance between the plunger and sleeve inside the pump wears out, it makes a clunking sound with each fuel pressurization - that's normal aging. Second, if the intake fuel line gets pinched or the filter screen gets completely clogged, starving the pump of fuel, it'll produce a painful squealing sound when running dry. Third, when the spring pushrod malfunctions and can't keep up with the return cycle, the entire pump makes hiccup-like thumping noises. The most frustrating culprit nowadays is some low-quality gasoline containing excessive water and impurities - forcing the pump to work like it's chewing sand, causing rapid wear and loud noise. My advice is to first check if the fuel lines are clear. If the noise increases with acceleration, you're almost certainly looking at needing a replacement pump.
