What Causes Abnormalities in the Engine Fuel Supply System?
3 Answers
Causes of abnormal fuel supply in a car engine are as follows: 1. Clogged air valve or vapor valve in the fuel tank cap. 2. Clogged fuel filter. 3. Damaged fuel pump: failure of inlet and outlet valves, ruptured diaphragm, excessive clearance between outer and inner rocker arms. 4. Air or fuel leaks in the fuel system, dented or clogged fuel lines. 5. Water in the fuel lines. 6. Vapor lock. Repair methods include: 1. Measuring fuel pressure. 2. Removing and inspecting fuel injectors. Check each injector for leaks. Clean or replace injectors if abnormalities are found. 3. Inspecting the ignition system. Check ignition voltage and energy, as well as ignition timing. 7. Clogged carburetor fuel inlet or filter screen. 8. Clogged carburetor fuel passages or stuck inlet needle valve.
I've been in the auto repair industry for over a decade, and the most common causes of fuel delivery system issues in engines include fuel pump failure or insufficient power, especially in older vehicles, as the motor inside the pump tends to wear out. Next is a clogged fuel filter, where accumulated impurities in the fuel restrict smooth fuel flow, leading to poor fuel delivery. Injector carbon buildup or sticking is also a major problem, causing uneven fuel spray or no fuel delivery. Additionally, a faulty fuel pressure regulator can't maintain proper fuel pressure, often resulting in the fuel light staying on the dashboard. Wiring issues like poor connections or short circuits, particularly in humid environments, are also culprits. If you notice symptoms like weak acceleration, severe shaking, or unstable idling, it's likely a fuel delivery problem. Don't delay inspection and repair to avoid breaking down on the road.
Last month, I just encountered this issue. While driving, the engine suddenly jerked. Upon inspection at the repair shop, it turned out that the fuel filter in the fuel tank was completely clogged with too much dust. Carbon buildup in the fuel injectors was also one of the reasons—too much dirt prevented proper fuel injection. The fuel pump had aged, causing slow fuel delivery. Electrical issues, such as sensor failure or loose wiring, could also cause malfunctions. I also learned that regularly changing the air filter can reduce impurities entering the fuel system. If you encounter abnormal fuel supply, don’t panic. First, pull over safely and check the fuel level in the tank. After ensuring safety, seek professional help as soon as possible.
