Why is there no sound from the fuel pump during car self-check?
4 Answers
The fuel pump should make a sound near the fuel tank when the ignition switch is first turned on. High-pressure fuel pump explanation: The high-pressure fuel pump requires a power source to operate, with the lower camshaft driven by the engine crankshaft gear. The fuel pump features a housing made of aluminum-containing material and a movable molding component inside the housing, which is at least partially made of a sinterable, iron-based alloy material containing austenite. Precautions for using the fuel pump: During use, it is strictly prohibited to dilute gear oil with diesel or other substances. Also, avoid heating the rear axle or transmission to facilitate winter starts, as this may severely degrade the gear oil. In such cases, switch to a low-viscosity multi-grade gear oil. Do not confuse the classification labels of engine oil and fuel pump. To avoid confusion in standards, higher classification labels are designated for gear oil, while lower ones are used for engine lubricants.
I've encountered this situation quite often. If you don't hear the fuel pump humming during the car's self-check, it's likely due to an issue with the fuel pump system. Usually, it's a blown fuse – this is easy to check. Just open the fuse box and look for any signs of melting on the fuse marked for the fuel pump, then try replacing it with a new one. If the fuse is fine, the relay might be faulty. The relay is a small component that controls the power supply to the fuel pump, and aging or a short circuit can cause the fuel pump to stop responding entirely. Additionally, the fuel pump itself might be worn out or stuck, especially in older cars or those frequently left idling. A fuel pump typically lasts just over 100,000 kilometers before needing replacement. Wiring issues are also common, such as loose connectors or corroded wires, preventing current from reaching the fuel pump. For safety, it's best not to force-start the engine to avoid the risk of the fuel pump failing completely and causing a breakdown. A reliable repair shop can quickly diagnose the problem using a diagnostic tool.
I had a similar issue with my car once—the fuel pump was silent during self-check. First, I checked the owner's manual to locate the fuse and found it intact. Then, I listened near the trunk for any vibration sounds. Relays are usually in the engine bay or under the seats; give them a light tap to check for looseness. If all seems fine, the fuel pump might be dead. Don’t rush to a repair shop—you can buy and replace it yourself, though it’s more labor-intensive. Remember, a silent fuel pump affects ignition, so ensure the tank isn’t empty before starting. Using quality fuel regularly extends part lifespan. DIY within your skillset, but don’t delay if stuck, or the engine may fail to start, causing bigger issues.
A silent fuel pump directly affects driving safety. If it doesn't make noise during self-check, it means the pump isn't moving fuel, and engine ignition will definitely fail - being stranded on the road would be troublesome. Common causes include short circuits or blown fuses, especially in modified vehicles which are more susceptible. Don't risk multiple startup attempts to avoid worsening damage. Regular maintenance checks of the fuel system are crucial, and listening for pump sounds can help predict issues. If ignored, a sudden fuel pump failure during highway driving becomes even more dangerous. I recommend immediately pulling over to a safe location for troubleshooting or seeking professional mechanic assistance.
