While the mechanic may have replaced the fuel pump, there could still be other reasons for the humming noise coming from the fuel tank of your 1993 Toyota Tercel. Here are a few possibilities to consider:
1. Fuel Filter:
- A partially clogged or dirty fuel filter can restrict fuel flow and cause the fuel pump to work harder, resulting in a humming noise. Check the fuel filter and replace it if necessary.
2. Fuel Lines:
- Kinks or bends in the fuel lines can also create a humming noise as fuel flows through them. Inspect the fuel lines for any damage and ensure they are routed correctly.
3. Fuel Pressure Regulator:
- A faulty fuel pressure regulator can cause fuel to flow back into the tank, creating a humming sound. Check the fuel pressure regulator and replace it if it is malfunctioning.
4. Faulty Fuel Tank Sending Unit:
- The fuel tank sending unit is responsible for measuring the fuel level in the tank and sending the information to the fuel gauge. A malfunctioning sending unit can cause the fuel pump to run continuously, resulting in a humming noise. Check the sending unit and replace it if necessary.
5. Loose Fuel Tank Strainer:
- The fuel tank strainer is a small filter located inside the fuel tank. If it becomes loose, it can vibrate and cause a humming noise. Check the strainer and make sure it is securely fastened.
6. Electrical Issues:
- In rare cases, a humming noise coming from the fuel tank can be caused by electrical issues, such as a loose ground connection or a short circuit in the fuel pump wiring. A qualified mechanic can diagnose and resolve any electrical problems.
7. Incorrect Fuel Pump Installation:
- Although it's unlikely if the mechanic performed the fuel pump replacement, an incorrectly installed fuel pump can also cause humming noises or improper functioning of the fuel system.
Recommendation:
Given that the fuel pump has already been replaced, I recommend that you have a trusted mechanic conduct a thorough inspection of the fuel system to identify and address the root cause of the humming noise. This will ensure that the problem is resolved effectively.
