Types of Fuel Pumps

• In older automobiles, the fuel pumped was usually attached to the engine or to the frame between the fuel tank and the engine. In newer automobiles, the fuel pump is usually inside the fuel tank. Modern fuel pumps are electric and are therefore part of the electrical system of the car that is controlled by computers This makes them more efficient than mechanical pumps but prone to more difficult problems.
  
  

Strange Sounds

• One way of diagnosing a fuel pump problem is by the sounds that a malfunctioning fuel pump makes. Since the fuel pump is electrical you can hear it when you turn the car on. If it is excessively noisy this may indicate that there is a clog in the fuel filter. If it becomes loose or is not attached properly in the fuel tank, you may hear the fuel pump touching the metal inside the tank. In the first two cases the sound indicates a minor problem. However, excessive noise may indicate that the fuel pump is failing.
  
  

Relay Switch Problems

• Problems with the relay switch are common to fuel pumps. The relay switch is energized for a few minutes so that the fuel pump will run up to pressure. If you hear the fuel pump continue to run when the engine is turned off, the relay switch is probably stuck and needs to be replaced.
  
  

Contamination Problems

• Rust and dirt pay get through the very filter that is designed to keep them out. The fuel tank itself may be dirty and have rust in it. This will contaminate and degrade the fuel pump, causing it to break down. The motor eventually overheats and wears out.
  
  

Electrical Problems

• Electrical devices wear out. Wear and tear on the brushes and bearings eventually stops a fuel pump from working. The roller gears can also be worn down. Fuel pumps are kept cool and lubricated by the proper amount of fuel running through them. If they are not receiving the proper amount of fuel they may break down prematurely. If the voltage is low or weak, the fuel pump will not function properly.