Fuel pumps, only have one important job, and that is, to deliver fuel from the tank to the engine.

So, in the old days, with carbureted systems, most pumps were only mechanical.

But, today, with electronic fuel injection systems, they require higher fuel pressures. And, are only accomplished, in part, by using an electric pump.

Consequently, the location of fuel pumps has changed over the years as well.

Meanwhile, an older, inline mechanical pump, was mounted on the engine. So, the pump moves, as your camshaft spins and fuel is drawn, through a line using suction. However, today fuel injection systems, have the pump mounted, inside the fuel tank.

Fuel travels through the fuel line and toward the carburetor or the cylinder:

  • So, in a carbureted engine, fuel is injected with air and forms, a mixture in the carburetor.
  • However, in a fuel-injected engine, fuel and air don’t mix, until they reach the cylinder.

Common Failure Signs Include:

  • Difficulty Starting The Engine
  • Whining Noise From the Fuel Tank
  • Engine Sputters or Surges
  • Loss of Power Under Load
  • Reduced Gas Mileage
  • Stalling at High Temperatures
  • Increased Engine Temperature

So, diagnosing a fuel-related no-start problem, takes some skills. Consequently, there are many other things, that may prevent a good pump from working. For example, a bad fuel pump relay, a tripped inertia safety switch or even a problem with the anti-theft system. And, can also include, a plugged fuel filter, fuel line, faulty fuel pressure regulator or fuel pump control module.

Finally, the pump is not part of a regular maintenance schedule. Therefore, only when it fails, it will need replacement. But, most pumps should last, well past 100,000 miles.

Choose Your Help Topic Below

Failure – Warning Signs – Common Causes – Failure Symptoms

Common Issues – Excessive Heat – Contamination From Dirt and Rust

Fuel Pump Related No Start Problems – What Should You Check

Electric Fuel Pump – How Do They Work – How Can They Fail

Related Problems – Not Always Easy To Solve

Hard Starting Engine – Cold, Hot, Both Or Just After Refueling

Engine Fuel System Testing – Proper Testing With Solutions

Mechanical Pump – Basic Information And Troubleshooting

Fuel Pump Diagnosis Tips from Carter (PDF file – requires Adobe Acrobat Reader to view).

Thank You !