How to Guides

When and How to Service a Fuel Pump

Zaki Moulvi posted this on Jun 9, 2014

In a perfect automotive world, the gas tank would fit above the engine and the fuel would be able to use gravity to flow freely to your fuel injectors.  Obviously the automotive world is not perfect and a pump is necessary to move gas out of the tank and into your motor.  In the good old days of carburetors, the fuel pump was mechanical, durable and easy to access.  All of that changed with the introduction of fuel injection, and its demand for a highly pressurized supply of gasoline.

The trouble was, in order to meet the fuel injectors needs, an electronic fuel pump was required.  An electronic fuel pump that generated a tremendous amount of heat and noise when in operation.  Automotive design geniuses than came up with the solution to place this electronic pump in a convenient spot where liquid could keep it cool and stifle its noise.  This led to the placement of the modern day electronic fuel pump inside of the gas tank.

The new fuel pump design comes with a whole new set of problems.  The most obvious of course being accessibility.  Being controlled electronically as opposed to mechanically means more options to consider when attempting to diagnose a problem.  Plus, the fuel pump now has two primary functions, to push the gas to the fuel injectors and control the pressure needed to ensure that the right amount is delivered.  A malfunctioning fuel pump could interrupt either one, or both of these processes.

Common Malfunctioning Fuel Pump Symptoms

  • High speed sputtering.  This is when you are traveling at a consistent speed when your car will suddenly start to sputter, almost cough, for a mile or two before evening out again.  This type of vehicular behavior is indicative of a pressure problem with your fuel pump.  The car sputters as it is struggling to maintain the correct amount of fuel.
  • Loss of power during acceleration.  This will happen as you are trying to leave your driveway, or responding to a green light.  Your car is idling, you press the gas and the car jerks around, almost as if to stall and then suddenly corrects itself.  This means there is not enough gas at the combustion chamber, causing you to lose engine power.
  • Sudden surges forward.  A fuel pump that is on the fritz will sometimes get a sudden burst of energy that will cause your car to pick up speed unexpectedly.  This will usually only last a minute or two before it evens out and returns to your preferred driving speed.
  • A car that won’t start.  Of course the most common cause of a car that won’t start is a dead battery or broken starter.  To figure out if it is your fuel pump, turn the key to the start position without cranking the engine.  This should start up the fuel pump which you will hear as a clicking or buzzing noise coming from the gas tank.  If you don’t hear that sound, then there is no fuel getting to your engine.

Before running out to buy a new fuel pump, remember that this is an electrical component in your car.  Check the fuses and wiring first to be sure that the solution is not something simple.  If all of the electrical components seem to be in working order, then you should visit to order your new fuel pump.

The amount of work involved just to get to the fuel pump makes repairing one seem fruitless.  If one of the components has broken, it will only be a short matter of time before others follow suit.  Save yourself the time and headache now and just go ahead and replace the whole unit, once you know for sure that it is the cause of your car troubles.

Tools For the Job:

  • A large drain pan
  • Car jack
  • Wrench
  • Work gloves

Since there will be fuel involved obviously make sure your work place is well ventilated.

Accessing the Fuel Pump:

  • Disconnect the car battery.
  • Locate the drain plug on the bottom of your fuel tank.  Place the drain pan directly underneath and then open the plug and allow all of the fuel to flow in.  Once empty, replace the plug and store the pan of gas in a safe, cool spot, covered to prevent any dust or debris from getting inside.
  • Place the car jack underneath the fuel tank and raise it so that it can provide support.  With the wrench remove the mounting bolts and straps holding the tank in place and allow it to rest on top of the jack. 
  • Remove the fuel inlet hose from the tank, lower the jack and move the fuel out from beneath your car to a safe work area. 
  • The mounting bolts for the fuel tank will be on the outside of the tank, remove them and then carefully pull out the broken fuel pump.
  •  Assemble the new fuel pump by attaching the o-ring and then mount the piece inside of the fuel tank. 
  • Slide the tank back under the car, put the fuel inlet line back in place and reattach the tank to the undercarriage. 

Now all you need to do is replace the fuel, reconnect the battery and start her up.  Let it run for a few minutes, checking under the car for any leaks.  If all looks good, take the car for a few laps around the block to make sure that all of your prior issues are now resolved.  This DIY job sounds more complicated than it actually is.