How to Check a Bad Electric Fuel Pump

  • 0.5-1
  • Beginner
What You'll Need
2 jumper wires
Voltage tester

An electric fuel pump is an integral part of the vehicle. It aids in the pumping of fuel from the gas tank to the engine. The pump is usually located next to the fuel tank and it is very easy to check whether it is faulty. All you need is to follow a few steps as outlined below.

Step 1 - Insert Key into Ignition

Take the car key and put it into the vehicle ignition. Turn the key to the second position, which does not crank the engine but only lights the dash lights. The vehicle should produce a soft sound from the back immediately you turn the key. The sound comes from the fuel pump, as it gets ready to draw fuel and pump to the engine. If the vehicle does not produce this sound, then the fuel pump may be bad.

Step 2 - Start the Vehicle

Even with the absence of the soft sound, start the vehicle to confirm whether the pump is bad. When you have a defective electric pump, the vehicle will crank but the engine will not start. The car may start but the pump may produce an abnormal loud sound, which will indicate that it is faulty. A bad fuel pump will also overheat quite frequently. On turning on the vehicle, the pump heats very fast, indicating that it is not functioning properly. When the fuel pump is defective, the vehicle experiences intermittent breakdowns and then restarts after cooling down for some time.

Apart from these instances of stalling, the car may also experience instances of sudden acceleration caused by engine surging, when a faulty fuel pump supplies the engine with too much fuel. Your vehicle may also fail to accelerate smoothly when the fuel pump is faulty and does not provide a continuous flow of gas into the engine. In addition, an impaired fuel pump makes the car sluggish when climbing hills because it does not supply enough fuel to power the car up the hill.

Step 3 - Check for Fuel

Your vehicle may experience the above problems for the simple reason that there is no fuel in your gas tank. The pump does not draw enough from the tank to supply the engine through the fuel system. This may cause the pump to produce the loud humming sound besides stalling along the way. Replenish your vehicle’s fuel tank and restart it, checking for all of the above signs of a bad pump. If you still experience the same problems, then you will confirm that your electric fuel pump is indeed bad.

Step 4 – Check the Pump Electrical Mechanism

Open the fuse box of your electric fuel pump and locate the fuse. Check whether the fuse has blown off. If it has this may be the cause of your dysfunctional fuel pump. Replace the fuse and test the vehicle again to see that it runs without any hitches. If the vehicle still has problems, then your electric fuel pump may be faulty.