What Causes a Fuel Pump to Go Bad? (4 Common Reasons)

Fuel pumps pull gasoline out of the fuel tank and pump it into the engine. A good fuel pump maintains a bit of pressure so there is always an adequate supply of fuel, no matter how much you press the throttle.

Over time, fuel pumps can go bad for a number of reasons. Did you know there are some things you as a driver could do to cause your fuel pump to fail prematurely?

Related: Symptoms of a Bad Fuel Pump

Why Do Fuel Pumps Fail?

With proper care of the fuel system and good fuel, a fuel pump should last at least 100,000 miles, and sometimes several times that. There usually isn’t a regular maintenance interval, though you can always check the owner’s manual just to be sure.

Here are some common things that cause a fuel pump to go bad.

1) Age-Related Degradation

keep an old car

Even with the best care, most parts will eventually wear down and break. This isn’t an inherent fault of yours or the manufacturer’s; most components are built with a specific service life in mind.

2) Bad or Improper Fuel

signs of bad gasoline

Contaminated fuel is one of the leading causes of premature fuel pump failure. If the fuel filter hasn’t been serviced as often as it needs to be, dirt and debris may enter the fuel pump itself.

This causes additional wear on the fuel pump. Either the fuel pump has to work harder to overcome the resistance of the debris, or the debris damages the pump itself.

Not all fuel is created equal. Besides choosing the correct octane rating of gasoline, it’s a good idea to select a good gas station for the best chance of having quality fuel. While any station can have a batch of bad gas, it may be more likely at some than at others. 

Contaminants or water in the fuel can clog the fuel filter which puts more stress on the fuel pump. In the same way, be careful of additives for the tank. Use only well-known and mechanic-recommended fuel system additives.

Using the incorrect type of fuel is a quick way to cause problems with the fuel pump. Never put diesel into a gasoline-powered vehicle, or vice versa. This is a good way to destroy your fuel system and potentially the engine.

Running ethanol in a vehicle that was not designed for it may cause problems with the fuel pump depending on the concentration. Low concentrations of ethanol (about 10%) are present in most modern fuels. E10 gasoline is compatible with most modern gasoline fuel systems.

Related: Ethanol vs Non-Ethanol Gas (Comparison)

3) Driving on an Empty Tank

bad fuel economy

It’s important to drive the vehicle with at least 25% of the tank full in order to properly cool the fuel pump. If you drive around frequently with less than a quarter tank of fuel, the fuel pump is in danger of damage from overheating and may fail prematurely.

The fuel pump is immersed in fuel and uses this fuel to cool the unit. Low fuel levels will raise the temperature of the fuel in the tank and in the fuel pump. Additional heat means additional wear.

When the fuel level is low, you are also more likely to draw sediment from the bottom of the tank. This could saturate the fuel filter with buildup prematurely, or the sediment could even get transferred into the fuel pump itself.

4) Clogged Fuel Filter

Your fuel filter has an important job, filtering out debris and contaminants such as dirt and rust particles which can accumulate in the fuel pump. As these contaminants build up, they can clog the fuel strainer and prevent the pump from drawing enough fuel to function properly, leading to fuel pump failure.

What Happens When My Fuel Pump Fails?

If your fuel pump goes out, you will most likely be stranded. A fuel pump may cut out intermittently or fail completely where you will be unable to run the vehicle at all. An intermittent fuel pump failure would look like a stalling engine, which may get progressively worse over time.

How to Tell if Your Fuel Pump Died

bad fuel pump symptoms

Diagnosing a failed fuel pump is typically fairly straightforward. Here are some things you can check to speed up the process.

1) Listen for the Buzz

When you first turn the key (or open the door, in some models), you will hear a quiet humming or buzzing sound. This is the fuel pump operating to prime the fuel system. Some fuel pumps are very quiet and you may not hear them.

If you normally hear a hum or buzz and stop hearing it one day, you may have a bad fuel pump.

2) Check Fuel Pressure

When you crank the engine, you should have fuel pressure. You could perform a fuel pressure test while cranking the engine to make sure you have fuel pressure. If you have no fuel pressure, there is very likely a problem with the fuel pump.

3) Check Your Fuses and Relays

fuse box

To avoid an unnecessary fuel pump replacement, inspect your fuses and relays to make sure all are good. It is especially important to check those fuses and relays related to the fuel pump. A bad fuse or relay would exhibit the same symptoms as a fuel pump that stopped working entirely.

Preventing Fuel Pump Issues

Regular Maintenance

To prevent fuel pump failure, regular vehicle maintenance is important. Here are some fuel-related areas to address:

  • Change your fuel filter at the manufacturer’s recommended intervals to avoid clogging the filter with rust, dirt, and other contaminants.
  • Inspect the filter sock, which is often located at the bottom of the fuel pump. Replace the filter sock if it becomes dirty or damaged.
  • Keep an eye out for rust contamination in the fuel tank, as this can also lead t problems.
  • Have a professional check the fuel lines for any signs of damage, such as cracks or leaks, which could allow moisture and contamination to make its way into the fuel system.

Proper Fueling Practices

To maintain your fuel pump’s longevity, follow these tips when filling up:

  • Always try to keep your fuel tank at least 1/4 full. Running on low fuel levels can cause the fuel pump to overheat, reducing its lifespan.
  • Stick to gas stations that use top-tier fuel as this minimizes your chance of using low-quality gasoline or gasoline with excessive water content.
  • In case of moisture or condensation problems in the tank, consider using a fuel additive that helps absorb and remove moisture from the system.

Good Fuel Filtration

  • Invest in a high quality fuel filter to protect your fuel pump and engine from various contaminants.
  • Check and replace your fuel filter according to manufacturer recommendations to prevent clogs and other issues.
  • Periodically inspect your fuel lines and other fuel system components for signs of wear or possible contamination.


While fuel pump failure isn’t terribly common, it does happen and is more likely to occur on vehicles that are run below a quarter tank of fuel on a frequent basis.

In order to avoid fuel pump issues, make sure you’re using clean gasoline, changing the fuel filter regularly, and keeping the fuel level above a quarter tank.


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