How You Can Tell If Your Fuel Pump Is Bad


One of the things we take for granted on our cars is our engine working without any issues. Despite it being a complex machine with multiple moving parts, we expect it to just work.

Whether you’re driving to work, the store, or the gas station, there are a lot of things going on behind the scenes.

One of the most fundamental is fuel moving from the fuel tank, through the fuel lines, and into the engine where it’s combusted in order to drive your car foreward.

To make that happen though, you need a working fuel pump.

The often forgot about fuel pump is a mainstay on nearly all internal combustion engines, minus some older engines which are often found on motorcycles.

What The Heck Is Your Fuel Pump? (Hint: Your Vehicle Won’t Run Without It)

Your fuel pump either sits in your fuel tank directly, or just outside the tank itself and is responsible for drawing the fuel from your tank, and then feeding it into the fuel line which takes the fuel itself to the engine.

Your fuel pump also filters out nasty impurities in your gas tank before sending the fuel itself to the engine. There’s also a fuel gauge that attaches to the fuel pump which is quite literally afloat. By floating around in your gas tank, it gives you a fuel reading on your dashboard.

There are two types of fuel pumps, the electronic fuel pumps found on newer vehicles, and the mechanical ones found on older models.

The first electronic fuel pumps came under development in the late 1920s, and started to be integrated into US vehicles in the 1950s, with it becoming commonplace by the late 1980s into the 1990s.

The electronic fuel pump uses an electromagnetic switch in conjunction with a diaphragm to provide suction in order to pull the fuel into the chamber.

A mechanical fuel pump uses a similar diaphragm and valve as the electric fuel pump, but it’s driven by either the camshaft or by a special shaft that runs off of the crankshaft.

The good news is both fuel pump types are fairly reliable, and they often last over 100,000 miles.

The bad news is they do go out, and when they do, your car isn’t going to be going anywhere fast.

To be honest, it won’t be going anywhere at all!

Your Fuel Pump Will Last An Average Of ~100,000 Miles

The average fuel pump will last for about 100,000 miles, although I’ve seen my fair share of cars that still have their original fuel pump working just fine even after 200,000 miles. So why do some fuel pumps last longer than others?

There’s a few reasons. Generally speaking, if you use higher quality gas and keep the tank at least a quarter full or more, you can expect your fuel pump to last longer all things equal.

Here are my reccomendations to keep your fuel pump running for as long as possible:

  • Always keep your fuel tank at least a quarter of the way full. Your fuel pump can heat up, or dry out and crack if there’s not enough gas on a consistent basis.
  • Gas acts as a coolant for the fuel pump, and if the tank runs dry then there is no liquid to cool the pump. Overheating shortens the life of the fuel pump.
  • The more gas you have in the tank, the easier it is for the fuel pump to work because of the increased weight putting pressure on the fuel pump. Without this pressure, the fuel pump has to work harder which can cause it to wear out faster.
  • Replace your fuel filter frequently. Impurities and any debris from gasoline or from dust and dirt that has gotten into the tank will sink to the bottom. When the fuel on the bottom of the tank is sucked into the fuel pump, the debris could cause damage. The fuel filter can protect the injectors and engine from debris but the pump is affected by the debris.
  • Make sure you have a good seal with the gas cap. If the gas cap is open, air and debris can get into your fuel tank, which can cause damage to your fuel pump.
  • Avoid gas pumps and gas stations that appear to be poorly maintained, or are otherwise rusty/dirty. If there is water in the gas or corrosion on the nozzles, this can cause damage to the fuel system and shorten the life of the fuel pump. Cheap gas is just fine, as fuel quality is well regulated in the US, but gas pumps in a state of disrepair are still present on occasion. As recently as 2012, there was an issue with BP gas stations in Indiana, Illinois and Wisconsin, BP with over 8 million gallons of gas being contaminated.

Signs Your Fuel Pump Is On The Way Out

Rust, dirt, or debris in the gas tank can kill a fuel pump very quickly. Rust occurs on older steel tanks while after 8-10 years, plastic tanks start to break down.

Diagnosing a dead fuel pump is usually fairly easy, which will save you on testing and diagnostic costs. What normally happens is the car has trouble starting and frequently will die. Finally, the car itself will refuse to start even though the engine is cranking itself and getting plenty of juice.

A great way to check if your fuel pump is bad is to check your fuse box. See if any of the fuses are blown. If the metal in each fuse is good, move on to the fuel pressure test port. 

You can get a pressure gauge for about $20-$30 bucks on the web.

Find your car’s fuel pressure test port and crank the engine. If it’s not getting any pressure, congratulations, you have a bad fuel pump.

Don’t you feel handy now?

Now, there are other signs to look out for prior to the car dying which may indicate you have a bad fuel pump. If you notice any of these, but your car is still running, we advise you to take your car to a mechanic before it decides to die on you.

1: Whining Noise From The Fuel Tank

Your fuel pump normally will hum quietly when driving under normal conditions. However, an aging fuel pump can make a racket. Of course, this can also be caused by fuel conditions such as not having enough fuel, or having bad fuel, but in most cases, this is one of the first signs your fuel pump is on the way out.

This can be caused by debris in the fuel pump. Unfortunately the fuel filter doesn’t filter out microscopic particles (particularly dirt and metal) that can cause damage to your fuel pump.

The only protection comes from the inlet screen. The inlet screen only blocks large particles and cannot block the microscopic particles that wear a pump out over time. When a pump gets worn, it may get louder and spin at lower an RPM causing starting, driveability, and performance problems. The first sign of this is a “wirrrrrrrr” noise that you can hear when turning on the car.

2: Trouble Starting

An aging fuel pump can have difficulty generating the required amount of pressure to start your car. It can still pump fuel, but it may require several cranks of the engine or multiple turns of the key. This symptom is far from definitive on it is own, as this could be a leaking fuel line or a bad starter. One way to tell is to use the pressure test described above.

3: Sputtering Engine

A sputtering engine can be caused by an improper mixture of fuel and air where your engine is likely running lean or rich. If you notice your engine sputtering at high speeds before returning to normal operation, your fuel pump may be to blame. Without the correct pressure, your engine may not be getting the fuel it needs. This is a dead giveaway that your fuel pump needs to be replaced.

4: Trouble Climbing Hills

When your engine is forced to work harder, it requires more fuel. A prime example of this is when climbing a steep hill. If you’ve got a bad fuel pump, your car can feel like it’s severely underpowered while climbing, even if you’re pressing the gas pedal. A weak fuel pump won’t be able to regulate and accurately provide the right amount of fuel to the engine in order to generate the correct amount of power.

5: Random Surges

An aging fuel pump may still work intermittently and send a surge of fuel into the engine which can feel like you’re pressing the gas pedal even though you’re going at a consistent speed. When the fuel pump is working properly, it should evenly deliver fuel to your engine.

6: Bad Gas Mileage

A bad fuel pump may be causing your engine to run with a rich fuel mixture, which can burn additional fuel. However, this is far from definitive, as this problem can be related to any number of things, including a bad O2 sensor, a cracked fuel line, or issues in the engine itself.

Facing A Fuel Pump Repair? You Don’t Have To Pay For It, If You Do This

While the fuel pump is covered with most extended warranty companies, Protect My Car is far from “any” extended warranty company.

Not only does it cover your fuel pump, but it also covers your engine, transmission, and other important parts of your car like your air conditioning, alternator, and so much more.

Replacing any of these bad boys would cost you thousands of dollars without a plan from Protect My Car.

As it stands, your fuel pump could cost you up to $1,011 dollars to fix based on our internal claims data. If you’re like us when you see that number and you wind up thinking something along the lines of “oh hell no, I’m not paying that”, then we’ve got some good news for you.

Starting at $2 a day, you can protect your vehicle and if your fuel pump is bad, Protect My Car will pick up the bill.

$2 a day or a $1,011 repair bill to fix your fuel pump?

It should be an easy choice.

Best of all, we’re able to do this at a lower price than our competitors because we’re a direct warranty provider.

As a proud direct warranty provider, you’ll never be mistreated when you join us. There’s a reason our average review score (Consumer Advocate, Consumer Affairs, BBB) is a 4.3/5.0, and I want you to find out why.

We know there are a number of other great extended warranty companies out there, we know we’re the best and we want to prove it to you.

That’s why, for a limited time, all new policies come with free oil changes and tire rotations. There’s no pressure. You can visit our online quote portal to see how affordable it can be to fix your fuel pump.

Don’t wait until your fuel pump breaks down and you’re stuck with the bill. Get covered today and make sure that you will never have to pay out of pocket for major vehicle repairs ever again.

About Protect My Car

Protect My Car is an extended auto warranty company. Our goal here at Protect My Car is to eliminate your worry of being financially responsible for an expensive mechanical breakdown. With our extended auto warranty, you don’t have to worry about being fully burdened with the cost of a covered repair.