Do Fuel Pumps Go Bad From Sitting? (2022)

A fuel pump plays an essential part in the operation of a vehicle. It takes the fuel from the fuel tank and relays it to the engine so the car can start and run. However, can a fuel pump go bad if your vehicle has been sitting too long? We have the answer to that question in this article!

If your vehicle is sitting too long, then the fuel pump can go bad. This can happen because the pressure has gotten too low, which means the vehicle cannot start. Modern-day fuel injections systems need high pressure to function correctly, and when a car sits too long, the fuel pump won't deliver that level of pressure.

If your car has been sitting for a while, there are several reasons why it won't start. However, a fuel pump going bad after a car has been sitting is a common culprit. In this article, we will discuss the signs of a fuel pump going bad. In addition, we will discuss how long a fuel pump will last and the costs of replacing one, so keep reading!

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Do Fuel Pumps Go Bad From Sitting? (1)

Do Fuel Pumps Go Bad From Sitting?

Fuel pumps do not go bad immediately after a vehicle has been sitting. Instead, the fuel pump usually goes bad over time because it becomes less effective at taking fuel from the tank and sending it to the engine so it can run.

When your car sits for too long, the gas inside of the fuel tank starts to break down. As that happens, the pump becomes less effective at moving gas into the engine. When that happens, the car will not start because it doesn't have enough fuel pressure to get going.

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In addition, fuel pumps will usually go bad from sitting overnight. If you have a vehicle that you don't drive daily, then it is very common for the fuel pump to die after a car has been sitting overnight.

Do Fuel Pumps Go Bad From Sitting? (2)

This is because of how cold the temperature gets overnight and how cold the gas becomes inside the tank. The cold temperature causes the fuel pump to work harder and faster, leading to burning out and dying.

In addition, a fuel pump will go bad from sitting overnight because of condensation. When a car sits for too long, especially during cold nights, there is a good chance there will be some condensation inside the tank.

Since gas and water don't mix well together, when you start your car in the morning, the gas will mix with the condensation in the tank, which can lead to running issues.

What are the signs of a fuel pump going bad?

There are several signs of a fuel pump going bad, but there are main signs you should keep an eye out for if your car has been sitting too long.

Delay in Acceleration

You have to press the gas pedal down further than usual to get the car moving. This is one of the most common signs that something is wrong with the fuel pump. This is usually a sign that the fuel pump is going bad and should be replaced as soon as possible.

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Trouble Starting

The fuel pump may be going bad if the car has trouble starting, especially after sitting overnight. For example, if your car doesn't start immediately after turning the ignition, the fuel pump might have a problem.

Check Engine Light Comes On

The check engine light is on after the car has been sitting overnight. - If your car doesn't start when you turn the ignition in the morning, but you have recently had maintenance or repairs done to it, then there might be a problem with the fuel pump. When this happens, the check engine light might come on because of a fault that has been stored in your car's computer.

Slow Acceleration When Speeding Up

If the car is slow to accelerate or lacks power when you speed up, then this is another sign that something is wrong with the fuel pump. To maximize the life of a fuel pump, it's always a good idea to have regular tune-ups done to your vehicle. Not only do regular tune-ups prolong the life of the car, but they will also prevent problems before they happen.

Fuel Tank Noise or Vibrating

After driving your car for an extended period, you might hear the fuel tank vibrating or making noise under the car. - If you hear loud noises coming from under your car when you are driving around, then it is possible that something is wrong with the fuel pump. I

Power Loss

If your car is losing power when driving it, this can be another sign of having a bad fuel pump. When the car doesn't have enough power to drive around, then the chances are that the fuel pump has stopped working.

Low Fuel Efficiency

If your car is losing fuel efficiency when you drive it, it can be a sign of having a bad fuel pump. When the car is losing fuel efficiency, something might be wrong with how the car uses gas.

How long should a fuel pump last?

A fuel pump can last on average about 100,000 miles. However, as discussed above, a fuel pump can go out sooner if the vehicle has been sitting for an extended period of time.

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In addition, the fuel can go bad if it has been sitting in frigid cold weather conditions for a short period of time. This is because the fuel pump has to work harder and faster when starting a car up in cold weather.

Can I drive with a bad fuel pump?

When it comes to driving with a bad fuel pump, you should not drive the car around. When the car has a bad fuel pump, it will lose power and stall at intersections or on the road. This is why it is best to have your fuel pump replaced as soon as possible so that you can minimize any risks of accidents when driving.

How expensive is it to replace a fuel pump?

Getting your fuel pump replaced is not cheap. However, the price depends on what type of car you drive and if other parts need to be replaced. The costs can range from $220 to as much as $1,000. Typically, the fuel pump can be about a two to three-hour job to be replaced.

The price of getting a fuel pump can also vary depending on the mechanic shop. It never hurts to shop around and get different price quotes.

Can you fix a fuel pump without replacing it?

It is possible to fix the fuel pump without having to replace it. However, this can be a long and arduous process that requires you to take apart your car's entire fuel line system.

For example, if your fuel filter has gone wrong or dirt is clogging up something in the fuel line system, you will need to fix this before repairing the fuel pump.

However, if you are not good at doing car repairs or do not have the time to take apart your entire car's fuel line system, then it might be best to bring your vehicle to a mechanic who will be able to correctly diagnose the problem with your fuel pump and fix it for you.

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If you want to replace the fuel pump on your own, this is not recommended. You can buy a fuel pump and install it by yourself, but you might end up making the problem worse. Also, if you are not sure what is wrong with the fuel pump in your car, then it's better to bring in a professional who knows what they are doing.

Car won't start when replacing the fuel pump—What to do?

If you replaced the fuel pump and your car still won't start, there could be issues within the fuel lines.

When you removed the fuel lines, it is possible that they didn't go back on correctly, or they were loose. A loose connection could cause a loss of pressure, and therefore your car won't start up again.

It's also possible that there are micro leaks within the connections where the fuel line meets the pump. When this happens, you will need to go to a mechanic and have them look at it.

Do Fuel Pumps Go Bad From Sitting? (3)

Final Thoughts

The fuel pump is one of your car's most essential parts. This is because the fuel pump is what keeps your engine running smoothly and without any problems with the gas that goes into the vehicle. For this reason, it is important to get your car checked if you notice that there are issues with your vehicle starting up or if there is any hesitation or lack of power while driving.

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What causes fuel pumps to go bad? ›

The top reasons for fuel pump failure are contamination, overheating, and the gears in the the fuel pump wearing out over time. Rust, debris, and dirt are three common particles that can somehow enter the gas tank and be fed towards or through the intank fuel filter and possibly into the fuel pump.

What happens to fuel when it sits? ›

Old gasoline is one of the more obvious concerns with letting your car sit for too long. Gas usually lasts for at least a month without any issues, but over time it can oxidize and leave carbon deposits in your fuel system. This can have serious implications for your engine's fuel efficiency, performance and health.

How long do fuel pumps last? ›

The fuel pump is your vehicle's unsung hero. It takes gas from the gas tank and sends it to the engine so your car, truck, or SUV can start and run. Your vehicle's fuel pump should last at least 100,000 miles or more.

Do fuel pumps get weak? ›

Because fuel pumps constantly run whenever the ignition is turned on, they can eventually wear out and weaken over time. A weak fuel pump may still pump fuel, but the vehicle may experience difficulty starting from the lack of pressure.

Do fuel pumps go bad all of a sudden? ›

Fuel pump failures tend to be sudden and unpredictable, with few symptoms to warn the motorist that trouble is brewing. And the higher the mileage on the vehicle, the greater the risk of a fuel pump failure.

Can a fuel pump fail without warning? ›

If you ignore all of the other warning signs of a failing fuel pump, it will eventually fail completely. Once your fuel pump has finally given up the ghost, no fuel will reach your engine. You may hear your spark plugs firing when you try to start your car, but without fuel, the engine won't be able to turn over.

What happens to a car that sits for 3 months? ›

But when your vehicle is sitting, your car's battery will likely go dead in just two or three months. Why? Because when you drive your car, the vehicle's alternator continually recharges the battery to replenish the power you're using. No driving means no charging — and a dead battery.

Do Cars Lose gas sitting? ›

Wastes gas. Leaving your engine running consumes gasoline. As a matter of fact, allowing your car to idle for two minutes is equivalent of driving a mile. You can waste almost a gallon of gas if you leave your car idling for more than an hour.

Will a car start with 5 year old gas? ›

However, gas that is more than two month old is generally OK to use with only minor decreases in performance. Gas that is older than a year can cause issues, like engine knocking, sputtering and clogged injectors. Bad gas can be drained from the tank to prevent damage to the engine.

How can you tell if a fuel pump is bad? ›

Warning Signs of a Bad Fuel Pump
  1. The car won't start. If the vehicle is struggling to start or isn't starting at all, your fuel pump may be damaged or clogged. ...
  2. The car sputters or dies while driving. ...
  3. The engine surges while driving. ...
  4. You hear whining in the backseat. ...
  5. You notice lower gas mileage.
29 Apr 2022

Why does the gas pump keep stopping when my tank isn't full? ›

There is a reason gas pumps have an annoying habit of shutting off. Gas pump nozzles are designed with a device on the end that turn off the fuel flow when the gasoline runs back into it. This is a safety mechanism which prevents the gas from coming out and spilling when filling up the tank.

Does a bad fuel pump throw a code? ›

Bad Fuel Pump, Fuel Pressure Sensor Can Trigger 'Check Engine' Light, P0087 Code. Your car's “Check Engine” or “Service Engine Soon” light can flash on for more than 1,400 different reasons.

Can a fuel pump work sometimes? ›

If your vehicle has a mechanical fuel pump, it's unlikely that the fuel pump has failed. This is because mechanical pumps tend to fail entirely…if you have a mechanical fuel pump with a problem, your engine isn't getting any fuel at all. There's no such thing as an intermittent mechanical fuel pump failure.

How long is too long for a car to sit without being driven? ›

If you're not looking to store your vehicle indefinitely, which involves different procedures and prep work, experts recommend vehicles be driven every two to three weeks.

How long is too long for a car to sit? ›

So how long can you go without driving your car? If you have not prepped your vehicle for a long time of not driving it you should not let it sit for more than one month, and even then, you should try to start it up and drive it for 15-30 minutes a few times within the month.

How long can a car sit before it has problems? ›

Typically, your car can sit about four weeks to two months without driving before the battery dies. The reason your car can sit only for so long before it dies is the fact that your car battery is in use even when you're not behind the wheel.

Can I mix old gas with new gas? ›

Old and new gas should not be mixed for a variety of reasons, the major ones are; The old gas degrades over time it should not be added because it has already lost it's combustibility. It can cause sputtering. It might fail to fire it up.

Is it better to keep gas tank full? ›

Help avoid an emergency. Having a full tank of gas prevents you from being stranded or getting stuck in an accident or traffic jam without a means to keep your vehicle running. You can also avoid having to call a tow truck or roadside assistance.

Is it bad to sit in your car while its running? ›

Sitting in an idling car means you are breathing in more of the dirty exhaust that leaks into the car cabin. Any warmth you may get from a car heater is not worth the damage to your health. If parked and waiting, it is healthier to get out of your car and go inside a store or building.

Will seafoam help old gas? ›

Sea Foam Motor Treatment won't “restore” old fuel, but it will clean gum and varnish that formed as a result of the old fuel. It's a great way to clean a fuel system that has been sitting a while with old fuel in it.

What year do gas cars become illegal? ›

In summary

California will ban sales of new gas-powered cars by 2035, but the conversion to battery-powered vehicles poses numerous unresolved issues.

Can a fuel pump go bad from sitting? ›

If your vehicle is sitting too long, then the fuel pump can go bad. This can happen because the pressure has gotten too low, which means the vehicle cannot start.

How often should I change my fuel pump? ›

Fuel pumps are meant to last around 100,000 miles, but most people never have to replace their fuel pumps. They are typically built to last since they are positioned in a hard-to-access place within your fuel tank.

How can I test my fuel pump without a tool? ›

Disconnect the hose coming from the pump to the filter and block the passage of the hose tightly with your finger. You can then start the car. If you feel that the fuel is pushing your finger hard, it means you have good pressure. If not, then you require replacing the pump.

How do you check a fuel pump without a pressure gauge? ›

The simplest way is to just listen for the hum of the fuel pump when you first turn your car on. You can also use an OBD II scanner. Testing your fuel pressure without a gauge is always going to be a bit imprecise and you should get a gauge as soon as it's convenient.

Can AutoZone test my fuel pump? ›

AutoZone makes checking fuel pressure easier than ever. Get a fuel pressure test kit and check the fuel pump and fuel system on your ride today. If you've ever wondered how to test a fuel pump, you may have assumed it was a pretty complicated job.

How do you remove air from a gas tank? ›

But, taking it at full-face value, “removing air from a gas tank” simply means filling the 'air' space with something else. So the answer is obvious to me - fill it with gasoline. The liquid gasoline will displace the air that is in it.

What mimics a bad fuel pump? ›

Related component failures like stuck fuel pressure regulators can reduce fuel pressure and thus mimic a worn fuel pump.

Can a scanner detect a bad fuel pump? ›

This part of the fuel system is called the high-pressure side. Factory and enhanced scan tools can monitor pressure transducers on the high and low sides of the system. This information can be used to diagnose the health of the low-side and high-side pumps.

How do you stop a fuel pump from failing? ›

Two ways to reduce or eliminate fuel pump failures:

Never let your fuel level get below 1/8th to 1/4th of a tank. Change your fuel filter at 30,000 mile intervals (most vehicles)

How do you fix a fuel pump without replacing it? ›

How to fix a fuel pump without replacing it?
  1. Use Fuel Pressure Gauge. This can be one of the best alternative solutions when you are concerned with the various ways to deal with a bad fuel pump to start your car. ...
  2. Applying Some External Pressure. ...
  3. Maintaining The Engine's Heat.

How often do fuel pumps fail? ›

Your car, truck, or SUV's fuel pump will last over 100,000 miles on average. Most people never have to have their fuel pumps changed. You can tell if your pump has problems, however.

What kills a fuel pump? ›

The most common cause of fuel pump failure is frequently running the tank low on fuel, which causes the motor to overheat. The second most common cause is fuel contamination, usually dirt and rust particles that clog the fuel strainer and prevent the pump from drawing enough fuel under high engine load.

How do you start a car with a bad fuel pump? ›

If your car's fuel pump has gone bad—but hasn't completely stopped working—you should still be able to start it by applying manual pressure, attaching a fuel pressure gauge, or making sure the engine receives consistent heat.

Can you drive with a broken fuel pump? ›

Yes, there are some methods that allow you to start your vehicle when it has a bad fuel pump, however, keep in mind, these are only for a temporary time. When the fuel pump is failing or has failed, you need to get your car to your mechanic post-haste.

Can you start a car without a fuel pump? ›

Your engine won't start at all – Simply put, if the pump has indeed failed, you will not be able to drive your car. Without fuel, the motor won't be able to run. An engine can also fail to start for various other reasons, including a dead battery, alternator, starter, or even a clogged fuel filter.


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