fuel pump

Fuel Pump Symptoms, Function & Replacement Cost

In Engine by Magnus Sellén1 Comment

fuel pump

The fuel pump is an important component in your vehicle, and it is usually essential for the functioning of an internal combustion engine system.

In all modern vehicles, a fuel pump is a necessary component, whereas in older vehicles the function depends solely on gravity to deliver the fuel.

A fuel pump can improve the efficiency of fuel delivery by providing just the right amount of fuel to maintain the correct air-fuel mixture in the combustion engine.

A fuel pump can be damaged or fail for a variety of reasons, such as the consistent use of contaminated fuel or the use of poor quality fuel. In this article, you will learn the most common symptoms of a poor fuel pump.

Signs of a Bad Fuel pump

In this special article we will highlight the many symptoms that are likely to indicate fuel pump failure. First you will find a table with the most common symptoms, causes and solutions; further down you will find more information about them.

1. Car Experiences Hiccups

Cars need fuel to drive, just as we humans need food. It is easy to understand how important fuel is, and it is also easy to see that your car will not meet your expectations if the correct fuel supply is not guaranteed. If you press the accelerator and feel that your car has hiccups, you may have problems with the fuel pump.

The fuel pump may be choking due to inferior fuel, or the fuel pump may not be generating enough pressure to push the fuel forward into the system.

2. Ignition Related Difficulties

An insufficient supply of fuel to the combustion chamber will not create enough excitement in the chamber to cause an explosion. No combustion means that the engine will not start at all. Even if it does, you will find that it takes you a long time to reach ignition.

3. Abrupt Engine Shutdown

This is another problem that could be caused by improper fuel supply to the engine. The engine could suddenly shut down during operation and not start at all. If this occurs regularly, it is time to arrange a meeting with your local mechanic.

4. Engine Timing

This is not a symptom you will see immediately, but if you cannot identify the failing fuel pump by other symptoms, this symptom will probably add itself to the list. Your engine will regularly misfire and backfire, which confirms your doubts about the fuel pump failure.

5. Check Engine Light Illuminates

Fortunately, modern cars are loaded with sensors that can detect any number of problems as soon as they occur. One of these sensors is a fuel pressure sensor that is intelligently placed near the fuel pump. If an irregularity is detected, the sensor sends a signal to the ECU, which lights up the check engine light.

You can easily check the error code displayed by the Check Engine Light through an OBD2 Scannerir?t=askamastermec 20&l=am2&o=1&a=B01MR7FZS1.

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6. Thick Black Smoke from Exhaust

Vehicles do not normally emit black smoke from their exhaust, unless they are powered by diesel fuel. If your gasoline-powered car emits such smoke, there is usually engine damage. One of the causes of black smoke is a defective fuel pump.

7. Turbocharger Underperforms

First of all, not all cars have a turbocharger, but those that do have one have a bonus symptom. Turbochargers work by heating air to rotate a turbine that delivers additional power to the engine. Turbos need time to spool air; this time is usually called turbo lag. So if you feel that there is a lot of turbo lag, there could be a problem with your fuel pump.

8. Spark Plugs Will Die Sooner

A defective fuel pump interferes with the internal workings of the engine. The greatest damage occurs in the cylinder itself, and the smallest components take the greatest damage. This means the spark plugs will die before their time. So if you feel that your spark plugs need to be replaced too soon, you’re dealing with a faulty fuel pump.

ProblemSymptomsCausesSolutions
Bad Fuel pump (Pressure)Rough Acceleration

Hard starting condition

Check Engine Light illuminates

Rough Idle
Faulty Fuel Pump

Faulty Fuel pump wirings

Faulty Fuel pump relay
Replace Fuel pump

Repair faulty pump wirings

Replace fuel pump relay

fuel pump insidfeWhat is a Fuel Pump?

The main function of the fuel pump is to deliver and inject fuel into the system of the combustion engine. In most cases, carburetor engines use the function of mechanical fuel pumps, which are mounted outside the fuel tank and operate under low-pressure conditions.

Apart from carburetor engines, fuel-injected engines use two main pumps to deliver fuel, which work electrically and improve performance efficiency.

One pump is installed inside the fuel tank, which delivers more fuel at low pressure, while another pump is installed near or inside the engine, which sucks in the required amount of fuel at a higher pressure.

For the maximum efficiency and proper functioning, the fuel pump operates under certain conditions that are electronically adjusted to precisely optimize the air-fuel mixture in the combustion engine. If more fuel is supplied to the engine, the air-fuel ratio is disturbed and all the fuel cannot burn efficiently.

As a result, the fuel is highly utilized and wasted, while the engine’s performance is also affected. On the other hand, insufficient fuel supply to the engine can cause stalling, misfiring, and lean running. To optimize the correct fuel supply, the fuel pump uses electronic data to supply the correct amount of fuel to the engine.

Solutions of a Faulty Fuel Pump

Fortunately for you, the fuel pump problem is not a big problem, but one you can solve yourself. However, we would advise you to consult a professional mechanic for such work.

Replace the Screen Filter

If you are sure that your car has a bad fuel pump, the first thing you should do is check the screen filter. The screen filter, as its name suggests, protects the fuel pump from dirt and dust. It can, therefore, become clogged in no time at all. So if you want to have free-flowing fuel through your engine, replace the screen filter.

Check Voltage

The fuel pump works by means of electricity. So if there is irregular voltage transmission through the car, your fuel pump will be one of the first components to be affected. Therefore, after diagnosing the failure of the fuel pump, check your car’s battery and the wiring that supplies power to the battery. There will probably be a fluctuation in the voltage from the battery.

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Change the Fuel Pressure Regulator

The fuel leaves the chamber of the fuel pump through a small opening. This opening is controlled by a regulator. If the regulator goes wrong, your fuel delivery will be affected and in the long run with a higher or lower resistance, the fuel pump will be damaged.

Replace the Fuel Filter

Let’s face it, the fuel we receive is not always of the highest quality, which means that deposits can get into your fuel tank even after a rigorous testing procedure. The only thing that protects your fuel pump from being exposed to harmful deposits is the fuel filter.

If the fuel filter is clogged, your car’s fuel pump will have difficulty getting fuel to the fuel track and will make the pump work more than necessary.

inline fuel pumpWhere is the Fuel Pump Located?

The location of your fuel pump may vary depending on the type of vehicle and manufacturing process. For most vehicles, especially cars, the fuel pump is usually located under the rear seat of the vehicle.

Since the location may vary for some vehicles, it is recommended that you refer to the service manual provided by the manufacturer, which contains the exact location information. You can find the fuel pump in the tank by lifting the panel behind the rear seats. It is normally located on top of the fuel tank.

Fuel Pump Replacement Cost

The average replacement cost for the fuel pump is between $540 and $880. Parts cost between $460 and $600, while labor costs range from $80 to $290.

Most of the time, if your vehicle’s fuel pump is defective, the best option is to replace the part. In less severe cases, the problem can be fixed by cleaning and washing, but it is recommended that it be replaced.

The fuel pump is an essential part of your vehicle and the cost of replacing the fuel pump is comparatively high compared to many smaller parts. If you buy a brand new fuel pump, the cost of a new pump for most vehicles can range from $460 to as much as $600 for the part alone.

In addition, you will have to pay extra labor costs if you hire a mechanic to replace the fuel pump. The mechanic can charge you between $80 and $290 depending on the type of vehicle, the time it takes to replace the part, and the mechanic you are dealing with.

Therefore, the total cost of what we’re talking about here averages between $540 and $880 for both the parts and labor costs. For luxury cars or special vehicle types, the price may be higher.

How to Replace the Fuel Pump?

Replacing a fuel pump is a relatively simple task. Usually, the replacement can take up to an hour to two hours if you try to do it yourself, depending on your expertise and practice. Here is a brief step-by-step guide on how to easily replace your fuel pump.

  1. Locate the fuel pump by referring to the service manual of your car.
  2. Remove the cable attached to the negative terminal of the battery.
  3. Carefully check the fuel line all along to see if it is damaged.
  4. Replace the fuel line in case it is damaged or cracked.
  5. Follow the service manual of your car to carefully release the pressure from the gas tank.
  6. Remove the ties and clamps that are holding the hoses and remove the hoses from the pump.
  7. Block the hose with a bolt or an object.
  8. Remove the fuel outlet by removing the screw.
  9. Remove the bolts from the fuel pump and pull the fuel pump out.
  10. Match the new fuel pump with the old one.
  11. Clean the mounting area of the fuel pump properly.
  12. Apply the sealer on both sides to coat it.
  13. Place the new pump and fasten the bolts on it.
  14. Reconnect the fuel outlet and fasten the removed bolts.
  15. Reconnect the hoses to the new pump and the fuel line.
  16. Reconnect the cable that was removed from the negative terminal of the battery.
  17. Turn on the engine and test the new pump to make sure there are no leaks.
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How to Diagnose a Bad Fuel Pump?

Here you will find step-by-step instructions on how to diagnose a defective fuel pump in your vehicle.

  1. Do an electrical test.
  2. Check for the fuel pump fuse to see if it is in order.
  3. Test for the voltage at the pump itself.
  4. Do a drop test with the help of a voltmeter. You should get less than 1 volt of difference if the pump is good.
  5. Do a fuel pressure test.
  6. Remove the filter to see if the pressure is restored. The problem can be due to filter clogging.
  7. Do a pressure test with the help of a pressure gauge.
  8. Ask someone to rev the engine to check the pressure on the pressure gauge.
  9. Match the pressure readings with the service manual provided.
  10. The pressure should also increase with the revving if the fuel pump is in good condition.

Repairing or Replacing the Fuel Pump

The fuel pump can be replaced very easily in most cars. In some cars, you have to remove the fuel tank to get to the pump, and this can be quite difficult. However, remember that finding a fuel pump that is compatible with your car can be a painful and torturous task, especially if it is an old car model.

Assuming you are lucky and find one, the next step is to negotiate the price with the mechanic, as replacing the fuel pump can cost a lot of money.

Remember that the mechanic will charge you the price after looking at the make and model of your car. So make an accurate estimate before you think about a replacement. To get a general idea, we would say that you should expect to spend between $300 and $950, not including labor costs. These prices will, of course, depend on the make and model of your car and the availability of the part.

Hello I'm Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I'm specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I'm here to give you answers to all your automotive questions and I hope that you enjoy our content.

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  1. Your Comment * please i have a fuel pump problem in my vehicle, i change fuel pump almost every month, please help me, what would I do to solve this problem ? Thank you

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