How to Perform a Fuel Pump Replacement

Bad fuel pump symptoms like difficulty starting or engine misfiring often signal impending fuel pump failure. In such cases, you’ll need to replace the fuel pump to maintain fuel efficiency, delivery, and overall engine performance.

You can try to replace the old fuel pump yourself. However, we recommend hiring a professional mechanic as a fuel pump replacement involves dealing with gasoline (highly flammable).

Here’s how a professional mechanic would go about a fuel pump replacement:

1. Park the car on a level surface and set the parking brake.

2. They’ll locate the pump assembly in the fuel tank and have someone turn the key to the ON position — while the mechanic listens at the filler opening. The fuel pump should hum for 2-3 seconds. If it doesn’t, replacing the pump is essential.

3. Next, they’ll find and verify the vehicle’s fuel pump relay and fuse. If the fuse is damaged, replace it with a new fuse (same amperage). 

4. Once done, they’ll check the fuel pump’s operation. If the vehicle’s fuel pump works, the issue should be resolved. If it doesn’t and the fuse and fuel pump relay function perfectly, they’ll check for power and ground at the fuel pump. If there’s power and ground, the old pump is flawed.

5. They’ll relieve the fuel system pressure and disconnect the negative battery cable.

6. They’ll drain as much fuel as possible from the fuel tank. Disconnect the filler fuel hose and the electrical connection to the old pump.

7. Next, support the fuel tank using a jack stand and a block of wood. Remove the entire pump assembly, including the pump and the fuel level sending unit, and lower the tank.

8. Remove every hose clamp, disconnect the fuel line or fuel tank hose, and extract the original pump from the gas tank. 

9. They’ll compare the new fuel pump to the old fuel pump to verify if they have the correct part. Once verified, install the new fuel pump by connecting every fuel line.

10. Reinstall the straps and bolts. Reconnect the filler fuel and the electrical connector. Finally, reconnect the negative battery cable.

11. They’ll fill the gas tank and conduct a road test to verify the new pump replacement success.

Note: Get the clogged fuel filter changed when you get a new pump to avoid having the same problem again and needing more repairs.

What Are the Signs of a Bad Fuel Pump?

Here are some bad fuel pump indicators demanding a fuel pump replacement:

1. Weird Sounds

Whining from the fuel tank can indicate a fuel pump failure. Backfires and sputtering engines can also suggest a malfunctioning fuel pump.

In general, any pinging or knocking sound from your car is never good, so always pay attention.

Note: Any sound issues may trigger the Check Engine Light on the dashboard.

2. Diminished Engine Performance

There could be a loss of power if your car’s fuel pump can’t provide the engine with sufficient fuel. Also, high or low fuel pressure due to a faulty fuel pressure regulator may cause surging or sputtering. A less noticeable fuel pump problem can be a decrease in fuel efficiency.

In any of these cases, you may need a new fuel tank pump.

3. Difficulty Starting

If the fuel pump assembly can no longer supply the required fuel to the engine, your car will experience starting difficulties. Start-up may take a few seconds longer than usual, or you’ll need a few attempts to get the engine cranked. 

Ignore the issue, and eventually, your car simply won’t start. So don’t ignore a fuel pump replacement.

4. Misfiring 

Many things can cause misfiring, including a malfunctioning fuel pump. 

If the engine isn’t getting adequate fuel, it won’t have the proper air-fuel ratio in the combustion chamber — leading to inefficient combustion. This results in a misfire.

5. Unable to Maintain Speed

If the engine is choking or struggling to maintain speed, you may think you’re out of gas. Check the fuel pressure gauge. If the gauge shows fuel in the tank and the car’s choking, you have a failing fuel pump.

6. Overheating 

A faulty fuel pump can overheat. If you have an overheating fuel pump issue, the vehicle might run for 15-30 minutes before overheating and stalling. After letting your engine cool, it’ll run again, only to halt as the issue repeats.

7. Engine Surges

A failing fuel pump can send too much fuel to your engine. This will result in the engine surging, which means the vehicle picks up and then drops speed — making driving dangerous.

8. Low Fuel Pressure

Test your fuel pressure to spot the cause of a faulty fuel pump. 

Is the pressure low?
It could be due to a bad fuel pump or damage to the gasket sealer, hindering the pump’s ability to deliver sufficient fuel to the engine. You can buy a fuel pressure gauge to measure the pressure or let a mechanic help you.

Note: You can find the recommended fuel pressure in your owner’s manual.

How Much Does a Fuel Pump Replacement Cost?

A fuel pump replacement cost can be between $200-$600, including labor. However, this cost can go up further depending on the additional parts that need to be replaced. 

Here are the estimated costs for some parts:

• Fuel tank hose: $20-$40
• Fuel filter: $85-$100
• Fuel pressure regulator: $160-$195
• Fuel injector: $600-$1,200
• Fuel level sending unit: $1,100-$1,300

How Urgent Is a Fuel Pump Replacement?

Driving a car with a fuel pump problem can result in all of the bad fuel pump symptoms listed above, including your car running intermittently or not starting at all. That’s why you should get your car’s fuel pump replacement and maintenance scheduled ASAP.

3 FAQs About the Fuel Pump

1. What Is a Fuel Pump? 

A fuel pump is a critical part of your engine fuel line system. It moves fuel from your vehicle’s fuel tank to the carburetor or fuel injector in the engine through the fuel tank hose.

The fuel then combusts, helping you start the car and keep it running. 

2. What Are the Different Types of Fuel Pumps?

There are two kinds of fuel pumps depending on how they operate:

A. Mechanical fuel pump

Older vehicles with a carburetor will have a mechanical pump with plunger-type or diaphragm pumps. You’ll typically find this kind of pump mounted on the engine block with the engine’s camshaft working the pump.

A mechanical pump uses a pulling force to move gasoline through the different car components. The fuel is controlled with an inlet valve. It closes when fuel in the carburetor’s float bowl is filled and opens when more fuel is required. 

A mechanical fuel pump may be more convenient, less costly, and easier to access than other pumps.

B. Electric fuel pump

You’ll find an electric pump in most modern vehicles with a fuel injection system. This fuel pump doesn’t have a diaphragm or plunger to pull gasoline. Instead, it uses an electric motor to push gasoline through the different components and a fuel pressure regulator to regulate fuel.

An electric pump can be mounted inside the fuel tank on a bracket. You can access the pump from an access port on top of the tank. An electric pump is designed to let it stay submerged in gasoline. 

An external electric fuel pump also exists. It sits outside the fuel tank.

3. How to Make the Fuel Pump Last Longer?

Here’s how to avoid fuel pump failure and make your pump last longer:

• Avoid regularly driving with low gas in your gas tank to reduce fuel pump stress. 
• Ensure your gasoline is free of impurities.
• Prevent accumulation of dirt and debris in your gas tank opening or around the fuel pump assembly. This can lead to fuel filter blockage.

Note: A fuel pump can still clog and experience wear and tear over time. It’ll start showing signs of damage after 7-8 years or 100,000 miles.