9 Symptoms of a Bad Fuel Pump

Bad fuel pump symptoms are easily noticeable if you pay attention. Your vehicle might warn you with various symptoms, some a bit mild while others involving the shutdown of your vehicle. 

Here are some of the symptoms you’re most likely going to experience: 

1. Fuel tank making a whining noise 
2. Inability to start the car 
3. Rise in temperature then stalling  
4. Car jerks or sputters
5. Loss of power when accelerating 
6. Engine surges 
7. Loss of power when towing or driving uphill 
8. Fuel pressure gauge malfunction
9. Sudden decrease in gas mileage 

Now I will explain each of these symptoms in-depth so you, my friend, understand when you have a bad fuel pump.

1. Fuel tank making a whining noise 

This is usually the first symptom you’ll take note of, and it can be annoying. When your car is running and your fuel pump is worn or old, it will start making a howl or loud whine. It’s normal for fuel pumps to produce a quiet hum when it is in operation, but it is a bad fuel pump symptom when it gets too loud. 

2. Inability to start the car 

This is a serious bad fuel pump symptom because it’s signaling that the pump has failed, and it is at a point where it cannot provide the needed fuel for your engine to start running. 

If this is the case, you’ll still be able to crank your engine when you turn the key, but it won’t start due to the lack of fuel. 

However, there is the possibility it’s not the fuel pump that is making your car unable to start. There is are many reasons that could cause this, so you’ll have to proto diagnose your vehicle at an auto repair shop pro properly rise temperature then stalling.  

This is another important indicator of an issue with the fuel pump. If your car’s temperature gauge is displaying an increasing temperature and then the vehicle is stalling as well, you’ll need to get the fuel pump diagnosed and repaired as quickly as you can. 

However, there is the possibility that this increase in your car temperature might be due to several other reasons, and not the fuel pump. Nevertheless, whatever the reason might be, it’s usually a significant one. So you’ll still need to take your car to an auto repair shop. 

4. Car jerks or sputters

If you’re on the freeway and speeding, then the engine sputter or jerks; that might be a symptom of a bad fuel pump. The sputtering or jerking occurs because the fuel needed to make your vehicle function smoothly could not be delivered to the engine, so it’s only receiving air instead of receiving fuel. 

When fuel isn’t flowing to the engine, this makes the engine skip numerous power strokes required for its function, so it ends up jerking or sputtering. When it is still in its early stages, it might sputter for just a minute before the engine resumes its operation. This might make you confuse it with the effects of dirty gas. However, with modern fuel standards, the likelihood of a fuel pump failure is higher, so act fast if you experience this. 

5. Loss of power when accelerating 

If your car often loses power when you put your foot on the accelerator, that might signify that the fuel pump is faulty. To accelerate, you need fuel, and the gas pedal forces the fuel pump to pump harder. If the fuel pump is unable to pump harder, it won’t keep up with the increase in demand to meet your increasing speed because it will starve your fuel engine. 

If your car signs stalling when you try to accelerate after a stop, you might need to get it inspected. 

6. Engine surges 

When your fuel pump starts wearing, its components don’t wear out at the same rate, some wear faster than others, thereby making a particular area very functional while the other areas will be in a terrible state. The latter areas will make the pressure in your fuel lines inconsistent. If this is the issue, you might notice your car accelerating for a few moments without you pressing the gas pedal (this is known as surging). 

7. Loss of power when towing or driving uphill 

When you’re towing a load with your vehicle or driving up a hill, it will put extra strain on the engine, making it demand more fuel for optimal performance. If your fuel pump is faulty, it won’t be able to supply the increased fuel demand, and it will put a strain on the pump, causing it to fail. 

With your weak pump, maintaining a steady flow of fuel won’t be possible, so there will be a loss of power. This is a bad fuel pump symptom and you should have it fixed as soon as you can. 

8. Fuel pressure gauge malfunction

The amount of fuel supplied to the engine is indicated in the pressure gauge. Different brands and models of cars have a specific amount of fuel that needs to reach the engine to function well. If the specified amount of fuel doesn’t reach the engine, you’ll start experiencing some issues, leading to engine failure. 

To solve this issue, you need to check your vehicle’s owner manual to see the amount of fuel needed for the engine. After getting the specified amount, you’ll have someone revive the engine then you’ll focus on the pressure gauge. If the gauge shows less fuel than is needed, then you have a bad fuel pump. 

You’ll have to get your pump fixed as soon as you can. 

9. Sudden decrease in gas mileage 

Fuel pumps have a relief valve that controls the amount of fuel that goes to your engine. If the relief valve does not open on time, excess fuel will go to your engine. You’ll start experiencing low mileage issues, and your fuel tank will need to be refilled often. 

Types of Fuel Pump

bad fuel pump symptoms (1)Over the years, vehicles have moved from mechanical pumps to electric pumps. With these improvements in fuel pumps, there has been more functionality. We will show you the different types of pumps available and how they function. 

• Mechanical fuel pump

This fuel pump type makes use of positive displacement with a diaphragm or a plunge. The pump will suck in fuel, then trap it. The fuel is moved toward the engine and carb. It repeats this process of sucking in fuel and trapping it then moving it so that the car will function smoothly. 

• Rotary vane

This is just like a mechanical pump because it uses positive displacement to move the fuel. Inside this type of pump, there is a rotor with paddles. The rotor operates off-center, and since it’s off-center, it can create a pocket of space that lets fuel in. 

As the rotor moves, the vanes will close so it can trap a small amount of fuel, then it will release the fuel once it passes the outlet valve. There are different types of rotary vane pumps — sliding vane, rolling vane, swinging vane, and flexible vane. 

• Gerotor 

This type of pump also uses positive displacements like the mechanical pump and rotary vane, but there are numerous parts designed on it that it uses to function. This pump has two interlocking gears. These Two interlocking gears help trap a small amount of fuel; they will be pressurized and released afterward. 

• In-tank and Inline 

These two have an opposing designs, but they are both innovative 

Most of the vehicles produced nowadays have their fuel pumps situated inside the fuel tank, and this type of fuel tank is known as an in-tank. Being inside the fuel tank protects the fuel pump modules, and the gas in the tank will keep it cool. It’s a great and innovative fuel pump design. 

This Inline fuel pump is a much easier fuel pump to replace when compared to the in-tank pump because it isn’t located inside the fuel tank. This pump is situated in the middle of the engine and the gas tank, installed via the fuel system track. This fuel pump is often mounted in the engine bay or under the car. The inline pump structure is different from that of the in-tank. 

• Electric fuel pump: 

This type of pump has an electronic fuel injection system, as the name implies. It is found in modern cars that require higher pressure, and electronic pumps make this pressure achievable, unlike the mechanical module. 

How to Start a Car With a Bad Fuel Pump

There are about four to five methods you can use to start a car with a bad fuel pump. Some work best for traditional fuel pumps, while others work only with electronic fuel pumps. 

1. Apply pressure manually

If your fuel pump stops working, it won’t provide enough pressure required to pump the fuel necessary to power your vehicle so the engine will work. You’ll have to provide this pressure manually so fuel can flow to the engine. To apply the pressure, you will need to get an air mattress pump. It is one of those solutions that have proven to work countless times. 

2. Fuel Pressure Gauge

Using a fuel pressured gauge to start a car that has a bad fuel pump is a highly effective method. It’s this same method that mechanics use when diagnosing a bad fuel pump. Apart from being reliable, it is actually easy to go about. 

Fuel pressure gauges are handy diagnostic tools. They will help you monitor the engine pressure levels to prevent the fuel pump and the fuel injectors from getting damaged. Moreover, it’s actually cheap to get a fuel pressure gauge. 

All you’ll do is attach the fuel pressure gauge to the engine.

3. Regulate engine heat 

To keep the engine running, you must prevent it from overheating, especially when you have a bad fuel pump. However, you can only use this method if your car has started running. To prevent the overheating of the engine, you must not run it for long periods. When the engine cools down, the fuel pump will reset, which will stabilize your car’s performance. 

4. Troubleshooting 

You can only troubleshoot electronic pumps. Nevertheless, it is still a tricky thing to do. It’s usually a wiring problem or a fuse that makes the electric pump fail (this applies to only electric vehicles). The issue will make it almost impossible for power to get to the fuel pump needed to make your vehicle work efficiently. If this happens, whatever fuel is left in the fuel line, the engine will use it, and when it needs more and can’t get it, the engine will stall. 

If you’re using a very modern car, the fuel delivery system of your vehicle will be controlled by the engine control module. So if the reason the fuel pump failed is because of a problem within the wiring or circuit, the ECM is what you’ll reset. 

If the issue isn’t solved after resetting the ECM, you’ll have to replace the relay fuse of the fuel pump. After replacing it, your vehicle should get started. 

Can You Drive a Car With a Bad Fuel Pump?

We believe you now know how to start a car with a bad fuel pump. Unfortunately, this doesn’t guarantee you’ll be able to drive the car around. After starting it, you’ll have to take it to the nearest auto repair shop to get it serviced. 

If you could start the car with the bad fuel pump, just know that it is a temporary solution. You can’t drive your vehicle to a long distance, and in some cases, it might shut down back after driving it for just a few minutes. You can only enjoy your vehicle to the fullest after you have replaced the fuel pump. 

Conclusion

Once one of the bad fuel pump symptoms appears, you shouldn’t postpone the repair of the fuel pump because the following symptom might not be as mild as before, and you could be on the highway when it occurs. Visit your mechanic or auto repair shop as soon as you can. Solving this issue won’t require you to break the bank.