So you think your fuel pump might be bad? Some of the symptoms of a bad fuel pump can also be caused by different problems with your car… so your fuel pump might not even be the problem! This article explains the most common bad fuel pump symptoms and will help you determine if your fuel pump is the actual source of the problem with your car.
Fuel Pump 101
Knowing a bit about a fuel pump will help you understand the bad fuel pump symptoms explained in this article. So here’s a quick and simple overview.
As you’ve probably guessed, a fuel pump is a pump that pumps fuel (duh).
In most newer cars, the fuel pump is located inside of the fuel tank and is submerged in gasoline.
It pumps fuel from the fuel tank to your engine where said fuel is mixed with air. The mixture is then ignited by spark plugs. These tiny little explosions (AKA internal combustion) are what makes your car go vroom-vroom.
So without a working fuel pump, you’re not going anywhere!
Now that you have the basics on how a fuel pump works let’s get into what happens when your fuel pump goes bad.
4 Most Common Bad Fuel Pump Symptoms
1. Fuel Pump Noise
The most common bad fuel pump symptom is a whining noise coming from the back of your car.
This happens because the fuel pump is struggling to work so it starts to make a loud noise.
A good way to verify the source of the sound you’re hearing is coming from your fuel pump is to remove your gas cap, put your ear up to the fuel filler, and take a listen. If it’s a lot louder and clearly coming from the inside of the tank, then you’ve likely got a failing fuel pump in there.
2. Hard Start
If your car is having a hard time starting, or if it starts and then stalls, there’s a chance your fuel pump might be the reason.
Think about it… if fuel isn’t being delivered to the engine, it’s not going to start!
HOWEVER… a hard start can be happening for a number of different reasons. Remember, your fuel pump is part of your car’s fuel system. So a hard start could also be caused by a failure of other parts of the system.
To pinpoint (or rule out) that your fuel pump is the reason for your hard starts, testing the pressure in your fuel system is a good idea. There’s a little schrader valve (looks just like the air valve on your tires) on the fuel rail where you can test your fuel system’s pressure.
If you don’t have a fuel pressure test kit and don’t want to buy one, many of the big box retailers like O’Reilley Auto Parts have loaner tool programs.
Look up your vehicle’s proper fuel pressure online and if you’re outside of the range, you’ve found your problem.
But don’t go pulling out your fuel pump just yet! If you discover that your fuel pressure is low, it could also be a sign of a clogged fuel filter… which is an easier thing to fix than a fuel pump.
3. Engine Sputtering
Another classic bad fuel pump symptom is when your engine starts to sputter and shake while running.
Engine sputtering doesn’t have to be a constant “thing”. It could happen on and off.
Regardless, if your engine is sputtering, it means something is wrong and you need to get it fixed before you end up stranded on the side of the road somewhere.
Unfortunately, just like a hard start, engine sputtering could be caused by any number of things. A bad fuel pump is only one of them. Your spark plugs, wires, coil packs, air filter, throttle body, etc. could be causing the issue. So be sure to give your car a thorough check to pinpoint the cause of your problem.
4. Car Hesitates when Accelerating
If your car hesitates when accelerating or when you are towing something, it could be one of the signs of a bad fuel pump.
When you’re accelerating to get onto an onramp, you are putting your car under a high power demand. So it’s going to need more fuel. Fast.
The same is true when you’re towing something. Your car (or truck!) needs more power (and therefore more fuel) to tow all that extra weight.
In both of these conditions, your engine is working its hardest and demands a lot of fuel at once. This means your fuel pump is also working its hardest to send fuel to the engine.
So think about it…. If your fuel pump is struggling when it is working its hardest, it’s a pretty good sign that your fuel pump is going bad.
Fuel Pump Replacement Cost
Fuel pump replacement cost depends on what kind of car you drive. Cost of the fuel pump itself can range from around $50 to $200 or more.
Fuel Pump Access
As you know, with car problems, cost of the part is only a piece of the total cost. You also have to consider labor cost. And fuel pump replacement is one of those projects where labor cost varies wildly from car-to-car.
Easy Access
If you’re lucky, your car will have an easy-to-access fuel pump. In some cars, the fuel pump can be accessed by removing your car’s rear seat. Under the seat, there will be a small opening that will allow you to access the pump inside of the fuel tank.
If your car has easy access to the fuel pump like this, you’re probably looking at a couple hours of labor so you can likely have the job done (part included) for 500 bucks or less.
And if you’re handy, it can be a fairly easy DIY project to do in your own garage.
Difficult Access
On the flip side, some cars require the entire fuel tank to be dropped. As you can imagine, this can get difficult and expensive. I’ve seen some cars that require suspension and drivetrain parts to be removed in order to access the fuel tank and ultimately the fuel pump.
If your car happens to be one of these, I hate to tell you, but you’re looking at thousands to replace your fuel pump.
And I wouldn’t attempt this as a DIY project unless you’ve got a lot of experience working on cars and all the right tools.
Conclusion
The most telltale bad fuel pump symptom is fuel pump noise. If you are experiencing any of the other three bad fuel pump symptoms described in this article, you need to rule out all other possible causes before doing a fuel pump replacement. Take your time and inspect all other parts of your fuel system to pinpoint the exact cause of your car’s problem. Fuel system problems can get tricky. I hope some of what I’ve shared here is helpful. Good luck!
About the Author
Kevin
Hi I’m Kevin and I’m a car guy. I first got the bug as a kid when I helped my dad rebuild the motor in his 1969 Mustang. I shadowed him for countless hours doing all kinds of hands-on work in the garage. As I got older, I started working on my own cars – from new transmissions to stereos to fine detailing. I started this website to share some of the things I’ve learned over the years.