Is Your Fuel Pump Buzzing? Here's What You Need to Know

A buzzing or humming sound coming from the fuel tank area of your vehicle is typically a tell-tale sign of a failing fuel pump. However, a buzzing sound by itself doesn't indicate an imminent failure.

In fact, if your fuel pump is buzzing, you can keep your car running for a while. But sooner or later, it’s going to give out and leave you stranded on the side of the road. For that reason, we'd recommend replacing a buzzing fuel pump as soon as possible.

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Is Your Fuel Pump Failing?

Modern electric fuel pumps are found in the fuel tank. Their "job" is to keep the fuel system pressurized so that the engine has all the fuel it needs whatever it's doing.

The challenge is that the engine uses very little fuel at slow speeds (or while idling), but quite a bit of fuel when accelerating. An electric fuel pump needs to maintain constant system pressure, even as the fuel demand varies. This means the fuel pump is constantly loading up and slowing down.

Over time, this workload takes a toll. Not to mention, fuel pumps can be damaged by contaminated fuel and/or low fuel levels:

  • Contaminated fuel can cause fuel pumps to corrode, eventually leading to failure
  • Low fuel levels can cause the fuel pump to overheat, as fuel in the tank acts to keep the pump cool

While fuel pumps can last a vehicle's lifetime, contaminated fuels and/or overheating can cause a fuel pump to fail in as little as a year or two.

Buzzing Is A Symptom Of A Fuel Pump Problem

If you hear a buzzing or humming sound coming from the rear of your vehicle, it's probably the fuel pump. This sound isn't "good," but it's probably not an indication of an imminent failure. Most likely, there are other symptoms of a fuel pump problem to go along with your buzzing:

  • Slow or difficult engine starts
  • Slow acceleration and/or hesitation
  • The engine choking after running for a while
  • Decreased fuel efficiency

If your car exhibits any of these symptoms in addition to a buzzing fuel pump, then a failing pump is the likely culprit. While you can wait for failure, it's important to understand that a fuel pump failure can happen anytime, anywhere, without notice. For that reason, it's a good idea to replace a fuel pump at the first sign of trouble.

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A failing fuel pump will cost you more at the gas pump. That's because a failing pump leads to a 'lean' condition when the engine is accelerating. The engine computer compensates by demanding more fuel. If/when the fuel pump responds to the demand, fuel is wasted.

What To Look For In A Replacement Fuel Pump

A fuel pump that doesn't performing up to OEM specifications can cause all sorts of long-term problems.

First, a fuel pump that can't meet precise fuel system pressure requirements is going to cause a lot of annoying behaviors. If a fuel pump produces too much pressure at any given RPM, it can wear out prematurely. If a fuel pump produces too little pressure, it will cause hesitation, slow acceleration, and waste fuel.

Unfortunately, many after-market fuel pumps do not meet OEM specifications. Many of these pumps are "one size fits all" units that work "good enough" for most applications but never work perfectly. But because they're sort of "universal," they have very low prices.

So, our first tip: Don't pick the cheapest pump you can find.

Second, make sure you choose a fuel pump that comes with a real warranty. Some companies offer gimmick "limited lifetime" warranties, with a list of exclusions that's longer than a fuel return line. Our warranty policy is simple and honest.

Finally, try to buy direct from the fuel pump manufacturer. When you buy a fuel pump from a reseller, you almost always pay too much. Manufacturers who sell direct to consumer offer the best combination of service, pricing, and value for your dollar.

How to Maximize the Lifespan of Your Fuel Pump

Bad gas

When you install your new fuel pump, there are a few things you can do to prolong the life of your new pump as long as possible. Suggestions include:

  • Avoiding “dead” gas stations that don't sell a lot of fuel. A gas station that doesn’t get much business may have a fuel that's sitting in an underground tank for weeks. This increases the odds of fuel contamination.
  • Try to keep the fuel level above ¼ of a tank. Constantly running your car on empty may cause your fuel pump to overheat and underdeliver fuel to the engine.
  • Make sure the rest of your fuel system is working properly. A clogged fuel filter can shorten the life of a fuel pump, as can a malfunctioning oxygen sensor. Both of these issues can cause the pump to work much harder than it needs to.

While there are a variety of factors that impact fuel pump lifespan, these three behaviors will make sure your replacement fuel pump lasts.