Many people think of an engine as the beating heart of a car, pushing out power as you press on the accelerator. But when it comes to actually pumping fuel, that’s the job of the aptly named fuel pump. It moves the fuel from the tank to the engine. This means if your fuel pump stops working, so will your engine.
With that in mind, automakers often engineer their fuel pumps to last 100,000 miles or more. There are certain guidelines to follow to keep your fuel pump healthy, and there are certain symptoms that can tell you if it’s not. That’s our focus today.
What Does a Fuel Pump Do?
To better understand what happens when a fuel pump goes bad, let’s start with how the pump works. In a typical modern-day vehicle, the fuel pump is a small electric pump, much like one you might use in a flooded basement. It’s located in the gas tank, and when you turn on the vehicle, it relies on accessory power. The pump sucks in the surrounding fuel and pumps it via the fuel lines to the fuel injectors. Those control exactly how the fuel enters the engine cylinders.
What Are the Signs of a Bad Fuel Pump?
The first sign of a bad fuel pump will probably be a sound. It’s normal for a fuel pump to make a low humming noise as it runs, and you might be able to hear it coming from the gas tank area. As a pump gets older and begins to wear out, the sound can turn into more of a loud whining or droning.
Any problems with how the pump works will affect the flow of fuel to the engine. In a worst-case scenario, with a fuel pump that no longer runs at all, you won’t be able to start your car.
However, a pump often will operate for a while at a lower level of efficiency before you reach that point. That’s when you’re likely to notice trouble starting up your engine. Until enough fuel gets to it, you may have to hold the ignition on for longer than normal, or you may have to try more than once. And since the engine is being starved for fuel, it probably will start to sputter, cough and occasionally stall.
Nor will things get better once you start driving. In fact, it will be more of the same. The lack of fuel can cause the engine to misfire, which you’ll hear and feel. You’ll feel a difference in performance, too, with weaker acceleration and worse fuel economy. On the other hand, you may experience sudden surges in power. This could happen as the pump’s performance changes unexpectedly, so that it suddenly increases the amount of fuel it pushes to the engine.
What Are Some Tips for a Healthy Fuel Pump?
Overheating is among the top factors in causing a fuel pump to wear out. Automakers know this, and they take advantage of the pump’s location to help. Remember, the fuel pump is generally mounted on the bottom of the gas tank, where it’s submerged in gasoline. This keeps the pump cool, but only if there’s enough fuel to keep the pump covered. Additionally, if the fuel level gets too low, the pump can begin sucking in air with the fuel. This creates further problems by throwing off the correct mix of fuel and air in the engine. For these and other, non-pump-related reasons, many experts recommend never letting your fuel level get down below a quarter-tank full.
You should keep an eye on your car’s main fuel filter as well. Most fuel pumps will have some sort of filter to prevent dirt or debris from getting into the pump itself, but here we’re talking about the traditional external fuel filter. It’s more focused on keeping dirt from getting into the engine. If this filter becomes clogged or dirty, it will be tougher for the pump to push fuel through it. Then, the harder the pump works, the shorter its life.
It’s also worth noting that many of the problems caused by a bad fuel pump can be caused by a bad fuel filter, and for the same reason. Namely, not enough fuel is getting to the engine. A major difference is that a fuel filter is a lot easier and less expensive to replace than a fuel pump. While having a new filter installed will cost an average of a bit more than $100, you could spend 10 times that replacing a fuel pump.