A failing fuel pump can turn a routine drive into a stressful roadside breakdown, and can leave you stranded at the worst possible time. Understanding the warning signs early can save you time, money, and frustration. In this article, we’ll explore how a fuel pump works, the common symptoms of failure, and what steps you can take to diagnose and prevent problems before they leave you stranded.

If you suspect your fuel pump is failing, don’t wait—schedule a diagnostic with Auto Monkey to ensure your vehicle remains reliable on the road.

The fuel pump is a critical component of your vehicle's fuel system. It transfers gasoline from the fuel tank to the engine at the correct pressure to ensure proper combustion. In most modern vehicles, the fuel pump is electrically powered and located inside the fuel tank. When it fails, the engine won’t receive the necessary fuel, leading to starting issues or stalling while driving.

It is important to say before we list these, that many of these signs can also be attributed to other sensors or parts that have failed. For example, difficulty starting, engine stalling and RPM hesitation can also be attributed to a bad ground connection, camshaft position sensor, misfiring cylinders, fuel injectors, throttle body and acceleration sensors. Professional technicians know the signs and are trained on how to weed through certain signs and symptoms eliminating the related items to the core problem of a bad fuel pump and filter. 

Now that we've shared this disclaimer, let's get on with some common symptoms and how to spot a failing fuel pump.

1. Difficulty Starting the Engine
   One of the first signs of a fuel pump issue is trouble starting your vehicle. If the pump is weak or malfunctioning, it may not deliver sufficient fuel pressure to start the engine. This issue often worsens over time, requiring multiple attempts to get your vehicle running.
   
   
2. Engine Sputtering at High Speeds
   If your engine suddenly sputters or hesitates while driving at highway speeds, it could indicate inconsistent fuel delivery. A struggling fuel pump may fail to maintain the required fuel pressure, leading to momentary power loss.
   
   
3. Loss of Power When Accelerating or Climbing Hills
   A failing fuel pump often struggles to provide enough fuel when the engine is under increased demand. If you notice a significant loss of power during acceleration or when climbing steep inclines, it may be a sign that the pump isn’t delivering enough fuel.
   
   
4. Engine Stalling
   Random stalling, especially when driving, is another major warning sign. If your vehicle shuts off unexpectedly and struggles to restart, your fuel pump could be on its last legs.
   
   
5. Whining Noise from the Fuel Tank
   A healthy fuel pump operates quietly, but if you hear a high-pitched whining or buzzing noise coming from your fuel tank, it may indicate wear and tear or impending failure.
   
   
6. Surging or Hesitation
   If your vehicle unexpectedly surges forward without pressing the accelerator, it could be due to inconsistent fuel delivery. Conversely, if it hesitates when you press the gas, the pump may be struggling to maintain fuel pressure.
   
   
7. Poor Fuel Efficiency
   A failing fuel pump can cause inefficient fuel delivery, leading to increased fuel consumption. If you notice a sudden drop in miles per gallon without a change in driving habits, it’s worth investigating your fuel system.
   
   
8. Check Engine Light Activation
   We likely should have listed this item first. It's important to note, many of these symptoms can be attributed to other failing systems on the engine; however, a failing fuel pump will almost never trigger a the check engine light. This is because the check engine, or service engine light is more often associated with engine sensors and emissions systems gone wrong. When the fuel pump fails, there's no engine light or code that says your fuel pump failed. Professional technicians know the signs and are trained on how to weed through certain signs and symptoms eliminating the related items to the core problem of a bad fuel pump and filter.

• Fuel Pressure Test: Use a fuel pressure gauge to check if the fuel pump is delivering adequate pressure. Compare the readings to your vehicle manufacturer’s specifications. (Best practice method. This takes expensive specialty equipment and unique understanding to accurately read what is happening.)
• Listen for the Pump: When turning the ignition key to the "on" position (without starting the engine), listen for a brief humming or buzzing noise from the fuel tank. Fuel tanks are most frequently located in under the back seat in sedans, and under the rear part of the carriage in a truck or SUV. If you don’t hear it, the pump may not be working. (This more "YouTube University" method, is not a fail safe practice, but is commonly used by experienced technicians.)
• Inspect the Fuel Filter: A clogged fuel filter can mimic the symptoms of a failing pump. Replacing the filter might resolve performance issues. Any more, most vehicles manufacturers have combined the fuel pump and filter into one assembly. There are some OEMs that separate them and they're usually in older models (pre 2010) like, Subaru, Volvo, BMW or Porsche. 
• Check for Electrical Issues: Ensure that the fuel pump’s wiring and relay are functioning correctly before assuming the pump itself is faulty.

Although fuel pumps don’t last forever. They corrode over time. The filter will usually fail before the pump does, but again, they are typically a packaged deal. Still, there are a few things you can do to help extend their lifespan:

1. Keep Your Fuel Tank Above a Quarter Full – Running on empty can cause the pump to overheat and wear out faster. Now, as a college student and newly wed I was running on "fumes" all the time. It was nearly a test to see how far, or long, I could actually drive my car on empty. But this practice can strain the fuel pump and cause it to fail early. 
   
   
2. Use High-Quality Fuel – Contaminated or low-quality gasoline can introduce debris into the fuel system, clogging the pump and filter.
   
   
3. Avoid Using Old or Contaminated Fuel – If your vehicle has been sitting for an extended period, drain old fuel and refill with fresh gasoline.
   
   
4. Follow Your Vehicle’s Maintenance Schedule – Regular check-ups can catch fuel system issues before they become severe.

If your fuel pump completely fails and your car won’t start, you may considering using the Auto Monkey app to request a mobile mechanic. Auto Monkey has trained and experienced technicians that can help you replace your fuel pump without all the drama and trouble of calling a tow truck. Attempting to replace a fuel pump without the proper tools and experience can be dangerous, especially when the fuel tank must be dropped from the bottom of the vehicle.

If you're experiencing any of these symptoms, it's best to get your vehicle inspected by a professional mechanic. Auto Monkey’s qualified mobile mechanics can diagnose and replace a faulty fuel pump at your convenience. Book an appointment today through our mobile app or contact us for assistance.

Need a mobile mechanic? Get a quote today at Auto Monkey!