The fuel pump, located inside a car’s fuel tank, is the heart of the fuel system, responsible for delivering fuel from the tank to the engine at the right pressure and quantity. Like an unsung hero in the larger picture, it works in the backdrop of the entire combustion process of the air-fuel mixture in an engine.
Even a minor fault in the fuel pump can lead to noticeable performance issues, both when starting the engine and during normal driving. In this article, we’ll cover the common symptoms of a bad fuel pump and explain how recognizing them early can help you avoid costly repairs or replacements.
What is a Fuel Pump in a Car: Components and Functions
Older vehicles typically used mechanical fuel pumps mounted over the engine and were dependent on the engine’s motion for their functionality. However, all modern cars now come with electronic fuel pumps that are operated through the vehicle’s Electronic Control Unit (ECU), which regulates both pressure and quantity of fuel as required by the engine.
Components of an Electronic Fuel Pump:
- Pump Motor: Powers the pump, drawing fuel from the tank whenever the engine is running.
- Pumping Mechanism: Generates the flow and pressure needed to deliver fuel to the engine efficiently.
- Fuel Filter: Located at the pump’s inlet, it prevents contaminants from entering the pumping system.
- Pressure Relief Valve: Regulates pressure within the pump and directs excess fuel back to the tank.
- Check Valve: When the engine is turned off, it maintains the line pressure by preventing fuel from flowing back into the tank.
- Electrical Wiring: A combination of wires, required for transferring the electrical signal from the vehicle’s ECU to the pump motor, ensuring precise control of fuel delivery.
Signs of a Faulty Fuel Pump
Most of the symptoms of a faulty fuel pump affect the engine’s performance, either directly or indirectly, impacting its health and overall outcomes. The following are those indications:
1. Difficulties in Starting the Engine
The inability of a fuel pump to build the required pressure, most likely due to the pump motor or the pumping mechanism malfunctioning, affects the supply of fuel to the engine, resulting in the engine requiring multiple cranks to start.
2. Drop in Fuel Efficiency
A reduced fuel supply can disrupt the air-fuel mixture, causing the engine to run lean. This inefficiency can lower overall fuel economy, making your vehicle consume more fuel than usual.
3. Loss of Power or Jerky Acceleration (Engine Sputtering)
The adverse effects of a faulty fuel pump are not only at the start, but also while the vehicle is maintaining a consistent speed during long drives. Insufficient fuel delivery can affect acceleration, making the car feel sluggish or unresponsive, especially under load or during overtaking.
4. Whining Sounds from the Fuel Tan
When the fuel pump has to work harder to supply fuel to the engine, it begins producing unusual whining or humming noises near the fuel tank. It is a clear audible warning of the potential failure of the fuel pump
5. Engine Misfiring
The effects on the supply of fuel from the fuel tank to the engine due to a faulty fuel pump can also affect the performance of fuel injectors, which eventually fail to maintain a consistent air-fuel mixture. As a result, the engine begins to misfire or feel rough while idling.
6. Vehicle Stalling
If the fuel pump fails severely, disrupting both the pressure and flow of fuel to the engine, the engine may receive little to no fuel. This can cause the vehicle to stall suddenly, creating a serious safety risk.
Causes Behind a Fuel Pump Going Bad
The reasons for a fuel pump going bad can be due to inevitable situations, natural wear-and-tear, and even human mistakes, all of which are as follows:
- Frequently Driving with Low Fuel: Driving your vehicle with low fuel levels most of the time exposes the pump to air within the tank, while it should always be immersed in fuel for optimal lubrication. Due to exposure to air, the fuel pump wears out faster, and in rare cases, it may overheat as well.
- Contaminated Fuel: If your vehicle is frequently fed contaminated fuel, the dirt and debris in the fuel will clog the fuel pump and fuel filter, damaging internal components and reducing the pump’s lifespan.
- Usual Wear and Tear: Fuel pumps typically last between 100,000 and 150,000 miles, depending on the vehicle. As they near the end of their life cycle, their ability to maintain proper fuel pressure and flow declines.
- Electrical Issues: Sometimes, even faulty wiring and weaker electrical connections between the fuel and ignition system can reduce pump efficiency, impairing fuel delivery over time.
Driving with a Defective Fuel Pump: Is it Safe?
Driving with a faulty fuel pump not only puts your vehicle at risk, but it can also pose a threat to your personal safety.
While minor issues may go unnoticed initially, continuing to drive with a failing fuel pump increases repair costs and safety risks over time.
. The following are some of the adversities you might face with a defective fuel pump:
- A failing pump can abruptly cut off fuel supply, causing the engine to stall unexpectedly.
- Insufficient fuel delivery can make the vehicle sluggish, especially during uphill driving, towing, or off-road conditions
- Over time, the car may fail to start due to inadequate fuel reaching the engine.
- Irregular fuel flow can strain fuel injectors and, in severe cases, harm the engine.
- Electrical faults or overheating in the fuel pump can potentially lead to a fire hazard.
How to Fix a Faulty Fuel Pump in a Car
Once you identify the symptoms of a failing fuel pump, a workshop can perform a proper diagnosis using an OBD-II scanner to check for fuel system-related error codes
- Common checks include inspecting the fuel filter for clogs, as restricted fuel flow can mimic pump failure, and examining the wiring harness for burnt fuses, corroded connections, or damaged wires.
- If the fuel pump itself is determined to be faulty, replacement is typically the most reliable solution, as repairing modern in-tank pumps is rarely feasible.
How Much does a Fuel Pump Cost?
While the fuel pump holds great significance in the functioning of both the fuel system and the engine, its replacement is not a costly affair.
- The entire replacement process for a faulty fuel pump typically ranges between $300 and $700 for standard vehicles and can increase to $1,500 for luxury vehicles.
- The cost of a fuel pump as an entity varies between $50 and $150 for mechanical pumps used in older cars. However, they typically range between $150 and $400 for modern electronic fuel pumps and between $400 and $1,000 for high-performance fuel pumps used in performance-oriented vehicles.
- The labor charges for replacing a faulty fuel pump range from $150 to $300.
Prevention of a Fuel Pump from Going Bad: Here’s How You Can Do It
While you can’t escape from the regular wear and tear of a fuel pump, you can make it last as long as possible with healthy driving and ownership practices. Driving with more than an adequate amount of fuel in the gas tank (at least more than one-quarter), using high-quality fuel, replacing the fuel filter as and when required, checking electrical connections from time to time, and smooth driving with controlled throttle and braking inputs will make your car’s fuel pump last longer.
FAQs
Q1. What are the signs of a clogged fuel filter?
The early indications of a clogged fuel filter are reduced acceleration, inconsistent power delivery, engine stalling, a drop in fuel efficiency, and engine sputtering at higher RPMs.
Q2. What is the most common cause of fuel pump failure?
A fuel pump usually fails due to reasons such as frequently driving with low fuel levels, contaminated fuel, poor wiring, and normal wear and tear.
Q3. Will a bad fuel pump affect acceleration?
Since a faulty fuel pump is unable to supply the required measured quantity of fuel during acceleration, the engine starts feeling sluggish, which is a sign of a drop in acceleration.
Q4. What’s the average cost to replace a fuel pump?
The cost of replacing a fuel pump ranges from $300 to $700 for standard vehicles and can increase to $1,500 for luxury vehicles, including the price of a fuel filter and labor charges.
Q5. What is the life expectancy of a fuel pump?
Ideally, a fuel pump lasts for 100,000 to 150,000 miles, provided the vehicle is maintained regularly and driven with proper driving practices.