Fuel Pump Replacement: Who Does The Job?

Replacing a fuel pump is a complex task that can be done by a qualified mechanic or by the vehicle owner. The fuel pump is a critical component of a vehicle's operation, transferring fuel from the fuel tank to the engine. It is usually located inside the fuel tank, and while durable, it is not indestructible. The cost of replacing a fuel pump ranges from $100 to $2000, with the price of the part itself ranging from $15 to $2000. The process of replacing a fuel pump involves relieving the fuel system pressure, disconnecting the battery, draining the fuel tank, removing the old fuel pump, and installing the new one. It is important to take safety precautions when performing this task due to the flammable nature of fuel.

Fuel pump replacement cost

The cost of replacing a fuel pump depends on several factors, including the make and model of the vehicle, the number of labour hours required, and whether any other parts related to the fuel assembly need to be replaced.

The average cost of a fuel pump replacement, including parts and labour, ranges from $220 to $1,500, with some estimates placing the average between $1,000 and $1,300. The cost of the parts alone can vary from $15 to $2,000, with an average of around $100 to $500. The cost of labour can range from $300 to $700, with some estimates placing the range between $600 and $1,500.

It is worth noting that the cost of replacing a fuel pump in a diesel engine with a mechanical fuel pump can be up to $1,500. Additionally, the cost of labour varies depending on location, with an average hourly rate of $90, but rates ranging from $60 to $140 per hour.

While it is possible to replace a fuel pump yourself, it is a moderately complicated task best performed by a professional mechanic, especially given the risk of fire when working with fuel systems.

Diagnosing a bad fuel pump

Check for Fuel-Related Issues

• Listen for the fuel pump: Put your ear near the fuel tank and turn the ignition key to the "on" position. A functional fuel pump should make an audible noise.
• Whack the fuel tank: Ask an assistant to crank the engine while you hit the fuel tank with a rubber mallet. If the vehicle starts, the electric motor inside the pump is likely faulty.
• Use starter fluid: Spray starter fluid into the throttle body while an assistant cranks the engine. If the vehicle starts and runs momentarily, the issue is fuel-related and could indicate a bad pump.
• Check for diagnostic trouble codes (DTCs): A faulty pump may set DTCs in your car's computer, either directly related to the fuel pump or referencing an air/fuel ratio problem.
• Check fuel trim with a scan tool: If the engine is running, check the short-term fuel trim (STFT) reading. Typically, fuel trim readings should be between -10 and 10. If the reading is above 10, the engine is running lean, and the fuel pump may not be delivering enough fuel.
• Check fuel pressure and/or volume: Use a fuel pressure gauge to determine if enough fuel is making it from the tank to the engine. If there is inadequate pressure or volume, the pump may be faulty, although further testing is required to rule out other issues.

Before Condemning the Pump

Before concluding that the fuel pump is faulty, it is recommended to check the following:

• Fuel pump electrical circuit: Check the integrity of the wiring in the pump circuit using a digital multimeter (DMM) to test for continuity, power, ground, and resistance.
• Fuel pressure regulator: For continuous fuel systems, check the regulator by disconnecting the attached vacuum hose and observing whether the pressure increases. If it doesn't, the regulator or its vacuum supply may be faulty.
• Fuel filter: Continuous fuel systems have an external filter that can be easily replaced. Rather than testing the filter, consider installing a new one to see if that resolves the issue.

Advanced Tests

• Measure current draw with an oscilloscope: Connect a low amp clamp probe to the pump's power wire to observe the waveform pattern. A functional pump should produce a pattern of even "humps," while a faulty pump will exhibit jagged and uneven humps.
• Use a professional-grade scan tool: Some high-end scan tools allow remote fuel pump testing by activating the pump with the push of a button.

Additionally, here are some signs and symptoms that could indicate a bad fuel pump:

• Difficulty starting the car
• Sudden loss of power while driving
• Rough run or stalling
• Strange, high-pitched whining noises coming from the fuel tank area
• The engine dies immediately after starting
• The car hesitates or struggles under acceleration
• The engine dies while driving
• Uncharacteristic noises from the fuel pump

How to replace a fuel pump

Diagnosing the Problem

If you're experiencing issues with your fuel pump, the first step is to diagnose the problem. Fuel pumps typically don't show warning signs before they fail, so it's important to pay attention to any strange behaviour from your engine. Some common symptoms of a faulty fuel pump include difficulty starting the car, sudden loss of power while driving, rough running or stalling, and strange, high-pitched whining noises coming from the fuel tank area.

If you suspect that your fuel pump is the issue, you can perform a few tests to verify. Park your vehicle on a firm, level surface and set the parking brake. Locate the fuel pump, which is usually in the fuel tank. Open the fuel cap and turn the key to the "on" position. If the fuel pump is working properly, you should hear a humming noise for two to three seconds. If there is no sound, the pump may need to be replaced.

Gathering Tools and Equipment

Before starting the replacement process, it's important to gather all the necessary tools and equipment. This includes a new fuel pump, fuel filter, and any other components specific to your vehicle. You will also need tools such as jack stands or ramps, a small floor jack or wood, wrenches, and screwdrivers. Additionally, ensure you have a safe and accessible workspace and take proper safety precautions, such as disconnecting the battery.

Relieving Fuel System Pressure

The next step is to relieve the fuel system pressure. This can be done by running the engine and pulling the fuel pump relay, or by pressing the Schrader valve on the pressure line momentarily to release the pressure.

Locating and Removing the Fuel Tank

Most fuel pumps are located directly in the fuel tank, so you will need to locate and remove the fuel tank from the vehicle. This process can vary depending on the vehicle, and you may need to use a jack to support the tank during the removal process. On some models, there may be an access port under the rear seat or in the trunk area, which can make the job easier.

Removing the Old Fuel Pump

Once you have accessed the fuel pump, take note of the fuel line connections and wiring before removing the old pump. Disconnect all the connections, remove the old pump, and pull it out.

Installing the New Fuel Pump

Install the new fuel pump by sliding it into the output hose and reconnecting the clamps to the hose and the sending unit. Install a new filter sock to the base of the pump and reassemble the fuel system.

Testing the New Fuel Pump

Finally, test the new fuel pump to ensure that everything is functioning properly. Fill the tank with gas and conduct a road test to confirm a successful repair.

Tips for Replacing a Fuel Pump

• Work in a well-ventilated area to minimize the risk of fire or inhalation of harmful fumes.
• Always wear proper safety gear, such as safety glasses and gloves, to protect yourself from fuel spills and splashes.
• Drain the fuel tank to reduce the risk of spills and make it easier to handle.
• Clean around the fuel pump to prevent dirt and debris from falling into the fuel tank.
• Consider replacing related components, such as the fuel filter, fuel pump strainer, and fuel tank O-ring or gasket.

Safety precautions when replacing a fuel pump

Replacing a fuel pump can be a challenging task, but with the right precautions, it can be made safer. Here are some safety precautions to follow when replacing a fuel pump:

Prepare the Workspace

Before starting the replacement, ensure your workspace is safe and accessible. Work in a well-ventilated area, preferably outdoors, to minimize the risk of inhaling harmful fumes and to reduce the risk of fire.

Wear Proper Safety Gear

Always wear safety glasses, gloves, and appropriate clothing to protect yourself from fuel spills and splashes.

Disconnect the Battery

Disconnect the battery to avoid any sparks while working around the fuel tank.

Reduce Fuel Level

If possible, drain or siphon out most of the fuel from the tank. This will reduce the risk of spills and make the fuel tank lighter and easier to handle.

Clean the Fuel Pump Area

Before removing the fuel pump, clean the area around it to prevent dirt and debris from falling into the fuel tank.

Relieve Fuel System Pressure

This can be done by running the engine and then pulling the fuel pump relay, causing the engine to stall. Alternatively, with the engine off, press the Schrader valve on the pressure line momentarily and capture the small fuel spray that comes out.

Consult Vehicle Manual

Refer to your vehicle's service manual or online tutorials for specific guidance on replacing the fuel pump in your particular vehicle make and model.

Replace Related Components

When replacing the fuel pump, consider replacing related components such as the fuel filter, fuel pump strainer, and fuel tank O-ring or gasket.

Tools needed to replace a fuel pump

Replacing a fuel pump can be a challenging task, but with the right tools and precautions, it can be made safer and more manageable. Here is a list of tools you will need to replace a fuel pump:

• A jack and jack stands
• A ratchet, various-sized sockets, and various-sized wrenches
• A set of pliers and/or a hose clamp removal tool (only required for some vehicles)
• A fuel line disconnect tool (only required for some vehicles)
• A small floor jack or a transmission jack to support the fuel tank (a regular jack and a block of wood can sometimes be used instead)

Additionally, it is important to have a safe and accessible workspace and to take proper safety precautions. Always wear safety glasses, gloves, and appropriate clothing to protect yourself from fuel spills and splashes. Ensure you are working in a well-ventilated area, preferably outdoors, to minimise the risk of fire or inhaling harmful fumes.

Frequently asked questions