Fuel Pump Replacement: Is It Safe Or Risky?

Changing a fuel pump can be a challenging task, and there are several safety precautions to consider. Fuel vapours are highly flammable and toxic, so it is important to work in a well-ventilated area, preferably outdoors, to minimise the risk of fire or inhalation of harmful fumes. It is also crucial to wear safety gear, such as safety glasses, gloves, and appropriate clothing, to protect yourself from fuel spills and splashes. Before attempting to change a fuel pump, it is important to understand the potential dangers and take the necessary precautions to ensure a safe and successful outcome.

Warning signs of a failing fuel pump

A failing fuel pump can wreak havoc on your car's performance and, if left unattended, may leave you stranded on the side of the road. Here are some warning signs to watch out for:

• Engine overheating: A failing fuel pump may overheat and, due to its inefficiency, cause the engine to overheat as well. Your vehicle may operate for about 15-30 minutes before stopping. After allowing it to cool down, you may find that it runs again, only to repeat the failure as the engine heats up.
• Sputtering: Noises, backfires, and sputtering engines indicate a fuel pump malfunction. An inconsistent fuel flow may cause internal engine problems, leading to hesitation when starting the vehicle or upon acceleration.
• Engine light comes on: The "Check Engine" light illuminating on the dashboard may be accompanied by any of the issues mentioned above.
• Inability to maintain speed: The engine may "choke" or struggle to maintain speed, making you think you are out of gas, despite the gauge showing fuel in the tank.
• Whining noise from the fuel tank: A damaged fuel pump might make a loud, whining noise that you'll hear from your gas tank. The normal noise your pump makes is a low hum.
• Poor fuel efficiency: A failing fuel pump can lead to lower fuel efficiency as it may push too much fuel into the engine, causing you to burn more gas than normal.
• Engine misfire: A fuel pump malfunction can cause an engine misfire as it may not be able to supply enough fuel to the engine, resulting in a rough idle or difficulty starting the car.
• Stalling: Your vehicle may stall when it gets hot as a faulty pump might struggle to supply enough fuel to the engine under high-temperature conditions.
• Power loss: A faulty fuel pump may cause power loss while accelerating or driving up steep inclines as it cannot keep up with the demands of the engine at higher speeds or under stress.
• Vehicle surges: Your vehicle may surge forward for no apparent reason when the pump occasionally delivers too much fuel, causing the car to surge and then slow down.

What to do if your fuel pump is malfunctioning

A malfunctioning fuel pump can cause havoc with your car's performance and even leave you stranded on the side of the road. Here's what to do if you suspect your fuel pump is malfunctioning:

Recognise the Signs

First, you need to be able to recognise the signs of a malfunctioning fuel pump. Some common symptoms include:

• Engine Sputtering or Stalling: This could be an indication of an inconsistent flow of fuel to the engine, which is often caused by a failing fuel pump.
• Power Loss: A faulty fuel pump may not be able to keep up with the demands of the engine, leading to power loss, especially at higher speeds or when driving up steep inclines.
• Car Not Starting: If the pump is unable to deliver fuel to the engine, the car won't start.
• Noise in the Fuel Tank: An unusually loud whining noise coming from the fuel tank could indicate a bad fuel pump.
• Poor Fuel Efficiency: A malfunctioning fuel pump may consume more power, resulting in decreased fuel efficiency.

Get it Checked

If you notice any of the above symptoms, it's important to get your car checked by a professional mechanic as soon as possible. They will be able to diagnose the issue and recommend the necessary repairs or replacements.

Potential Solutions

Depending on the severity of the damage, there are a few potential solutions:

• Fuel Pump Replacement: If the pump is severely damaged or worn out, replacement is usually recommended. While this can be costly, it can prevent future breakdowns and potential damage to other components of your car.
• Fuel Pump Repair: In some cases, if the damage is minor, repairing the fuel pump by replacing faulty parts may be an option. However, this is typically only a temporary solution.
• Fuel System Cleaning: Regular fuel system cleaning is important to maintain the efficiency and performance of your vehicle. Carbon deposits and residues can build up in the fuel system over time, leading to reduced power and performance.
• Regular Maintenance: Regular maintenance of the fuel pump and the entire fuel system, including inspections, cleaning, and timely replacements, can help prevent future problems.

How to test if your fuel pump is faulty

A fuel pump is important for your car, and your vehicle won't be able to move without one. However, some vehicles can still run for a few blocks or even miles with a malfunctioning fuel pump. Driving with a poorly performing fuel pump can damage your engine, so it's important to look out for signs of trouble and test your fuel pump if you suspect it's faulty.

Signs of a Faulty Fuel Pump

• Your car won't start, or it hesitates and is rough when accelerating.
• Your car stalls at high speeds or under load (e.g. driving up steep inclines or with a loaded cargo).
• Your engine is overheating.
• Your engine is sputtering, backfiring, and making unusual noises.
• Your fuel efficiency has decreased, and you're making more trips to the gas station.
• Your "Check Engine" light is on.

Testing Your Fuel Pump

Step 1: Check if the problem is fuel-related

If your engine won't start, listen for the fuel pump by putting your ear near the fuel tank and turning the ignition key to the "on" position. The fuel pump should make an audible noise (a low hum) if it's working properly. If you hear a loud whining noise, this could indicate a problem with the fuel pump.

Step 2: Check fuel pressure and/or volume

Checking the fuel pressure and/or volume will tell you whether enough fuel is making it from the tank to the engine. You can use a fuel pressure gauge to perform this test. Mechanical fuel pressure gauges are inexpensive and readily available. Simply connect the gauge as outlined in your repair manual and compare the reading to the specification listed in the manual. If the reading is significantly lower than the specification, you may have a bad fuel pump.

Step 3: Advanced tests

If you have access to an oscilloscope and low amp clamp probe, you can test the fuel pump by connecting the probe to the pump's power wire. A good pump should produce a pattern of even "humps" if it's working properly. If the pump is bad, the humps will be jagged and uneven.

Alternatively, some high-end scan tools allow remote fuel pump testing. You can activate the pump with the push of a button to see if it runs.

If you suspect your fuel pump is faulty, it's best to take your vehicle to a certified mechanic or dealership for diagnosis and repair. Driving with a bad fuel pump can cause poor fuel efficiency, stalling, and engine damage.

How to safely replace a fuel pump

Warning Signs

Your fuel pump is important for your car, and it may seem as if your vehicle can't move without one. That's not always true, though. Some vehicles can limp along with a malfunctioning fuel pump for a few blocks or even miles. However, driving with a poorly performing fuel pump is not good for your vehicle, so it's important to look out for signs of trouble before you end up stranded or stalled in traffic.

The first and most obvious symptom is that your car may not start at all, or it might start poorly. Your car may also stall during operation because the fuel pump is bad.

Vehicles can sputter and stall for a variety of reasons, so here’s a follow-up test: pull your vehicle into the garage or another silent environment. When it’s not running, put the key in the ignition and turn it to the “ON” or “accessory” position. If you have fuel injection and an electric fuel pump, the pump should start up, making a clicking or buzzing sound.

After performing the above test, if you can’t hear the fuel pump turn on, try this test: using a fuel pressure gauge, test to make sure there’s enough fuel reaching the engine. You can take your vehicle to a technician for this test or purchase a fuel pressure gauge at an auto-parts store and do it yourself.

Safety Precautions

Before attempting to replace your fuel pump, it is important to take the necessary safety precautions. Fuel is flammable, so the task can be dangerous. Make sure to take the necessary precautions and have a fire extinguisher on hand. It is also important to work in a well-ventilated area, preferably outdoors, to minimize the risk of fire or inhaling harmful fumes. Always wear safety glasses, gloves, and appropriate clothing to protect yourself from fuel spills and splashes.

Replacing the Fuel Pump

The process of replacing a fuel pump will vary depending on the type of car you have. In some cases, you will need to remove the fuel tank. In other cases, there may be an access port under the rear seat or in the trunk area.

If you need to remove the fuel tank, the following steps should be taken:

• Put on your safety glasses and have a fire extinguisher nearby.
• Safely raise and support the rear of the vehicle using a jack and jack stands. Set the parking brake and chock the front wheels.
• Disconnect the negative battery cable.
• Relieve fuel system pressure following the procedure found in the factory repair information.
• Drain the fuel tank if it has a lot of fuel. Usually, this is done using a hand-operated pump or siphon. If you choose to leave the tank full, it will be a lot heavier and harder to balance.
• Loosen the clamp on the fuel filler neck, then disconnect the neck from the fuel tank.
• Support the fuel tank with a transmission jack or equivalent.
• Remove the fuel tank strap bolts and the straps themselves.
• Lower the tank just enough to access and disconnect the fuel hoses, electrical connections, and emissions hoses.
• Once everything is disconnected, lower the tank completely.
• Clean the area around the pump access hole to prevent dirt and debris from entering the tank.
• Remove the retainer ring or bolts securing the pump assembly to the tank.
• Remove the fuel pump and seal ring from the fuel tank.
• Compare the replacement pump to the new pump assembly to ensure a match.
• Install the new seal ring and new pump assembly in the tank.
• Using a transmission jack or equivalent, raise the tank just enough to reconnect the fuel hoses, electrical connections, and emissions hoses.
• Raise the tank into place.
• Reinstall the fuel filler neck and secure it with a clamp.
• Reinstall the fuel tank straps and torque the mounting bolts to the specification listed in the factory repair manual.
• Safely remove the jack stands and lower the vehicle.
• Reconnect the negative battery cable.
• Fill the fuel tank as needed.
• Start the vehicle and double-check your work, looking for leaks.

If your car has an access port, the process is similar, but you won't need to remove the fuel tank. Simply remove the rear seat or rear seat cushion, access the fuel pump through the port, and follow the remaining steps above.

Tips

• Before beginning the replacement, consult your vehicle’s service manual or online tutorials for guidance.
• When replacing the fuel pump, consider replacing related components such as the fuel filter, fuel pump strainer, and fuel tank O-ring or gasket.
• Be honest with yourself about your ability to do the job right. Replacing a fuel pump can be difficult and time-consuming, and it may be more time and cost-effective to have a professional complete the repair.

The cost of replacing a fuel pump

The price of fuel pumps can vary, with some pumps priced between $180 and $350. The cost of labor is generally between $100 and $150 per hour, and the replacement process typically takes around two hours.

It is important to note that these estimates may not include taxes and fees, and the actual cost may differ depending on the specific vehicle and the service center. Additionally, dealership prices tend to be higher than those of independent shops.

Frequently asked questions