Fuel Pump Buyer’s Guide
- The fuel pump is the mechanism that initiates the fuel delivery process.
- It siphons, filters, and pressurizes the fuel in preparation for combustion.
- There are two types of automotive fuel pump mechanisms: mechanical and electric fuel pumps.
- Mechanical fuel pumps are typically installed in vehicles that have carburetors, while most modern vehicles have electric fuel pumps.
- The symptoms of a bad fuel pump include an engine that dies or fails to restart, losing power when pulling away from a standing stop or when the engine is under high strain, and engine misfires.
- You can also conduct a fuel pump assembly test to gauge your component's functionality.
- Replace a faulty fuel pump immediately to avoid unexpected stalling, maintain good fuel pressure and volume for your engine, and enjoy smooth drives.
- Consider your fuel pump's specifications, size, fit, brand, and price to find a good replacement. It also pays to know what questions to ask yourself and your dealer.
- OEM replacement fuel pumps typically cost anywhere between $40 to $2,600.
- You can install your fuel pump replacement on your own with the right tools and know-how.
Have you ever wondered how gas travels from your car’s fuel tank all the way to the engine? This is possible thanks to the automotive fuel pump. This part of the vehicle is something we rarely see, and yet it plays an important role in making your car run.
As you start your car’s engine, the fuel pump is one of the first mechanisms in your vehicle that start to move. Let’s take a closer look at how it works and find out why keeping it in tip-top shape is important for your car.
What is a fuel pump?
The fuel pump is the mechanism that initiates the fuel delivery process. This part is responsible for delivering pressurized gas to the fuel injectors in the car engine. The fuel pump module is typically located inside the fuel tank, while older car models may have it next to the engine.
Modern fuel pumps are housed in a plastic canister. Attached to the fuel pump module is a fuel level sensor that communicates with the gas gauge and empty level lights on your dashboard. The fuel pump can be accessed through a service port or by removing the gas tank.
How do fuel pumps work?
An automotive fuel pump is a mechanism that delivers fuel from a vehicle’s gas tank to the engine. It is a component of the fuel delivery system that siphons, filters, and pressurizes the fuel in preparation for combustion. This process varies depending on the type of fuel pump mechanism installed in your car.
What are the types of fuel pumps?
There are two types of automotive fuel pump mechanisms: mechanical and electric fuel pumps. While similar in function, the two mechanisms deliver fuel through different motions. A mechanical fuel pump pulls gas from the fuel tank to the engine, while a mechanical fuel pump pushes gas towards it.
Mechanical Fuel Pumps
Mechanical fuel pumps are typically installed in vehicles that have carburetors. These fuel pumps are directly connected to the carburetor and work by siphoning fuel from the gas tank and delivering it to the engine. Because of its location, it requires less pressure to pump fuel.
Inside the pump are cams which are mechanical links that convert rotational motion into linear motion. As each cam rotates, the fuel pump lever attached to it moves up and down, creating suction for the rubber diaphragm to pump fuel in a single direction.
Electric Fuel Pumps
Most modern cars are fitted with an electric fuel pump. It is typically found in the rear of the vehicle, either inside or adjacent to the gas tank. The fuel feed pump siphons gas from the tank, forcing it through the fuel filter that removes any fuel tank residue.
Once filtered, the fuel is delivered to the metering pump which pressurizes it by jostling and spinning it around. When it reaches the required pressure, a plunger flushes it out of the fuel pump and into the fuel line. Any excess fuel escapes back into the tank with the help of the fuel pressure regulator.
How to know if your fuel pump is going bad?
There are several signs that could mean that your fuel pump is going bad, but the biggest one is when the engine dies and fails to restart. Basically, the car will act as if it has no fuel even if its gas tank is still filled.
Other signs include losing power when pulling away from a standing stop, losing power when the engine is under high strain, and a misfiring engine.
How to conduct a fuel pump assembly test
Before you yank out that old fuel pump assembly and put a new one in, make sure that that’s what’s causing your car troubles. This means you have to check the entire assembly and related components by doing an electrical and pressure test. Here’s how:
- Fuel pressure gauge
Step 1: Inspect the fuse of the fuel pump. Locate the fuse box with the help of your vehicle manual. Then fine the fuse for the fuel pump. Check the fuse for signs of damage such as scorch marks. If the fuse is blown, check the relays to eliminate wire problems. Replace a blown fuse or a worn-out wire as soon as possible.
Step 2: Check the pump for voltage. A faulty pump assembly can actually be caused by a voltage shortage. So to make sure that enough electricity is going to the pump, check its voltage with a voltmeter. Connect the metering device onto the pump’s positive and negative terminals—make sure that the right probe is connected to the right terminal. Check the voltmeter’s screen for the reading. If the reading is lower or higher than the range indicated in your vehicle manual, then the pump has to be replaced.
Step 3: Check the pump wires. Do another drop test on the pump wires using the voltmeter. The process is similar: simply connect the voltmeter’s probes into the appropriate wires and check the readings. If the grounding wire is properly grounded and all the wires show the full voltage, then a faulty fuel pump is most likely the culprit behind your car problems.
Step 1: Connect the pressure gauge to the pump fitting. The fitting is where the pump and the filter housing are joined together. This joint is where you will attach the pressure gauge. Since the location of the fuel pump and fitting depends on your car make and model, make sure to check your vehicle manual.
Step 2: Check the gauge. Let someone rev up the engine while you check on the gauge. Warm up the engine a bit. Then look at the pressure reading at idle speed and at a specific speed indicated in your pump specifications or vehicle manual. If the reading doesn’t match the specs indicated in the vehicle manual, you’ll have to install a new fuel pump assembly.
Advantages of replacing a faulty fuel pump
Avoid unexpected stalling
Are you having trouble starting your car? Stalling is a symptom that your car’s fuel pump may be clogged or damaged. A faulty fuel pump is a common culprit for unexpected stalling and difficulty starting or restarting your car. Replacing this part will give you peace of mind while on the freeway and will save you the cost of getting towed.
Maintain good fuel pressure and volume for your engine
Your car’s engine needs to have the right balance of air and fuel to function efficiently. As the fuel pump degrades, the check engine light may switch on. This happens when the fuel pump is no longer delivering enough gas to the engine. Replacing your fuel pump will ensure that your vehicle maintains the right ratio of air to gas for the engine.
Enjoy a smooth and quiet ride
Noise from the rear of your vehicle can be a sign of a faulty fuel pump. If you hear any humming or whirring sounds from your fuel tank, it’s best to have your mechanic check it out. A new fuel pump replacement may be just what you need for a quiet and comfortable drive.
What to look for in a new fuel pump?
One of the first things you have to check is whether the pump is mechanical or electric. You probably know what type of engine your car has, so you also know what kind of pump it uses.
Check the specifications of the fuel pump that your vehicle uses to make sure you get one that completely matches it.
Of course, there's also the matter of size. The right fuel pump must perfectly fit once it is installed in your vehicle.
It is highly recommended that you get only products from established brands. This way, you can ensure the quality and reliability of the product. Read reviews to find out the best, compare fuel pump prices, and get the one that will give you the most bang for your buck.
Questions to ask when choosing a fuel pump assembly
Getting the right amount of fuel into your vehicle’s engine is crucial to its overall performance. This is why you’ll need a reliable fuel pump assembly. Once this pump fails, don’t be surprised if you experience an engine that sputters when driving at high speeds, power loss when speeding up, an engine that won’t start, surging, and sudden power loss when your car is under strain. Sometimes, the only solution to these problems is to get a replacement. But before you grab the first pump assembly you see, ask yourself or a retailer these questions first to make sure you’re getting the right part:
Questions to ask yourself:
Do I need an in-tank or an inline fuel pump assembly?
Depending on your car make and model, you’ll either need a new in-tank or inline electric pump. To make sure you get the right replacement, take a look at your car manual or simply take note of your vehicle’s old pump type. Replacing an in-tank type assembly is trickier than when replacing an inline type because an in-tank might require you to remove the fuel tank first.
Does my car use a mechanical or electrical pump?
Old cars or antique vehicles that use carburetor-based engines are most likely equipped with a mechanical pump, while modern cars with fuel injection systems rely on an electronic fuel pump. This because a mechanical pump won’t be able to generate the amount of pressure needed by a fuel injection type. So if you have a carburetor-based engine, your pump assembly is most probably a mechanical type. If your car uses a fuel injection system, you’ll need a new electrical pump.
Questions to retailer or dealer:
What other information do I need when looking up a pump assembly?
In some cases, you’ll also need the engine VIN code aside from the vehicle year, make, and model when looking for a new pump. This is especially true on certain applications such as in GM Flex Fuel vehicles.
What other factors should I consider aside from pump assembly type and car specs?
A lot of pump kits look the same on the outside but may actually have different pressure ratings and flow rates. Consult your vehicle manual or a mechanic to determine your old pump’s specs to make sure you get the right part.
How much does a fuel pump cost?
The cost of replacing a fuel pump varies depending on the model and make of your car. OEM replacement fuel pumps typically cost anywhere between $40 to $2,600. Complete fuel pump modules are available, but fuel pump motors and sensors may also be sold individually. It is also recommended to replace your car’s fuel filter whenever the fuel pump is replaced.
While it is possible to install this part on your own, we strongly recommend going to a trusted mechanic. Extreme caution is needed when replacing a fuel pump. Due to its location inside or near the gas tank, there is a risk of igniting fuel. Accidental dumping of gas into organic material also poses health and environmental risks.
How to Install Your Fuel Pump Replacement
A bad fuel pump will starve your engine of fuel and will make starting it extremely difficult. This is why you must immediately replace a busted fuel pump.
Here are the steps to follow and tools to use to replace your old fuel pump.
Tools that you'll need:
- Socket wrench set
- Open end wrench set
- Philips head screwdriver
- Flat head screwdriver
- Fuel container
- Fire Extinguisher
Work in a well-ventilated area and be sure to have a fire extinguisher close by.
You will deal with several screws and bolts in this project. Set them aside in a safe place while working. You wouldn't want to lose any of them.
Make sure that the problem is indeed the fuel pump and not some other part, such as the fuel pump fuse, the fuel filter, or the fuel lines.
The following steps are for electronic fuel pumps only.
Step 1: Release the pressure from the fuel lines. Find the relay or fuse that controls the fuel pump. Start the engine and remove the fuse or relay. The engine will quickly die after it has used up all of the pressurized fuel still in the lines. Disconnect the negative battery terminal after the engine dies.
Step 2: There are two types of electric fuel pump setups, namely, the under-the-car setup and the in-tank setup. If your pump is under the car, go to step 3A. If it is the in-tank variety, go to step 3B.
Step 3A: Raise the car and secure it using jack stands. Slide underneath and follow the fuel lines toward the fuel tank. The pump should be somewhere in front of the tank. Unbolt the pump and let it drop slightly.
Step 3B: Look for the access point to the fuel pump either underneath your backseat or under the carpet in your trunk. Pop it open to reveal the pump.
Step 4: Disconnect the fuel lines from the fuel pump. Make sure you have a pan or container to catch any fuel that may still be in the fuel lines. Once disconnected, gently remove the pump and move it away.
Step 5: Install the new pump. Reconnect the fuel lines and put everything else back in place in reverse order.
Once you've put everything back in place, fill up the gas tank and start the engine to test the new pump.