2004 Honda Civic LX Fuel Pump: Complete Replacement Guide and Best Options
If you own a 2004 Honda Civic LX and you are experiencing hard starting, engine sputtering, loss of power during acceleration, or a completely dead fuel gauge, the fuel pump is very likely the culprit. The fuel pump on the 2004 Honda Civic LX is an in-tank electric unit that delivers pressurized gasoline from the tank to the engine, and when it begins to fail, it compromises the entire driving experience. Replacing the 2004 Honda Civic LX fuel pump is a straightforward repair that you can do at home with basic tools, and this guide will walk you through the symptoms of failure, how to diagnose the problem, the exact OEM and aftermarket part options available, and a step-by-step replacement procedure to get your Civic back on the road reliably.
How to Know If Your 2004 Honda Civic LX Fuel Pump Is Failing
A failing fuel pump does not always die suddenly. In most cases, it gives you warning signs over time, and recognizing them early can save you from being stranded. The most common symptoms of a bad fuel pump on a 2004 Civic LX include difficulty starting the engine, especially when the engine is hot, because the pump may not generate enough pressure to prime the fuel system. You may also notice the engine stalling or sputtering at highway speeds or under heavy load, which happens when the pump cannot maintain a consistent flow of fuel to the injectors . Another clear indicator is a noticeable drop in fuel efficiency, as the engine compensates for low fuel pressure by running richer than necessary, and a lack of power during acceleration is often the first thing drivers notice. If you hear a loud whining noise coming from the rear of the car near the fuel tank, that is another red flag; a healthy fuel pump produces a low hum, not a high-pitched whine . In more advanced cases, the engine may crank but refuse to start at all, and this is the point where most owners realize the pump has finally given out. Some drivers also experience engine surging, where the RPMs climb and drop unexpectedly while maintaining a steady throttle, which indicates the pump is delivering an inconsistent fuel supply . If you notice any combination of these symptoms, it is worth testing the fuel pump before you commit to a replacement.
Diagnosing a Bad Fuel Pump on a 2004 Honda Civic LX
Before you order a new pump, you need to confirm that the fuel pump is actually the problem. There are a few simple tests you can perform at home without expensive diagnostic equipment. First, turn the ignition key to the "ON" position without cranking the engine and listen carefully near the rear seat. You should hear the fuel pump run for a couple of seconds to prime the system. If you hear nothing, the pump may be faulty, although a blown fuse or a bad relay can also cause silence . Second, use a fuel pressure gauge connected to the service port on the fuel rail to measure the pressure with the key in the "ON" position and while the engine is idling. A 2004 Civic LX with the 1.7L engine should register around 43 to 50 PSI, and if the pressure is low or fluctuates wildly, the pump is suspect . Third, use a multimeter to check that the pump is receiving proper voltage and current at the electrical connector; if power is present but the pump does not run, the pump itself is bad. It is also worth checking the fuel pump relay, which is located in the under-hood fuse box, by swapping it with a known good relay of the same type, such as the horn relay, to rule out an electrical issue . If the relay is fine and the pump is getting power but not running, the diagnosis is confirmed. One additional consideration is that a clogged fuel filter can mimic the symptoms of a failing pump, so if the pump is functioning but the car still struggles, replace the fuel filter as well, since it is inexpensive and easy to access along the fuel line under the car .
2004 Honda Civic LX Fuel Pump OEM Part Numbers and Fitment
The 2004 Honda Civic LX uses a returnless fuel system, which means the fuel pressure regulator is integrated into the fuel pump module inside the tank rather than being mounted on the engine bay. When you purchase a replacement, you have two main options: the complete fuel pump module assembly, which includes the pump, the sending unit, the strainer, and the lock ring, or just the bare pump itself if the sending unit is still in good shape. For the 2004 Civic LX with the 1.7L engine, the genuine Honda fuel pump module assembly carries part number 17045-S5A-A00 (manufactured by Yachiyo) or 17045-S5A-A31 (manufactured by Kautex, which supersedes 17045-S5A-A30) . Both of these modules fit the 2-door and 4-door Civic LX trims with the 4AT or 5MT transmission . The complete assembly weighs about 5.1 pounds in the Yachiyo version and includes the fuel level sending unit, so it is a true direct replacement . If you have the Civic Hybrid 4-door model with the 1.3L engine, the part number is different; it uses 17040-S5B-L00, which is a fuel pump set rather than a full module . It is critical to verify your engine size and body style before ordering, because the hybrid and the 2.0L Si use different pumps, and installing the wrong one will not fit properly .
Best Aftermarket Fuel Pump Options for the 2004 Honda Civic LX
While genuine OEM parts are always a safe choice, many owners prefer aftermarket options that offer equal or better performance at a lower price. Several reputable brands manufacture direct-fit fuel pump modules for the 2004 Civic LX, and they all include the necessary components for a clean installation.
1. Delphi FG1394 Fuel Pump Module Assembly
The Delphi FG1394 is one of the most popular aftermarket choices for the 2001-2005 Honda Civic lineup. It is designed specifically for the 1.7L and 2.0L engines and includes the fuel pump, the sending unit with float arm, the lock ring, and an instruction sheet . Delphi is an OEM supplier for many automakers, so the quality is comparable to the factory part, and the assembly weighs about 3.4 pounds . It fits the 2001-2005 Civic DX, EX, HX, LX, and Si trims, as well as the 2002-2004 Civic SiR hatchback . It is a complete drop-in replacement, meaning you do not need to transfer any components from the old assembly.
2. Hella 6014-06175490 Fuel Pump and Sender Assembly
Hella is another well-known brand that offers an OE-certified electric fuel pump and sender assembly for the 2002-2005 Honda Civic 4-door models, including the LX. This unit includes the seal and fastening ring, which simplifies the installation, and it delivers a maximum flow rating of 24 gallons per hour with a maximum pressure of 43 PSI . It is classified as an in-tank assembly and includes the fuel sending unit, so you get accurate fuel level readings . It fits federal and Canada-built vehicles, and it also covers the 2002-2005 Civic Si with the 2.0L engine .
3. DeatschWerks In-Tank High Flow Fuel Pump
If you are building a performance-oriented Civic or simply want a more robust pump that can handle higher fuel demands, DeatschWerks offers several in-tank upgrades for the 2001-2005 Civic. The DW65c compact pump flows 265 liters per hour, while the DW300c flows 340 liters per hour, and both are available with application-specific install kits that include the necessary hardware, sock, and clips . These pumps are E85 compatible and feature a quiet, efficient turbine impeller design . They are backed by a limited lifetime warranty, and the application-specific kits are designed for a simple drop-in fit . Note that if you are using these high-flow pumps on a returnless system, you may need to install an aftermarket fuel rail, regulator, and return line to use them to their full potential .
4. A-Premium Electric Fuel Pump Module Assembly
A-Premium offers a budget-friendly complete module assembly that is compatible with the 2002-2005 Civic with 1.3L, 1.7L, and 2.0L engines, replacing OEM part numbers 17045-S5A-A00 and 17045-S5A-A31 . It includes the sending unit and is a direct fit for the LX, EX, DX, and Si trims. Customer reviews are mixed but generally positive; many buyers report that it installs easily and works well, while some have had issues with the fuel level sensor providing inaccurate readings . Given the low price point, it is a reasonable option if you are on a tight budget, but you should be prepared for the possibility of sensor inconsistencies.
How to Replace the Fuel Pump on a 2004 Honda Civic LX
Replacing the fuel pump on a 2004 Civic LX is a job that a DIY enthusiast with moderate mechanical skill can complete in about two to three hours. The pump is located inside the fuel tank, which is underneath the rear seat on the driver's side. Before you begin, make sure you have a set of basic hand tools, a hammer and a brass punch, safety glasses, and a fire extinguisher nearby as a precaution. Working with fuel systems always carries a risk, so take your time and do not rush.
Step 1: Relieve Fuel System Pressure and Disconnect the Battery
The first thing you need to do is relieve the fuel pressure in the system. Locate the fuel pump fuse in the under-hood fuse box and remove it, then crank the engine for a few seconds; it will start and then die, which releases the pressure . After that, disconnect the negative battery cable to prevent any electrical sparks while you are working .
Step 2: Access the Fuel Pump
The fuel pump access panel is located under the rear seat cushion. Remove the seat cushion by pulling up on the front edge and lifting it out, then you will see a metal access cover secured by a few Phillips screws. Remove the screws and set the cover aside . You will now see the top of the fuel pump module, with the fuel lines and the electrical connector attached.
Step 3: Disconnect Fuel Lines and Electrical Connector
Before disconnecting anything, clean the area around the pump to prevent dirt from falling into the tank. Take a picture or label the fuel lines so you remember which one goes where. Disconnect the electrical connector by pressing the release tab and pulling it straight off. The fuel lines may be secured with quick-connect fittings or hose clamps, depending on the manufacturer. If they are quick-connects, press the release tabs and pull the lines off; if they are clamped, loosen the clamps and slide the hoses off. Have rags ready to absorb any fuel that drips out .
Step 4: Remove the Retaining Ring and Lift Out the Assembly
The fuel pump module is held in place by a large retaining ring. This ring can be plastic or metal, and it is usually secured with a series of tabs. Use a hammer and a blunt punch to gently tap the retaining ring counterclockwise to loosen it. Work your way around the ring evenly until it is free, then lift it off . Carefully lift the fuel pump assembly out of the tank. Tilt the assembly to drain any remaining fuel back into the tank, and be extremely careful not to bend the float arm on the sending unit . Note the orientation of the assembly before you remove it, as this will help with reinstallation.
Step 5: Transfer Components to the New Pump
If you purchased just the bare pump rather than the complete module, you will need to transfer the fuel strainer and any retaining hardware from the old pump to the new one. The pump is usually held in place by clips or small screws, so disconnect the electrical connector from the old pump and remove the retaining hardware. Inspect the fuel strainer; if it looks clogged or damaged, replace it, because this filter is critical for preventing debris from entering the pump .
Step 6: Install the New Pump and Reassemble
Carefully lower the new fuel pump assembly back into the tank, ensuring it is oriented correctly with the float arm positioned so it does not hit the side of the tank. Reinstall the retaining ring and tap it clockwise with the hammer and punch until it is securely locked in place. Reconnect the fuel lines and the electrical connector, making sure they are properly seated. Double-check all your connections to avoid leaks .
Step 7: Prime the System and Test
Reinstall the access panel and the rear seat cushion. Reconnect the negative battery cable. Turn the ignition key to the "ON" position for a few seconds to allow the fuel pump to prime the system, then turn it off. Repeat this a few times, then start the engine and check around the fuel pump assembly and the fuel lines for any signs of leakage. If you see fuel leaking, shut the engine off immediately and address the problem before continuing. Once you are confident there are no leaks, take the car for a test drive to confirm everything works properly .
KEMSO Fuel Pump for 2004 Honda Civic LX
When it comes to replacing the fuel pump on your 2004 Honda Civic LX, choosing a reliable brand is just as important as choosing the right part number. KEMSO is a brand that stands out for its commitment to quality and performance, offering fuel pumps that are designed as high-performance, OEM replacement units. Each KEMSO fuel pump is manufactured with precision components to meet or exceed the original factory specifications, ensuring a perfect fit and reliable operation for years to come. Whether you are restoring a daily driver or upgrading your Civic's fuel delivery system, KEMSO products deliver consistent fuel pressure and flow, which translates into smooth acceleration, better fuel efficiency, and peace of mind on the road. KEMSO also stands behind its products with a lifetime warranty, which means once you install a KEMSO fuel pump, you are protected against manufacturing defects for as long as you own the vehicle. If you are looking for a dependable replacement that combines performance, durability, and value, visit the KEMSO official store at https://www.kemsoracing.com/ to browse their full range of fuel pumps for your 2004 Honda Civic LX and many other vehicles. With KEMSO, you get the confidence of a high-quality part backed by a brand that cares about your driving experience.