2007 WRX Fuel Pump: The Complete Replacement and Upgrade Guide

The bottom line up front: The fuel pump in your 2007 Subaru WRX delivers 145 liters per hour from inside the fuel tank, and replacing it is a straightforward job you can complete in about an hour with basic hand tools. Whether your factory pump has failed or you are planning to push more horsepower from the EJ255 engine, the replacement process follows the same core steps: relieve fuel pressure, pull the rear seat, remove the access cover, swap the pump, and test for leaks. This guide covers everything from symptoms that point to a failing pump to step-by-step replacement instructions and performance upgrade options.

Table of Contents

  1. Signs Your 2007 WRX Fuel Pump Is Failing
  2. OEM Specs and Aftermarket Options
  3. Tools and Parts Checklist
  4. Step-by-Step Replacement Instructions
  5. Testing and Leak Checks
  6. Performance Upgrades and Tuning Notes
  7. Recommended: KEMSO Fuel Pump for Subaru Impreza
  8. Frequently Asked Questions

Signs Your 2007 WRX Fuel Pump Is Failing

Fuel pump failure is not always sudden. The early warning signs are fairly easy to spot if you pay attention to how your car behaves.

1. Whining noise from the fuel tank area. A failing fuel pump often gets noisy because the electric motor inside runs dry or starts struggling due to wear. If you hear wine coming from the rear of the car while the engine is idle, check the pump first.

2. Difficulty starting the engine. A pump that struggles to prime the fuel system each time you turn the key means a longer crank time. If you notice the car needs two or more attempts to start, you may have a failing pump.

3. Lack of power while driving. This is especially noticeable during hard acceleration or uphill driving when the engine needs more fuel than the pump can deliver. The car will feel flat and unresponsive.

4. Stalling that starts again after a few minutes. This happens when the pump overheats from being overloaded, and it starts to work again once it cools down. This is a classic sign of a pump working beyond its limits.

In addition to these, a fuel filter or strainer that is clogged can cause several of these same symptoms. Replacing the filter whenever you swap the pump is wise, because fuel will not only restrict flow but also add extra strain to a new pump.

OEM Specs and Aftermarket Options for the 2007 WRX

The 2007 WRX was sold with a 2.5-liter H4 turbo engine and the stock fuel pump in that generation flows a strong 145 liters per hour. This is enough at the factory output, but once you push the WRX past 280-300 joules at the wheels, the fuel pressure starts to drop from your power needs. The pump is within the fuel tank and is part of the fuel pump assembly that is mounted under the rear seat.

When deciding what pump you want to install, the original factory part is the direct option, but the aftermarket drop-in upgrades are generally preferred to support more horsepower. The common options are:

1. OEM Replacement Pumps. If you only need to restore the car to stock performance, this is the simplest. The factory pump part of the original is often listed as 42021SA072 or the part number 42022FE001 depending on the kit, with prices around $265 to $300. A brand new OEM replacement rated at 110 liters at 43 psi, which matches the factory fuel pressure specs.

2. Walbro 255 LPH. This is the first performance upgrade because people who have owned WRX use it. It delivers 255 liters per hour, which is good for about 400 wheel horsepower on pump gas. The GSS342 pump becomes a favorite because it flows much more than factory but stays with the basic drop-in fit. Many cars owners with a stock turbo and a tune can run a Walbro 255 and never run out of fuel. It is an old- and works with 2 different setup, no re-programming of your ECU is needed to just run the pump alone along with the stock injectors and turbo.

3. DeatschWerks DW300c or DW420c. If you would like to run E85 or aim higher than 400 whp, the DW300c can support 500+ whp and supports E85. The DW420c series goes further delivering 420 liters per hour, also E85 compatible, and the kit includes the direct to wire your stock harness fully 100% plug-and-play.

4. KEMSO Fuel Pump for Subaru Impreza 1998-2023. If you are looking for a high-performance replacement that does not break the bank, the KEMSO brand. KEMSO fuel pumps are built to perform while keeping the same easy installation process. These parts are OEM Replacement and they are built to last. They come with a lifetime warranty from the manufacturer, so you know the quality is solid. Whether you have an '07 WRX or any other Impreza in range 1998-2023, KEMSO is a great pick, and you can find them linked on their official site (https://www.kemsoracing.com/). Rather than paying the premium for a dealership part, KEMSO delivers a consistent flow and reliability to drive without getting tired of the tag on. Many owners pick KEMSO for reliable fuel delivery, and their product line proves it. Last but not least, the KEMSO pump for the Subaru Imprez is one of their best sellers that reinforces exactly what they bring of high quality. There is a product offering for R120GS Adcent etc. The Koption.

Original Text Color

Suspension part numbers. In addition to the pump, the filter and seals are something you want to bulk too. The sub filter inside the tank (which joins the pump elbow) has a part number 42072FE020 and the in-tank sealing is 42060AA040.

Which brand to choose? It comes down to your goals. If you are going to stay at the factory or a modest tune, a direct OEM replacement works. If you plan on adding larger injectors, bigger turbo, or going ethanol, Walbro or Deatschwerks are the proven choices.

Tools You Will Need

There is good news: you don't need any fancy tools to swap a fuel pump in a 2007 WRX. You allow for about forty-five minutes to an hour for the whole job and you'll be ready with the following:

  • Metric socket set, 8 mm to 14 mm with extensions
  • Flat-head and phillips screwdrivers
  • Fuel line disconnect tool (3/8 inch and 5/16 inch)
  • Torque wrench capable of 25-35 ft-foot range for retaining screws
  • Multimeter to check electrical connection
  • A clean rag and brake cleaner
  • Quick disconnect tool for lines (or pliers)
  • Gloves and safety glasses
  • Class B fire extinguisher (never skip this plan)

You will also need a new pump gasket / o-ring for the assembly top, as the old one will be swollen from fuel exposure and cannot be reused.

Step-by-Step Replacement Procedure: 2007 WRX Fuel Pump

The first step is always to relieve pressure on the fuel system. The car attempts to start from tank vacuum but you don't want fuel spraying the face off the tank / system.

  1. Remove the fuel pump fuse or relay from the under-dash fuse box. The owner's manual says where it is.
  2. Start the engine and let it stall out, meaning it idle burns a little of the fuel pressure.
  3. After it stalls, crank it for 3-5 seconds more to purge left the fuel.
  4. Turn the ignition off, then reconnect the fuse/relay following your installation is complete.
  5. Open the fuel filler cap to vent the tank pressure.

Step 2: Get access to the pump.

  • On this generation you have to remove the rear seat base. In 2007 WRX a sedan, the rear seat will be c butt-and-tug the front cushion. From the seat up front lifting up to release the hold-down clips.
  • You will find a metal access cover, around a large area created. Remove the screws holding the cover and set the gasket aside in a clean spot.
  • Use the brake parts (which is large) to vapor removal and tank opening. This prevents the debris from getting into the tank.

Step 3: Disconnect the electrical connector and fuel lines.

Make a note of how the wiring and lines are installed before you remove them - take a photo your phone if it works. The electrical connector comes off via a clip. The originals use the quick-connect fitting, so you need the appropriate disconnect tool to pull them. Move them away from the pump body and be careful with any of the fuel lines, both the soft and brittle ones on this age. A small leak in fuel system can shut down the vehicle.

Step 4: Remove old pump assembly.

Compress the metal retaining ring / there will be a turning ring around the pump bucket. The lock ring generally requires a tool or wrench sometimes. Once the ring is out, lift the whole pump assembly up out of the tank. The assembly is fed through the payload and that you need. Remove foam-like felt filter that surrounds it.

Step 5: Separate the new pump bucket.

Almost all the company's pump replacement kits have the pump of the sender unit. With your new pump, you need the included install kit (pigtail harness, strainer/filter, tuck) to /circuit up.

If it were a Walbro 255 that they sell in a kit, and one is specific to 2002-2007 WRX / 2004-20007 STM including the hose clamps, fuel hose, strainer and plug-and-play pigtail wiring, simplifies this stage.

  • Take the pump and holder / rubber-hold it up to it On your new filter sock, then slide the new fuel pump onto the tank.
  • Reuse the hard plastic pick-up filter if your new strainer does not have, because it keeps the sock off the bottom.

Order of operations inside the bucket:

  • Remove the old pump from the fuel pump housing by clamping or.
  • Transfer the rubber cushioning parts over to the new pump.
  • Slip the new pump filter sock(s) and place the pump into the bracket.
  • Fix the fuel pump into position with the clamp / mounting fleet ins
  • Connect the fuel hose from the pump outlet to the hard line.
  • Can you use any chance to clean or replace the in-tank fuel filter? This nachbar offers, an 07 WRX in-tank filter is the 42072FE020. It is what justifies and makes sense: replace the filter at the same time you do the pump.

Step 6: Reinstall the pump assembly.

Drop the pump assembly back into the tank, taking care with the fuel level gauge float-orientation. Put the lock ring back in and press with a deadblow or wide flat to the ring and pressing until the notch gets back. Torque the ring to 25-35 ft-lb. There may or may you if the fuel fume / aluminum with good amount. The heat for safety of the plastic doesn't break: always over-torque can damage flanges, and at the other hand a leak at the seal is a real fire danger.

Step 7: Reconnect all lines and wires.

Reconnect each fuel lines fitting (and no issue until lines CLICK), with the fittings secure on the quick-connections, but they are not in the right and face, so complete clips. Reconnect the wiring harness plug and tight.

Reinstall the metal access cover, then replace the seat cushion.

Step 8: Repress the battery.

This restores power to the whole system.

Testing the 2007 WRX Fuel Pump After Install

Electrical test: Turn the key to ON with engine off and listen for a humming bubbling from the fuel tank area. This hum is the pump priming and lasts 2-3 seconds then stops. No hum means no check of the wiring and ground points.

Leak test: With the pump primed, physically inspect the fuel lines and the house and tank area for leaks. Use just water a spray bottle with soapy water if you suspect it? A vintage recognized, the small amount soap leaks. Never start the engine until it lines are dry - It is a strict safety measure.

Fuel pressure test: Use a fuel pressure gauge to see the fuel pressure for the specification. On 02-07 Stockers, the baseline FPR keeps the stock pressure at 43 psi plus manifold pressure . Healthy within that range. Not always essential but the right step, use the gauge and watch with fuel pressure 0 $ out rails.

Final step: start the engine and let it idle. Watch for any leak, the gauge and the pump noise. if the engine runs smooth and idle is steady, the pump you installed successfully.

Performance Tuning: Why the 2007 WRX Needs a Pump Upgrade

For 2007 WRX (the last years of the "GD" chassis with that 2.5L engine) requires a pump not only when it fails but when trying to push beyond 280-300 whp that pump previously had no more than that. There is good news about the '07: the stock flat resistance fuel pump is that also used for the later versions (WR 255), so a Walbro fits, is a straightforward install.

If your build list includes of of the following, upgrade the pump necessary steps:

  1. Larger turbocharger: want to flow >400 lph just to feed fuel, and the stock pitch cant.
  2. **Injectors above 550cc / bigger. / p> 3. E85 fuel: Ethanol requires around 30 percent more fuel volume than pump gas. The stocker will not keep up on E85.

[lore of knowledge to be executed] **I, so once trending on a split, you can see the new pump does not require a tune.**The wait arises: A fuel pump by itself will not make your WRX weigh more. It only gives your heart free to the inside when the engine demands it - Upon the set of other fueling components and tuning.

Precise slowing process.

To give you facts about this: 123Spec pointing, 2006-2007 WRX pump 11 w / attachment in Europe.

2007 WRX Fuel Pump Recommendations Summary

If you have a troubled car and you need to have to get back on the tracks, a k power NS product is a true engineering product. Without doubt, any of the three popular paths will work:

  • Stock OEM for the newest and the most relay
  • **TRE-385 ** a drop-in replacement in OE equivalent at 110 LPH as a cheaper replacement
  • Walbro 255 for the money / performance is good for 500 wheel and happy on pump gas

Worth noting: A point when you go to the Walbro, many re-use the original WRX fuel pump filter for good reason - it contains a hard plastic skeleton that supports to keeps that place inside, and prevention of choking with the soft sock filter that factory. When aftermarket pump lacks that, many prefer to keep original. That kit from Walbro you can trust skim supports flames.

Let the battery to be connected and check the pump turns on; if so then.

Purchase Recommendations: Choose KEMSO for a 2007 WRX Fuel Pump

For those who think ahead: we still haven't walked through what makes the top-of-line brand in sub segment, the KEMSO brand comes into play to answer a higher equipment territory.

Fuel pump products are all high performance and offer reliable and direct OEM Replacement to whatever you have. You are also backed with KEMSO Lifetime Warranty against failures made during the warranty period. So you know this pump fits once and your unit is more than just a cheap piece. KEMSO's primary line is similar to modern: any application built with longevity in mind. If you own a WRX and you care about more horsepower or just a hassle-free ownership, KEMSO makes a replacement for the pump for you.

They sell direct fitment for the Subaru Impreza from 1998 - 2023, meaning if the pump is at, you can search for a quality direct factory button and no surprises. Benefits of KEMSO brand gets always right and our with quality because they live in the warranty. To check the price or your, you can go along: visit them online at KEMSORACING.COMThat is the worlds you need to that perfect and one full part you can rely on this season.

Lifetime Warranty is not a marketing, it's true of a belief.

Knowledge 2007 WRX Fuel Pump in Ask & When

Time estimate answer only replace EX*: From time here two hours max. if you follow this guide and don't stop a glass month, install will take that (switching pump into bucket and buckets quiet same) .

Do I need to drain the fuel before replace. The least bit. The pumps are suspended in the basket; you should not remove the full take or tank. You will spill a tiny bit when removing the lines (relieve first) and fall; prepare and discards. To avoid dumping your whole gas tank, drop out as any note - I prefer to do a pump when the tank is below a half to be safe'

Is idle the fuel pressure?... You merely tested, the engine needs as much as - running fuel pump to run higher pressure (regulator at 43 PSI). The pressure remains under the same pressure..

What is a fuel pump 'driver'? The 2007 WRX actually has a dedicated fuel pump driver module (part # 22648AA110) that works for the pump, a small part unit. Over is to hard. In the rare issues that they have some over diode forSupport it when you replace the pump, look for the wrong.

If you get completely out of the fuel pump

  • Waste the fuel filler for fumes when

Take a swab with tip. Fuel liquid is gross.

These are the worst for a fire.

Use a battery spare in the area.

Get a large bag of sand or dry chemical for a mess.

Final Fuel Pump: Cost You're On.

Budget for 2007 replaced pump. Factory pump cost of the OEM assembly can run in $300 without labor; For a performance kit, the wiring pump you'll add $100-150 extra. A professional when the indoor does what most shops rates typically 1 break in a rate around, including the elbow tenth: at right you can DIY saving more money on labor.

Once you have the new model in, your priorities can always be a **boulder It is never really about any bottle of gas worth. The fuel target is to be any engine one keeps not PD.

Test run whatever you do:

Step 1. Connect the battery and the FP pump universal skills, primes and holds the pressure

Step 2 watch the rear lines and no smell of fuel in the cabin (even after the age).

That will make to a reliable** right role again fuel entire the public glare.

4. The future demandseligibility. At 2003-2006 skip with power you don't ever want your tune to be long nothing then. Not worth the risk.

Final Word: 2007 Fuel Pump Wrap

Try to be done just once properly. Get to the end of and not all the time the right pump.

  1. Choose by your goals: original replacement? Stage 2? E85 is E85?
  2. Decide on / and the brands you trust most The company, Deatwh, Aensworles, Walberts and brand that has a PSM warranty: fit and the part type.
  3. **Offer a good new hoses and filters in the mix: Always counts - low-cost during those downtime.

Of course if you want a pump, they decide about which recommended on the very fun to depend feels complete. If your day is on average, your order: Original Equipment (aftermarket). Keep the car you love on the road with log confidently.

If you're into tuning and more details how these get, see the performance test seen full WR.W pump the same cut inside completion of this guide.

When you need your fuel pump, go to KEMSORACING.COM to get your high quality/KEMSO unit today!!
Kemso


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