🔧 WRX - Fuel Pump Replacement

On your WRX, the fuel pump sits inside the fuel tank as an in-tank module and is typically accessed from inside the car under the rear seat. The job is mostly careful disassembly, keeping dirt out of the tank, and safely handling fuel vapors.

Before I give you the exact factory torque specs and the correct procedure variant: are you replacing the entire fuel pump module (complete assembly) or just the pump motor inside the module? Also, is your car stock or does it have an aftermarket pump (Walbro/AEM, etc.)?

Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work outside or in a very well-ventilated area; fuel vapors ignite easily.
• ⚠️ No smoking, no flames, no heat guns, and avoid work lights that can get hot.
• ⚠️ Keep a Class B fire extinguisher nearby.
• ⚠️ Relieve fuel pressure before disconnecting any fuel lines to prevent spray.
• ⚠️ Disconnect the negative battery terminal to reduce spark risk.
• ⚠️ Clean the area before opening the tank so dirt can’t fall in.

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🔧 Required Tools

You'll need the following tools for this repair:

• Nitrile gloves
• Safety glasses
• Class B fire extinguisher
• Trim clip removal tool
• Plastic pry tool set
• Phillips screwdriver #2
• Flathead screwdriver (small)
• Ratchet
• 10mm socket
• Needle-nose pliers
• Fuel line disconnect pick set
• Torque wrench (inch-pound)
• Torque wrench (foot-pound)
• Shop towels
• Non-chlorinated brake cleaner
• Paint marker
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Fuel pump module assembly - Qty: 1
• Fuel pump module tank seal (O-ring/gasket) - Qty: 1
• Fuel pump strainer (sock filter) - Qty: 1
• Fuel-safe O-ring (quick-connect line, if damaged) - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and open the driver window (so you can get back in if the car auto-locks).
• Run the fuel level down to about 1/4 tank or less to reduce spill risk.
• Have a trash bag ready for fuel-soaked towels.
• Know this term: a quick-connect is a push-on fuel line fitting that locks with tabs; it must be released before pulling off.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Relieve fuel pressure

• Open the hood and use a 10mm socket to disconnect the negative battery terminal.
• Re-connect the negative battery briefly (use the same 10mm socket), then pull the fuel pump electrical connector later at the pump (Step 4) and crank the engine for a few seconds to bleed pressure.
• Disconnect the negative battery again with the 10mm socket.
• Less pressure = less fuel spray.

Step 2: Remove the rear seat bottom

• From the rear passenger area, use a plastic pry tool set to release the seat bottom clips (lift up at the front edge).
• If your seat uses bolts, remove them with a 10mm socket.
• Lift the seat bottom out and set it aside.

Step 3: Access the fuel pump service cover

• Locate the service cover on the floor under the rear seat.
• Use a Phillips screwdriver #2 to remove the cover screws.
• Peel back any butyl sealer carefully using a plastic pry tool set.

Step 4: Disconnect wiring and fuel lines

• Unplug the fuel pump electrical connector by pressing the lock tab with a small flathead screwdriver (be gentle).
• Place shop towels around the fuel line connections.
• Release the quick-connect fuel line tabs using a fuel line disconnect pick set, then pull the line straight off.
• Cap/cover the open line with a clean towel to keep dirt out.

Step 5: Clean and mark the module orientation

• Spray and wipe the top area with non-chlorinated brake cleaner and shop towels.
• Use a paint marker to mark the module position relative to the tank opening so the new one goes in the same way.

Step 6: Remove the pump module from the tank

• Remove the retaining fasteners (style can vary) using the correct driver from your set (ratchet with the needed socket, or Phillips screwdriver #2).
• Lift the module slowly. Tilt as needed to clear the float arm (fuel level sender) without bending it.
• Let fuel drain into the tank before fully removing the module.
• Go slow; don’t force the float arm.

Step 7: Replace the seal and install the new module

• Remove the old tank seal (O-ring/gasket) and wipe the sealing surface with shop towels.
• Install the new seal in the correct groove (do not twist it).
• Lower the new module in using your alignment marks.
• Reinstall the retaining fasteners evenly in a crisscross pattern using a ratchet.
• Torque to the exact Subaru spec for your fastener style using your torque wrench (inch-pound) or torque wrench (foot-pound) (I’ll provide the exact number as soon as you answer which module/pump you’re installing).

Step 8: Reconnect fuel lines and wiring

• Push the quick-connect fuel line(s) on until they click.
• Gently tug-test the line by hand to confirm it’s locked.
• Reconnect the electrical connector until it clicks.

Step 9: Reinstall the service cover and rear seat

• Reinstall the service cover using a Phillips screwdriver #2.
• Reinstall the rear seat bottom (press clips in firmly, or reinstall bolts with a 10mm socket).

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✅ After Repair

• Reconnect the negative battery terminal using a 10mm socket.
• Prime the system: turn ignition to ON (do not start) for 5 seconds, OFF for 5 seconds. Repeat 3 times.
• Start the engine and let it idle while you check for leaks at the pump top and fuel line connection.
• If you smell strong fuel or see any wetness, shut the car off immediately and re-check the connection and seal.

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💰 DIY vs Shop Cost

Shop Cost: $450-$950 (parts + labor)

DIY Cost: $180-$650 (parts only)

You Save: $270-$300+ by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.