Pushing a 2G Eclipse past the 350-horsepower mark demands a fuel system that can deliver consistent, high-volume flow under load. Stock fuel pumps quickly run out of capacity at these power levels, leading to lean conditions that risk engine damage. The Aeromotive 340 LPH Stealth Fuel Pump (often referred to as the “A1000” for larger builds, but the 340 is ideal for 350-550 hp) offers a proven, budget-friendly solution. At roughly $200, it provides the flow headroom needed for turbo upgrades, larger injectors, and tuning on gasoline or E85 without requiring a full surge-tank setup. This guide walks through the installation process, covering preparation, tooling, step-by-step replacement, and post-installation checks to ensure a safe, reliable upgrade.

Why the Aeromotive 340 LPH Pump for a 2G Eclipse?

The 2G DSM fuel system is a return-style design, meaning the pump pushes fuel through the rail and a regulator returns excess to the tank. The Aeromotive 340 pump is a direct-fit drop-in replacement for the factory unit, but its construction and flow characteristics are far superior. Here is what makes it a strong choice:

  • High-Flow Capacity: At 13.5 volts and 43 psi, it flows roughly 340 liters per hour—enough to support 550+ hp on gasoline and around 450 hp on E85 when paired with an adjustable fuel pressure regulator (AFPR).
  • Continuous-Duty Reliability: The pump uses a hardened commutator and carbon brushes designed for long-term operation. Many DSM owners report tens of thousands of miles without failure.
  • E85 Compatibility: The pump’s internal components resist ethanol corrosion, making it a viable upgrade for flex-fuel or dedicated E85 builds.
  • Affordable Entry Point: Priced around $200 (versus $400+ for OEM replacement or larger brushless pumps), it offers an excellent cost-per-horsepower ratio.

A common question is whether the pump is “too much” for a street car. Because it’s a positive-displacement gear-type pump (not a noisy gerotor), it runs quietly—much quieter than the stock pump at idle—and its size does not interfere with the factory basket assembly.

Tools, Materials, and Safety Preparations

Before you start, gather the following items. Having everything on hand prevents mid-job trips to the auto parts store.

Essential Tools

  • 5 mm, 6 mm, and 10 mm hex sockets with a ratchet and extensions
  • flat-blade screwdriver (for prying the access cover)
  • slip-joint pliers or a fuel line disconnect tool
  • wire cutters, strippers, and a crimping tool – do not rely on twist-and-tape connections for fuel pump power
  • small pick set for removing o-rings
  • shop rags and a fire extinguisher (rated for fuel)
  • digital multimeter to verify voltage at the pump

Parts and Consumables

  • Aeromotive 340 LPH fuel pump (P/N 11142 for the standard drop-in, or 11140 for the “Stealth” model with a separate inlet filter)
  • Fuel pump rewire relay kit (recommended; e.g., STM or Jester’s kit) – this restores full voltage to the pump by running a dedicated 12V line from the battery
  • 5/16” fuel injection hose (about 2 feet) and EFI-approved clamps if you are replacing the internal hose
  • New fuel tank access cover gasket (part number MR188599 or generic foam sheet)
  • Flexible fuel hose for the rewire harness (if not included in kit)
  • Thread sealant or PTFE tape for any AN fittings (if you are also adding an AFPR)

Critical Safety Steps

Work outdoors or in a well-ventilated space. Gasoline vapors are explosive. Before opening the tank:

  1. Disconnect the negative battery terminal (use a memory saver if you need to keep radio presets).
  2. Relieve fuel pressure by pulling the fuel pump relay (inside the engine bay fuse box) and cranking the engine for a few seconds until it stalls. Crank again for 2 seconds to confirm zero pressure.
  3. Place rags around the access cover to catch any drips.

Step-by-Step Installation

1. Accessing the Fuel Pump Mounting Plate

The fuel pump sits under the rear seat on the passenger side of a 2G Eclipse. Lift the rear seat cushion by pulling up firmly at the front edge. Underneath is a black plastic access cover held by four 10 mm bolts (two of which may be hidden under a small plastic plug). Remove the bolts and lift the cover. You will now see the circular metal retaining ring holding the pump module in place.

2. Removing the Old Pump Module

Note: Take pictures of the wiring and hose routing before disassembly – this saves headaches later.

  • Using a large flat blade screwdriver or a special lock-ring tool, tap the retaining ring counterclockwise to loosen it. The ring may be seized; a little penetrating oil helps.
  • Once the ring is free, lift the entire module out of the tank. Be careful with the float arm – it can snap off if bent.
  • Disconnect the two electrical connectors (a large two-pin molex for the pump and a small two-pin for the level sender). Compress the locking tabs and pull gently.
  • Pull the rubber hose from the pump outlet to the module top – it usually slides off with a bit of wiggling.
  • Take the module to a clean workbench. Remove the strainer (sock) from the bottom of the old pump.

3. Swapping the Pump Internal

The Aeromotive 340 pump is slightly taller than the stock pump, but it fits inside the factory plastic basket. If your car has a 2G DSM (1995-1999), the pump sits in a rubber “silencer” sleeve that must be discarded (it does not fit). You will instead use the included rubber mount from Aeromotive or a short piece of 5/8” fuel line wrapped around the pump body for a snug fit. Detailed steps:

  1. Remove the old pump from its cradle by sliding it upward. The outlet nipple will pull out of the rubber jumper hose.
  2. Trim the rubber hose that connects the pump outlet to the module top – reuse the factory spring clamps or replace with EFI worm-gear clamps.
  3. Attach the Aeromotive pump’s outlet to the hose using a clamp. Orient the pump so the wiring pigtail is accessible and the pump body does not touch the tank wall.
  4. Place the pump back into the basket. The bottom of the Aeromotive pump has a fine-mesh inlet screen; do not add the old sock unless it is a high-flow replacement (the Aeromotive screen is adequate for most builds).
  5. Reconnect the wiring: the red wire from the pump goes to the positive (center) pin of the module connector; black goes to the outer (ground) pin. If your rewire kit includes a separate ground, run it through the module to the chassis as well.

4. Reinstalling the Module and Reassembly

  • Gently guide the module back into the tank, making sure the float is free and does not hang.
  • Install the retaining ring by hand then tighten with the lock-ring tool until snug (do not overtighten). Replace the access cover and bolt it down.
  • Reconnect the battery negative.
  • If you are doing a rewire: the relay gets triggered by the factory fuel pump wire (the turquoise wire in the harness near the tank), and the large 12V feed runs from the battery with a fuse. Follow the instructions provided with your kit.

Post-Installation Testing

Before driving, prime the system to check for leaks and confirm pressure.

  1. Turn the ignition to the ON position (do not crank). You should hear the pump whir for 2 seconds – that is the priming cycle. Repeat the ignition cycle 3-4 times to fill the fuel rail.
  2. Check under the rear seat and along the fuel lines for any wet spots. A small pinhole or loose clamp will show up immediately.
  3. Start the engine and let it idle. Use a fuel pressure gauge on the rail (or at the AFPR if you have one) to verify 36-43 psi (depending on your setup). Without an AFPR, the factory regulator will maintain ~43 psi base pressure.
  4. Rev the engine to 3000 rpm and hold – pressure should stay steady within 2 psi. A large drop may indicate a clogged filter or air leak.
  5. Take a short test drive (1-2 miles) under light load. Recheck for leaks afterward.

If the pump sounds louder than expected after installation, check that the rubber isolator is properly positioned. Sometimes the pump resonates against the sheet metal of the tray – a small piece of foam or rubber pad between the pump and the module body can dampen noise.

Additional Considerations for 350+ HP Builds

Fuel Pressure Regulator

The factory fuel pressure regulator works up to about 400 hp on gasoline, but it is calibrated for a return-style system. If you are running larger injectors (e.g., 1000 cc) or E85, an adjustable regulator like the Aeromotive 13201 gives you the ability to set base pressure and maintain fuel pressure under high boost. This is especially important if your pump is at the limit of its voltage (12V vs. 13.5V).

Rewire the Factory Circuit

The stock wiring to the fuel pump is thin (18 or 20 gauge) and runs through many connectors, causing voltage drop. The pump may only see 11.5V at the pump under load, reducing flow significantly. A rewire kit using a relay and 10-gauge wire from the battery restores full voltage. This is a cheap mod (less than $30) and should be considered mandatory for any pump upgrade. Instructions are widely available on DSMTuners.

Upgrade the Fuel Filter

The factory fuel filter is a small in-line unit that can become restrictive at high flow. Replace it with a WIX 33482 or a larger universal filter (e.g., 10-micron, 6AN inlet/outlet) mounted in the engine bay. Change it after the first hour of operation to catch any debris dislodged during installation.

Injector Compatibility

The Aeromotive 340 pump will easily feed 750-1000 cc injectors without starving them. If you are targeting 350-450 hp, 750-850 cc injectors (at 43 psi) are a good match. For E85, step up to 1000-1200 cc to maintain duty cycle. Tuning with ECMLink or a standalone EMS is strongly recommended to calibrate the fuel map and take full advantage of the increased flow.

Common Pitfalls and Troubleshooting

  • Pump won’t prime: Check the rewire connections and the fuse. If the factory wiring is still in use, verify voltage at the pump connector (red wire with ignition ON). A blown factory pump relay can also cause silence – jump the relay socket with a fused jumper wire to test.
  • Low fuel pressure after priming: A loose internal hose or clamp inside the tank is the most likely cause. The jumper hose from the pump outlet to the module top can pop off if not properly secured. Drop the module and inspect.
  • Pump noise enters the cabin: Ensure the pump is not contacting the top of the tank. Use a longer rubber sleeve or add a wrap of heat-shrink tubing to damp vibration.
  • Check engine light: The pump itself will not trigger a CEL, but if you also changed the fuel level sender, the dash gauge may read incorrectly. No DTC will be set for fuel level sender error on most 2G ECUs.

Performance Impact and Dyno Results

With the Aeromotive 340 pump installed and proper tuning, many 2G owners have reported reliable operation at 350-450 wheel horsepower on pump gas. On E85, the same pump can support around 400 whp thanks to the higher fuel volume required. Anecdotally, the pump adds approximately 5-8 horsepower at the wheels simply by eliminating fuel pressure drop at high rpm (where the stock pump would starve the rail). The real benefit is safety – your air/fuel ratio remains stable even during peak boost events. The Aeromotive product page contains a flow curve chart so you can verify your setup’s capacity.

Final Verdict

For under $200 and an afternoon of work, the Aeromotive 340 LPH pump transforms a 2G Eclipse fuel system from a limitation into a foundation for serious power. It installs without modification to the tank or wiring (though a rewire is strongly advised), and its reliability has been proven across thousands of DSM builds. Whether you are aiming for 350 hp on a street-friendly turbo or pushing toward 500 hp with bigger injectors and E85, this pump provides the flow and durability needed to keep the engine safe. Pair it with a fresh filter and a good tune, and you will have a fuel system that never holds you back.