1999 Mitsubishi Eclipse Fuel Pump: Complete Replacement Guide and Best Options

If your 1999 Mitsubishi Eclipse is struggling to start, sputtering during acceleration, or producing a whining noise from the rear of the car, the fuel pump is likely failing and needs to be replaced as soon as possible. The fuel pump on a 1999 Mitsubishi Eclipse is an in-tank electric unit that delivers pressurized fuel from the gas tank to the engine’s fuel injection system. A failing pump can cause a loss of power, engine stalling, poor fuel economy, and eventually leave you stranded. The factory fuel pump output specification is 45 psi, and the fuel system operates on a returnless design with a 14.5-gallon fuel tank capacity . Replacing the pump is a manageable DIY job if you have basic mechanical skills, but choosing the right replacement part is critical to keeping your Eclipse running reliably.

Signs Your 1999 Mitsubishi Eclipse Fuel Pump Is Going Bad

Before you buy a replacement, confirm that the fuel pump is actually the problem. The most common symptoms of a failing fuel pump on a 1999 Eclipse include:

  • Engine cranks but won’t start – This is the most obvious sign. The pump isn’t delivering fuel to the engine .
  • Loss of power under load or uphill – The pump can’t maintain adequate pressure when the engine demands more fuel .
  • Sputtering or hesitation at highway speeds – Inconsistent fuel delivery causes the engine to stumble .
  • Whining or humming noise from the fuel tank area – A healthy pump runs quietly. A loud whine means the pump is wearing out .
  • Engine stalling – The pump may intermittently stop working, causing the engine to die without warning .
  • Check Engine Light – Low fuel pressure or a lean fuel mixture can trigger the light .

If you experience any of these issues, do not ignore them. Driving with a bad fuel pump can cause the engine to run lean, which may damage the catalytic converter or even the engine itself.

Factory OEM Fuel Pump Options for the 1999 Eclipse

The 1999 Mitsubishi Eclipse came with several engine configurations, and the correct fuel pump depends on whether you have a turbocharged or non-turbo model, and whether the car is front-wheel drive or all-wheel drive.

For non-turbo models (2.0L, no turbo, 2WD): The original OEM fuel pump assembly part number is MR134804. This pump is designed for the 2.0L non-turbo Eclipse and comes as a complete assembly . Note that this part has been discontinued and is no longer available for purchase from Mitsubishi . If you find a new old stock unit, it will work, but an aftermarket replacement is often a better choice.

For turbo models (2.0L, with turbo, both FWD and AWD): The OEM fuel pump assembly part number is MR344715. This pump is for the 1995-1999 Eclipse GS-T and GSX models with the turbocharged 4G63 engine. This part has also been discontinued and replaced by MR162453, but that part is also no longer in production .

Because OEM parts are discontinued, most owners turn to high-quality aftermarket pumps that match or exceed factory specifications.

Aftermarket Fuel Pump Options: Which One Should You Choose?

There are several aftermarket fuel pumps that fit the 1999 Mitsubishi Eclipse. The choice depends on whether your car is stock or modified.

1. Standard Replacement Pumps (Stock Engines)

If your 1999 Eclipse is completely stock and you just want a reliable replacement, there are several options:

  • TRQ FPA62082 – This is an in-tank electric fuel pump designed for the 2.4L engine. It has a maximum pressure of 125 PSI, an average flow rating of 26 GPH, and includes a gasket or seal. It costs around $47.95 and comes with a limited lifetime warranty .
  • Hella 358300121 – An in-tank assembly with gaskets and seals, priced around $68.43. Hella is a reputable German brand known for quality electrical components .
  • Hitachi FUP3362 – A direct replacement for 1995-1999 models, priced around $90.93. Hitachi is an OEM supplier for many Japanese vehicles .

2. High-Performance Pumps for Modified Engines

If your Eclipse has a turbo upgrade, larger injectors, or you plan to add nitrous or a supercharger, you need a higher-flow fuel pump.

  • Walbro 255 LPH High-Pressure Pump (GSS342) – This is the most popular upgrade for the 1995-1999 Eclipse turbo models. It flows 255 liters per hour, which is enough to support up to approximately 600 horsepower. The Walbro 255 LPH-HP comes with an install kit that includes a filter, clamps, and hoses. It fits both turbo and non-turbo models .
  • DeatschWerks DW200 (255 LPH) – Another excellent choice for turbocharged Eclipses and EVO models. It flows 255 LPH at 40 psi and features a quiet turbine impeller. It is compatible with ethanol-based fuels and comes with a 3-year warranty. The DW200 is specifically designed for 1995-1999 Eclipse GS-T and GSX models .
  • Walbro 190 LPH – A good middle-ground option for mild bolt-on modifications like an intake, header, and exhaust. It flows enough fuel for most naturally aspirated performance builds .

Important: When installing a high-flow pump, especially the 255 LPH models, you may need to upgrade your fuel pressure regulator or install a return-style fuel system to avoid over-fueling the engine. Always check the fuel pressure after installation.

Interchangeable Fuel Pumps from Other Mitsubishi Models

If you are having trouble finding a specific pump for the 1999 Eclipse, you can use a fuel pump from a compatible Mitsubishi model. The 1995-1999 Eclipse shares its fuel system with the Mitsubishi Talon (same platform). For the 2.0L turbo engine, the pump can also be swapped from a Mitsubishi Galant or Mitsubishi Lancer Evolution IV, though minor modifications may be required for the Evo pump .

For the 2000-2005 Eclipse (3rd generation), the fuel pump is compatible with the Mitsubishi Galant of the same era with the 2.4L or 3.0L engine. The 2006-2012 Eclipse shares its pump with the Mitsubishi Endeavor and Outlander . Always verify the electrical connector and mounting points before purchasing a cross-model pump.

Step-by-Step Guide to Replacing the Fuel Pump on a 1999 Mitsubishi Eclipse

Replacing the fuel pump on a 1999 Eclipse is a straightforward job that takes about 2 to 4 hours. The pump is accessed through an inspection panel under the rear seat, so you do not need to drop the fuel tank .

Tools and Materials You Will Need:

  • Replacement fuel pump (with install kit if applicable)
  • Wrench set
  • Flathead and Phillips screwdrivers
  • Rubber mallet
  • Flashlight
  • Safety goggles
  • Bucket (to catch fuel spillage)
  • Shop rags
  • Penetrating oil (WD-40)
  • Silver sharpie or marker

Step 1: Prepare the Vehicle

  • Make sure the gas tank is below a quarter full. This minimizes fuel spillage and makes it easier to remove the pump assembly .
  • Relieve the fuel system pressure. Locate the fuel pump relay in the fuse box and remove it. Start the engine and let it idle until it stalls. Then crank the engine for a few seconds to ensure all pressure is released.
  • Disconnect the negative battery cable with a wrench. This prevents any electrical sparks during the repair .

Step 2: Access the Fuel Pump

  • Remove the rear seat cushion. Pull the seat stopper out and lift the lower cushion upward. The seat comes out easily .
  • On the passenger side of the vehicle, you will see a metal inspection cover. Remove the screws or bolts holding this cover in place. Lift the cover to expose the fuel pump assembly .

Step 3: Disconnect the Old Fuel Pump

  • Carefully disconnect the fuel lines from the pump assembly. There are two lines: a fuel feed line and a fuel return line. Fuel may spill out, so have a bucket and rags ready. Wear safety goggles to protect your eyes .
  • Unplug the electrical harness connector from the top of the pump assembly.
  • If your vehicle has all-wheel drive, use a wrench to remove the locking ring that holds the pump assembly in place. On front-wheel drive models, the ring may be threaded and can be removed with a screwdriver and rubber mallet. Tap the ring counterclockwise to loosen it .
  • Gently lift the fuel pump assembly out of the tank. Be careful of the fuel level sending unit (the float arm) that hangs below the assembly. Tilt the assembly to clear the tank opening and place it in the bucket .

Step 4: Install the New Fuel Pump

  • If you bought a complete pump assembly, you can install it directly. If you bought just the pump motor, you will need to disassemble the old assembly. Remove the fuel filter/ pump from the reservoir housing by releasing the tabs. Disconnect the electrical connections and transfer the fuel strainer (pickup sock) to the new pump .
  • Install the new pump into the fuel tank. Make sure the float arm is properly positioned and does not hit the sides of the tank.
  • Tighten the locking ring by hand, then use a screwdriver and mallet to tap it clockwise until it is snug. Do not overtighten.
  • Reconnect the fuel lines and the electrical harness. Make sure the connections are secure.

Step 5: Test and Finish

  • Reinstall the inspection cover and the rear seat cushion.
  • Reconnect the negative battery cable.
  • Turn the ignition key to the ON position (do not start the engine) for 2-3 seconds to prime the fuel system. Repeat this a few times to build pressure.
  • Check for any fuel leaks around the pump assembly and fuel line connections.
  • Start the engine and let it idle. Listen for unusual noises and check for leaks again .

If you see or smell gasoline at any point, do not drive the car. Have it towed to a shop for inspection.

Cost of Fuel Pump Replacement

The cost of a fuel pump replacement for a 1999 Mitsubishi Eclipse varies depending on the part and labor. The average national cost for a fuel pump replacement across all vehicles is between $611 and $894, including parts and labor. For a 1999 Eclipse, the part itself can range from $48 for a basic aftermarket pump to $110 for a high-performance Walbro or DeatschWerks unit . If you do the job yourself, you save on labor costs. If you have a shop do it, expect to pay $200 to $400 for labor on top of the part cost.

Why You Should Not Delay Fuel Pump Replacement

A bad fuel pump can cause more than just inconvenience. When the pump fails completely, the engine will not start, leaving you stranded. More importantly, a failing pump can cause the engine to run lean (too much air, not enough fuel). This can lead to overheating, engine knocking, and potential damage to the pistons and valves. The fuel pump also contains a strainer that filters debris from the fuel. If the pump is weak, debris can bypass the filter and clog the fuel injectors . Replacing the pump at the first sign of trouble is always cheaper than repairing engine damage.

Why Choose KEMSO for Your 1999 Mitsubishi Eclipse Fuel Pump

When it comes to reliability and performance, KEMSO stands out as a trusted brand for fuel pump replacements. KEMSO fuel pumps are designed as high-performance, OEM replacement units that meet or exceed the original factory specifications. Whether you need a pump for a stock 2.0L engine or a high-output turbocharged setup, KEMSO has you covered.

What sets KEMSO apart:

  • High Performance – KEMSO pumps are engineered to deliver consistent fuel pressure and flow, ensuring your Eclipse runs smoothly under all driving conditions. They are built with durable materials that resist wear and corrosion.
  • OEM Replacement – Every KEMSO fuel pump is a direct fit for the 1999 Mitsubishi Eclipse. No modifications, adapters, or special tools are required. The pump comes with the necessary gaskets and seals for a clean installation.
  • Lifetime Warranty – KEMSO backs every fuel pump with a comprehensive lifetime warranty. If the pump fails due to a manufacturing defect, KEMSO will replace it free of charge. This gives you peace of mind that your investment is protected for as long as you own the vehicle.

Visit the KEMSO website to browse their selection of fuel pumps and find the perfect fit for your 1999 Mitsubishi Eclipse: https://www.kemsoracing.com/

Final Thoughts

The 1999 Mitsubishi Eclipse is a reliable and fun car, but like any vehicle with over two decades of use, the fuel pump will eventually need to be replaced. Recognizing the symptoms early and choosing the right replacement part can save you time, money, and frustration. Whether you opt for a budget-friendly standard pump or a high-flow performance unit for a turbocharged build, the key is to use a quality part that matches your engine’s requirements. The installation process is straightforward and can be completed in a few hours with basic tools. If you are unsure about any step, consult a professional mechanic. Keep your Eclipse running strong with a reliable fuel pump.

For a high-quality, lifetime-warranted fuel pump that fits your 1999 Mitsubishi Eclipse perfectly, check out KEMSO at https://www.kemsoracing.com/.


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