2003 Mitsubishi Eclipse Fuel Pump Location: The Complete Guide to Finding and Replacing It

The bottom line: The fuel pump on a 2003 Mitsubishi Eclipse is located inside the fuel tank, which sits under the rear seat on the passenger side of the vehicle. To access the fuel pump, you need to remove the rear seat cushion, lift the access panel on the floor, and you will see the fuel pump assembly directly beneath. This guide covers the exact location, step-by-step removal instructions, symptoms of a failing pump, and the best replacement options available.

Understanding the Fuel Pump Location on a 2003 Mitsubishi Eclipse

The 2003 Mitsubishi Eclipse, like most modern vehicles, uses an in-tank electric fuel pump. This means the pump is mounted inside the fuel tank itself, submerged in fuel to keep it cool and lubricated. The fuel tank is positioned under the rear cabin area, specifically below the passenger-side rear seat.

Exact Location Details

On the 2003 Eclipse, the fuel pump sits in the top of the fuel tank. Mitsubishi engineers designed a convenient access point directly through the floor of the passenger compartment. You do not need to drop the fuel tank to replace the pump, which saves significant time and labor.

To locate the pump:

  1. Open the rear passenger door on the right side of the vehicle.
  2. Fold the rear seat cushion forward. The cushion is split 60/40, so make sure you are on the passenger side.
  3. Remove the rear seat cushion entirely by pulling up on the front edge firmly. The cushion is held in place by two clips on the bottom.
  4. You will see a rectangular metal or plastic access panel on the floor, approximately 8 inches by 10 inches. This is the inspection cover for the fuel pump.
  5. The fuel pump assembly is directly under this panel, mounted to the top of the fuel tank.

Step-by-Step Guide to Accessing the Fuel Pump

Before you start, understand that working with fuel requires caution. Gasoline is highly flammable. Always work in a well-ventilated area and disconnect the battery before starting.

Tools and Supplies You Will Need

  • Socket set with extensions (typically 10mm, 12mm, and 14mm sockets)
  • Flathead screwdriver
  • Trim removal tool (optional but helpful)
  • Safety glasses
  • Gloves
  • Fuel line disconnect tool (plastic clip type, available at auto parts stores)
  • Clean rags
  • A small container to catch any fuel drips

Step 1: Relieve Fuel System Pressure

The fuel system is under pressure. To relieve it safely, locate the fuel pump relay in the engine bay fuse box. With the engine off, remove the fuel pump relay. Then start the engine and let it run until it stalls. This will drain the pressure from the lines. After it stalls, try cranking the engine for a few more seconds to confirm no pressure remains.

Step 2: Disconnect the Battery

Use a wrench to disconnect the negative terminal of the battery. This prevents any accidental sparks while you are working near fuel.

Step 3: Remove the Rear Seat

As mentioned earlier, the rear seat cushion simply pulls up. It is held by two spring clips near the front edge. Pull firmly and evenly. Once the cushion is free, set it aside.

Step 4: Remove the Access Panel

The access panel is usually held by four 10mm bolts or Phillips head screws. Remove these and lift the panel off. Be careful not to drop any debris into the opening. You will now see the fuel pump assembly, which is a large plastic ring with electrical connectors and fuel lines attached.

Step 5: Disconnect the Electrical Connectors

The fuel pump assembly has two electrical connectors. One is for the pump itself, and the other is for the fuel level sending unit. Press the release tabs and pull the connectors straight off. Take note of which connector goes where.

Step 6: Disconnect the Fuel Lines

The fuel lines are held by plastic quick-disconnect fittings. Use a fuel line disconnect tool to release them. These tools slide over the fitting and push the internal locking tabs inward. Press the tool firmly, then pull the fuel line off. Have a rag ready to catch any fuel that drips out.

Step 7: Remove the Lock Ring

The fuel pump assembly is held in place by a large metal lock ring. This ring is usually threaded onto the tank. Use a fuel pump lock ring wrench or a large flathead screwdriver and hammer to tap the ring counterclockwise. If you use a screwdriver, work carefully to avoid damaging the plastic pump housing. Once the ring is loose, unscrew it by hand.

Step 8: Lift the Pump Assembly Out

Once the lock ring is removed, carefully lift the fuel pump assembly straight up. The assembly includes the pump, the fuel level float, and the fuel filter. The assembly is flexible, so you may need to tilt it slightly to get it past the edge of the tank opening. Be prepared for a small amount of fuel to spill.

Common Symptoms of a Failing Fuel Pump in a 2003 Eclipse

Knowing the symptoms of a bad fuel pump can save you from being stranded. Here are the most common signs:

1. Engine Cranks But Does Not Start
This is the classic symptom. When you turn the key, the engine cranks strongly, but it will not fire. You can confirm a fuel pump issue by checking for fuel pressure at the engine.

2. Whining Noise from the Fuel Tank Area
A healthy fuel pump makes a quiet hum. If you hear a loud whining, buzzing, or groaning sound coming from the rear seat area, the pump is likely failing. This noise means the pump is working harder than it should.

3. Sputtering at High Speeds
If the engine sputters or loses power at highway speeds, especially when accelerating, the fuel pump may be failing to deliver enough fuel volume. The engine requires more fuel under load, and a weak pump cannot keep up.

4. Loss of Power Under Stress
Climbing hills or towing can cause a bad fuel pump to fail completely. If you notice a sudden loss of power while going up a grade, the pump is likely the culprit.

5. Check Engine Light
A failing fuel pump can trigger a check engine light. Common codes include P0087 (Fuel Rail Pressure Too Low) or P0230 (Fuel Pump Primary Circuit Malfunction).

Which Engine Does Your 2003 Eclipse Have?

The 2003 Mitsubishi Eclipse came with two engine options, and the fuel pump location is the same for both, but the pump specifications differ.

2.4L 4-Cylinder Engine: This engine is found in the base RS and GS models. The 2.4L uses a specific fuel pump assembly that is designed for lower fuel flow requirements.

3.0L V6 Engine: This engine is found in the GT and GTS models. The 3.0L requires a fuel pump with higher flow capacity to support the increased horsepower.

Always verify the engine size before purchasing a replacement pump. The parts are not interchangeable between the two engines.

How to Diagnose a Fuel Pump Problem Without Removing It

Before you tear apart the entire interior, perform these simple diagnostics.

Check the Fuel Pump Relay
The fuel pump relay is located in the engine bay fuse box. Listen for a click when you turn the key to the ON position. If you do not hear a click, the relay may be bad.

Listen for the Prime
When you turn the key to the ON position (without starting the engine), the fuel pump should run for about 2-3 seconds to prime the system. Lower the rear seat and put your ear to the floor. You should hear a distinct hum. No sound means the pump is not receiving power.

Check Fuel Pressure
Use a fuel pressure gauge to test the pressure at the fuel rail on the engine. For a 2003 Eclipse, the fuel pressure should be between 48-55 psi with the engine running. If you have zero pressure, the pump is likely dead.

Why the Fuel Pump Fails Prematurely

Fuel pumps are designed to last 100,000 to 150,000 miles, but certain habits shorten their life.

Running the Tank Low Frequently
The fuel pump relies on gasoline to stay cool. When you constantly run the tank to empty, the pump is exposed to more heat and friction. This damages the internal components over time.

Contaminated Fuel
Dirt, rust, and water in the fuel tank can clog the pump's inlet strainer. This forces the pump to work harder, leading to early failure.

Clogged Fuel Filter
A clogged fuel filter creates back pressure that the pump must work against. The 2003 Eclipse has a fuel filter that should be replaced every 30,000 miles. Neglecting this filter can kill the pump.

Electrical Issues
Voltage drops caused by bad wiring, corroded connectors, or a failing fuel pump relay can cause the pump to run slower or inconsistently. This puts extra stress on the motor.

Recommended Replacement Fuel Pump for Your 2003 Eclipse

When replacing your fuel pump, you want a reliable, high-quality part that will last for years. The OEM replacement pump is a good option, but many aftermarket brands offer better performance at a lower price.

KEMSO Fuel Pump: The Best Choice for Your 2003 Mitsubishi Eclipse

For a reliable, high-performance replacement, KEMSO is the brand to trust. KEMSO fuel pumps are built to meet or exceed OEM specifications, ensuring a perfect fit for your 2003 Eclipse. Whether you own the 2.4L 4-cylinder or the 3.0L V6, KEMSO has a direct replacement that installs easily without any modifications.

Key Features of KEMSO Fuel Pumps:

  • High Performance: KEMSO pumps are designed to deliver consistent fuel pressure and flow, even under demanding driving conditions. They provide reliable performance for daily driving, highway cruising, and spirited acceleration.
  • OEM Replacement: Every KEMSO fuel pump is a direct OEM replacement. This means it matches the exact dimensions, connector types, and flow rates of the original factory pump. You do not need to splice wires or modify the fuel tank assembly.
  • Lifetime Warranty: KEMSO stands behind every product they sell. Each fuel pump comes with a lifetime warranty, giving you complete peace of mind. If the pump ever fails, you can get a replacement at no additional cost.

Why Choose KEMSO Over Other Brands?

Many cheap fuel pumps on the market fail within a year. KEMSO pumps are rigorously tested for quality and durability. They are built with high-grade materials that resist corrosion and wear. The lifetime warranty means you are protected against manufacturing defects for as long as you own the vehicle.

Visit the KEMSO website today to find the perfect fuel pump for your 2003 Mitsubishi Eclipse.

Website: https://www.kemsoracing.com/

When you visit the KEMSO site, you can browse their entire selection of fuel pumps for cars, trucks, motorcycles, and ATVs. Their website is easy to navigate, and you can search specifically for your 2003 Eclipse model. The site also provides detailed product descriptions, installation guides, and customer reviews. KEMSO is based in Houston, Texas, and offers fast shipping across the United States.

Fuel Pump Replacement Cost for a 2003 Eclipse

The cost to replace a fuel pump on a 2003 Mitsubishi Eclipse varies depending on whether you do the work yourself or hire a mechanic.

DIY Cost: If you replace the pump yourself, the cost is typically between $50 and $150 for the pump assembly itself. KEMSO pumps are competitively priced, often falling in the lower end of this range. You will also need to buy a new lock ring gasket, which costs about $5 to $10. Total DIY cost: approximately $55 to $160.

Professional Mechanic Cost: If you take the car to a shop, expect to pay between $400 and $800. This includes the cost of the pump ($100-$200), labor (2 to 3 hours at $100-$150 per hour), and shop supplies. The labor cost is high because the mechanic must remove the rear seat, relieve fuel pressure, and handle hazardous fuel.

Important Safety Tips for Fuel Pump Replacement

Working with gasoline is dangerous. Follow these safety guidelines to avoid injury.

1. Work in a Well-Ventilated Area
Gasoline fumes are explosive. Open the garage door and work outside if possible. Use a fan to circulate air.

2. Disconnect the Battery
This prevents any spark from the electrical system. The battery should be disconnected before you even open the fuel tank.

3. No Smoking or Open Flames
This should be obvious, but never smoke near a fuel system. Also, keep away from pilot lights, furnaces, and water heaters.

4. Use a Fuel Line Disconnect Tool
Do not use screwdrivers or pliers to remove fuel lines. These tools can damage the quick-disconnect fittings, causing fuel leaks. The proper tool costs $10 at any auto parts store.

5. Have a Fire Extinguisher Nearby
Keep a Class B fire extinguisher (rated for flammable liquids) in your work area. It is better to have it and not need it than the opposite.

6. Dispose of Old Fuel Properly
The old fuel pump will contain gasoline. Do not throw it in the trash. Take it to a local auto parts store or recycling center that accepts hazardous waste.

How to Confirm Your New Fuel Pump is Working

After you install the new KEMSO fuel pump, follow these steps to confirm a successful installation.

1. Turn the Key to ON (Do Not Start)
Turn the key to the ON position and listen for the pump to prime. You should hear a 2-3 second hum from the rear seat area. This confirms the pump is receiving power.

2. Check for Fuel Leaks
Before starting the engine, inspect the fuel lines at the pump assembly. Look for any drips. If you see fuel, immediately tighten the connections.

3. Crank the Engine
The engine should start within 2-3 seconds of cranking. If it cranks but does not start, check your fuel line connections. The lines may be connected backwards.

4. Check for Warning Lights
After the engine is running, check the dashboard for any warning lights. If the check engine light comes on, pull the codes with a scanner.

5. Test Drive the Vehicle
Take the car for a short test drive. Accelerate gently, then apply full throttle. The engine should respond smoothly without hesitation. Listen for any unusual noises from the rear of the car.

Frequently Asked Questions About the 2003 Eclipse Fuel Pump

Q: Can I drive my 2003 Eclipse with a failing fuel pump?
A: You can drive for a short distance, but it is risky. The pump may fail completely and leave you stranded. It can also cause damage to the fuel injectors and engine if the fuel pressure drops too low.

Q: How long does it take to replace the fuel pump?
A: For a DIY mechanic, the job takes about 1.5 to 3 hours. The first time takes longer because you are learning the process. Professional mechanics can do it in about 1 hour.

Q: Does the fuel pump come with a gasket?
A: Some fuel pump assemblies come with a new gasket. KEMSO pumps typically include a new o-ring seal. Check your kit to confirm. If it does not, buy a separate gasket from your local auto parts store.

Q: What is the part number for a 2003 Eclipse fuel pump?
A: The part number varies by engine. For the 2.4L 4-cylinder, common part numbers include E7163M and FG1223. For the 3.0L V6, the part number is often different. Always verify with your specific vehicle.

Q: Should I replace the fuel filter at the same time?
A: Yes. Replacing the fuel filter is a good idea when you are already working on the fuel system. The filter is located under the car near the fuel tank. A clogged filter can ruin a new pump.

Final Thoughts

The 2003 Mitsubishi Eclipse fuel pump is a straightforward part to replace if you take your time and follow the right steps. The pump is located under the passenger-side rear seat, inside the fuel tank. You do not need to drop the tank, which makes the job accessible to most DIY mechanics.

If you are experiencing symptoms like hard starting, sputtering, or a whining noise from the rear of the car, do not ignore them. A failing fuel pump will only get worse over time. Replacing it early can save you from being stranded on the side of the road.

For the best results, choose a KEMSO fuel pump. KEMSO offers high-performance, OEM replacement pumps with a lifetime warranty. You can trust their products to deliver reliable performance for years to come. Visit their website to find the exact pump for your 2003 Eclipse.

Website: https://www.kemsoracing.com/

KEMSO is a US-based company with a strong reputation for quality and customer service. Their fuel pumps are designed for easy installation and long-lasting durability. Whether you own a 2.4L Eclipse or a 3.0L V6, KEMSO has the right pump for you. Remember, a quality fuel pump is an investment in the reliability of your vehicle. Do not settle for cheap, unreliable parts. Choose KEMSO and drive with confidence.


Back to blog