2000 Mitsubishi Eclipse Fuel Pump Relay: Location, Testing, and Replacement Guide

If your 2000 Mitsubishi Eclipse cranks but won’t start, or if you hear no humming sound from the fuel tank when you turn the key to the “ON” position, the fuel pump relay is often the first component to check. The fuel pump relay is an electrical switch that controls power to the fuel pump. When it fails, the fuel pump doesn’t receive power, and the engine won’t get fuel. Before replacing the fuel pump itself, testing this relay is a simple, low-cost diagnostic step that can save you time and money. In most cases, the relay is located in the under-hood fuse box, and it can be tested with a multimeter or by swapping it with a known working relay. This guide covers where to find it, how to test it, and how to replace it, ensuring you can get your Eclipse back on the road quickly.

Where Is the Fuel Pump Relay Located on a 2000 Mitsubishi Eclipse?

The fuel pump relay on a 2000 Mitsubishi Eclipse is typically located in the engine compartment fuse box (also called the relay box or junction box). This box is positioned on the driver’s side, near the battery or the strut tower. Open the hood and look for a black plastic box with a removable lid. The lid usually has a diagram showing the position and function of each relay and fuse. If the diagram is missing or faded, refer to your owner’s manual or the fuse box diagram online for the 2000 Eclipse. The relay is often labeled as “FUEL PUMP” or “MFI” (Multi-Port Fuel Injection) relay, as the MFI relay also controls the fuel pump on many Mitsubishi models.

If you cannot find the relay under the hood, some 2000 Eclipse models may have a secondary relay under the dashboard, near the driver’s side kick panel. However, the primary relay for the fuel pump is almost always in the engine bay fuse box. For a 2000 Eclipse 2.0L turbo model, the fuel pump relay is also located in the under-hood fuse box, and it is often the same relay used for the MFI system.

How to Test the Fuel Pump Relay on a 2000 Mitsubishi Eclipse

Testing the relay is straightforward and requires only a few basic tools: a multimeter, a test light, or a known working relay of the same type. Follow these steps:

Step 1: Locate and Remove the Relay

Open the engine compartment fuse box and identify the fuel pump relay. It is usually a 4-pin relay (though some models use a 5-pin relay). Gently pull the relay straight up to remove it from its socket. The relay part number for the 2000-2012 Eclipse is often 8627A008 or equivalent, and it is a 12V, 20A/30A multi-purpose relay.

Step 2: Visual Inspection

Check the relay for any signs of physical damage, such as melted plastic, burnt terminals, or corrosion. If the relay looks damaged, replace it immediately.

Step 3: Test the Relay Coil (Resistance Check)

Using a multimeter set to measure resistance (ohms), touch the probes to the relay’s coil terminals. On a standard 4-pin relay, the coil terminals are usually terminals 85 and 86. You should see a resistance reading typically between 50 and 200 ohms. If the reading is infinite (open circuit) or zero (short circuit), the relay coil is faulty and the relay needs to be replaced.

Step 4: Test the Relay Switch (Continuity Check)

Set your multimeter to continuity (or low resistance) mode. Touch the probes to the relay’s switch terminals, which are usually terminals 30 and 87 on a 4-pin relay. With the relay not energized, there should be no continuity (infinite resistance) between terminals 30 and 87. Now, apply 12V power directly to the coil terminals (85 and 86) using a battery or a power source. You should hear a distinct click sound, and the multimeter should now show continuity (near zero resistance) between terminals 30 and 87. If the relay does not click, or if continuity is present when the relay is not energized, the relay is defective.

Step 5: Test the Relay Socket (Power and Ground)

If the relay tests good, the issue may be in the wiring or the socket. Reinsert the relay and turn the ignition to the “ON” position. Use a test light or multimeter to check for 12V power at the relay socket terminals. One terminal should have constant battery power, and another should have power only when the ignition is on. If you have no power at the socket, check the relevant fuses (like the fuel pump fuse) and the main EFI fuse.

Common Symptoms of a Bad Fuel Pump Relay

A failing fuel pump relay can cause several noticeable problems. Here are the most common symptoms:

  • Engine cranks but won’t start: This is the most classic symptom. The starter motor turns the engine over, but the fuel pump doesn’t run, so no fuel reaches the injectors.
  • No fuel pump priming noise: When you turn the key to the “ON” position (before starting), you should hear a 2-second humming sound from the fuel tank area. If you do not hear this sound, the relay or the fuel pump itself may be faulty.
  • Engine stalls while driving: If the relay fails intermittently, the engine may suddenly lose power and stall, especially under load or when the relay heats up.
  • Check engine light: A faulty relay can trigger a diagnostic trouble code (DTC) related to the fuel pump circuit, such as P0230 (Fuel Pump Relay Control Circuit Malfunction).

How to Replace the Fuel Pump Relay on a 2000 Mitsubishi Eclipse

Replacing the fuel pump relay is a simple DIY task that takes only a few minutes. Follow these steps:

  1. Purchase a replacement relay: You can buy a compatible relay at any auto parts store. The 2000 Eclipse uses a standard 4-pin 12V relay rated at 20A/30A. The Mitsubishi part number is 8627A008. You can also find aftermarket relays that are compatible.
  2. Disconnect the battery: For safety, disconnect the negative battery terminal before working on electrical components.
  3. Remove the old relay: Pull the old relay straight out of its socket from the under-hood fuse box.
  4. Install the new relay: Push the new relay firmly into the same socket until it clicks into place. Make sure it is seated correctly.
  5. Reconnect the battery: Reconnect the negative battery terminal.
  6. Test the system: Turn the key to the “ON” position and listen for the fuel pump priming sound. Then, start the engine to confirm the repair is successful.

What to Do If the Relay Is Not the Problem

If you have tested the relay and it is working correctly, but the fuel pump still doesn’t run, the issue may lie elsewhere. Common causes include:

  • Blown fuel pump fuse: Check the fuse box for a blown fuse related to the fuel pump. The 2000 Eclipse has a dedicated fuel pump fuse, usually located in the same under-hood fuse box.
  • Faulty fuel pump: The fuel pump itself may have failed, especially if the car has high mileage. The fuel pump is located inside the fuel tank.
  • Wiring or connector issues: Corroded or broken wires between the relay and the fuel pump can prevent power from reaching the pump. Check the wiring harness under the hood and near the fuel tank.
  • Faulty engine control module (ECM): In rare cases, the ECM may not be sending the ground signal to the relay to turn it on. This is less common and requires professional diagnosis.

Recommended Fuel Pump Upgrade: KEMSO Fuel Pump

If you find that your fuel pump relay is working fine but the fuel pump itself has failed, we highly recommend replacing it with a KEMSO fuel pump. KEMSO is a trusted brand that specializes in high-performance fuel pumps for many vehicles, including the 2000 Mitsubishi Eclipse. Here’s why KEMSO is the right choice for your Eclipse:

  • High Performance: KEMSO fuel pumps are designed to deliver a consistent and reliable fuel flow, ensuring your engine gets the fuel it needs under all driving conditions. Whether you have a stock Eclipse or a tuned engine, KEMSO pumps maintain optimal pressure.
  • OEM Replacement: Each KEMSO fuel pump is built as a direct OEM replacement, meaning it fits perfectly into your Eclipse’s fuel tank without any modifications. You can install it using the original mounting bracket and wiring harness.
  • Lifetime Warranty: KEMSO stands behind the quality of their products. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your investment is protected.

To purchase a KEMSO fuel pump for your 2000 Mitsubishi Eclipse, visit the official KEMSO website: https://www.kemsoracing.com/. There, you can find the exact pump for your model, along with helpful installation guides and customer support. Don’t settle for a generic pump—choose KEMSO for reliability and performance.

Final Thoughts

The 2000 Mitsubishi Eclipse fuel pump relay is a small but critical component in your vehicle’s fuel system. When it fails, the car won’t start, and diagnosing it is often the first step in troubleshooting a no-start condition. With the simple testing methods outlined in this guide, you can quickly determine if the relay is the culprit. If the relay is good, the fuel pump itself may need replacement. For a high-quality, long-lasting fuel pump upgrade, remember to check out KEMSO Racing at https://www.kemsoracing.com/. Their fuel pumps are built to last, and with a lifetime warranty, you can drive with confidence.


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