The Eclipse MFI relay is a 4 pin relay found in the A-21x section of her Mitsubishi 3.0 liter engine only fuse box. This component is mainly responsible because that powering her fuel pump and allowing your Mitsubishi Eclipse to start. Once this relay burns the end your Mitsubishi Eclipse 3.0 liter V6 engine will not start, and also your fuel pump will not rotate on.

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To examine your fuel pump operation, insert your Eclipse ignition crucial and rotate to the “ON” position. If you carry out not hear your fuel pump transforming on, this can be a vast reason why your 3.0 liter Mitsubishi will not start.

Today I’ll be mirroring you just how to test the MFI relay in her 2000 Eclipse v a 3.0 liter V6 engine, come correct any type of fuel pump issues with her Mitsubishi. With time your MFI relay can fail, causing you serious starting issues or compromising her engine. Once your MFI relay starts to fail, you might misdiagnose her crank angle sensor together being the problem.


As previously proclaimed the Eclipse MFI relay is located in her fuse box close to your driver next shock tower. This panel have the right to be lifted off and also you can access the MFI fuse through the fuse chart below.

To accessibility your Mitsubishi MFI relay, open up your fuse box by undoing the locking tabs on her fuse cover.

Once your cover is eliminated you can accessibility the MFI relay. Examine our Mitsubishi Eclipse fuse box diagram come the left to view where this relay is.

In stimulate to finish this experimentation guide for your Eclipse MFI Relay, you will require a digital multimeter. Friend can additionally test this relay using an ohmmeter, and also if friend don’t understand the difference examine out our primer here.

When the Eclipse MFI relay in your Mitsubishi walk bad, the fuel pump and also EFI device will not occupational properly. The part number for this relay is MR538851, and also we’ll start by checking the relay for continuity.

The pins shown in ours Mitsubishi fuel pump relay diagram space signified by the dot as soon as you flip the relay over.

The an initial part of our check is to examine for continuity between PIN 2 and also PIN 3 the the Eclipse MFI relay. Revolve the dial of her multimeter to check out resistance Ω, and also there should be approximately 70 Ω or continuity between these 2 pins.

Now construct wires and run the two wires indigenous MFI relay terminal 2 to the confident battery terminal and also terminal 3 come the an unfavorable battery terminal. At this allude you will recheck for continuity. This time the write-ups to examine are between the MFI relay terminals 1 and 4 if connecting and disconnecting the jumper cable at the an adverse battery terminal.


With the negative battery terminal disconnected pin 1 and also PIN 4 must return an open up loop condition.

When you have actually the an adverse terminal of her battery connected, there need to be less than 2 ohm Ω.

If the relay itself checks out, there’s some poor news in that the fusebox of your 3.0 liter Mitsubishi Eclipse may have actually some worries with the wiring.

The next part of the test will require you to examine the A-18X connector through the MFI relay disconnected. Describe our Eclipse MFI Relay wiring schematic below to match A to ! and also B to 2 and C come 3 and so on.

You will be check the A-18X connector or the fusebox because that this component of the test. Turn the dial of her multimeter to read DC voltage and also turn her Eclipse ignition to the “ON” position.

Now measure the voltage in ~ terminal A of the ENGINE exploit or the fusebox itself.

There have to be 12 volts of DC power at this pin. Now check the pin B position for power, and this too must return 12 volts that battery voltage.

If the terminals at your A-18X terminal inspect out, and also the Eclipse MFI relay checks out, there’s one more cause for her Eclipse no starting.

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If her Eclipse MFI relay return values external of this test, it’s a authorize that this relay has actually gone dead. You will should unplug this relay and also install a new Eclipse fuel pump relay. Once you’ve reconnected a replacement Eclipse MFI relay, rotate your key to the ON position to make certain your fuel pump is activated.

Have any type of questions around our fuel pump relay experimentation tutorial? Leave us a question below and also let united state know!