Mitsubishi Evo X Fuel Pump Relay: Identification and Location
If your Lancer Evolution X cranks but will not start, or the fuel pump stays silent when you switch the ignition on, the relay that powers the pump is a sensible early check. This guide explains where Evo X owners usually look for the fuel pump relay, how to confirm you have the right part instead of trusting a forum photo, and what a relay check can and cannot tell you about the rest of the fuel system.
Where the Evo X fuel pump relay is located
The fuel pump relay on the Evo X sits in one of the car's fuse and relay boxes, not at the fuel tank. The usual starting point is the relay box under the hood. Its cover carries a printed diagram that labels each fuse and relay position, and that label, rather than a relay's shape or color, is how you identify the fuel pump relay.
If the under-hood cover does not list a fuel pump relay, check the interior junction block below the driver's side of the dashboard and the fuse section of the owner's manual. Layouts can differ by model year and market, so treat any single photo or forum description as a hint rather than proof. Some diagrams also list a separate fuel pump fuse. Note it while you are there, because a blown fuse produces the same no-start symptom as a failed relay.
How the fuel pump relay works
The relay is an electrically operated switch. The engine control unit energizes the relay's coil, the internal contacts close, and battery power flows through the fuse to the in-tank fuel pump. When you turn the key or press the start button without cranking, the control unit normally runs the pump for a few seconds to build fuel pressure, then switches it off until it sees the engine turning. That short hum from the rear of the car at key-on is the prime cycle.
Once running, the pump pushes gasoline through the fuel filter to the fuel rail and the injectors of the turbocharged 2.0-liter four-cylinder. The relay only switches power on and off. It does not regulate fuel pressure or meter fuel. A relay with worn or burned contacts can cause no prime, a crank-no-start, or intermittent stalling. A relay that works correctly does not rule out a weak pump, a clogged filter, a pressure regulation fault or wiring trouble further down the circuit.
What changes the answer
Factory configuration matters first. Model year and market can change the relay box layout and labeling, and right-hand-drive or imported cars may not match a US-market diagram. Some performance vehicles use more than one fuel pump control element, for example a second relay or a stage that changes pump speed. If your diagram shows more than one fuel-pump-related position, identify each one before drawing conclusions from a single relay.
Modifications matter just as much on this car, because many Evo X examples are tuned. An upgraded fuel pump is often installed with an auxiliary relay and a dedicated power wire, so the relay that actually feeds the pump may be an aftermarket unit mounted elsewhere in the engine bay or trunk. Fuel type affects demand as well. A car tuned for ethanol blends or higher boost asks more of the pump and its wiring than a stock car on premium gasoline, and higher current draw can heat and wear relay contacts and connectors. If you bought the car modified, trace the pump's power feed rather than assuming the factory relay is still in the circuit.
What the owner can do
Start with simple observations. In a quiet place, switch the ignition on without starting the engine and listen near the rear seat or trunk for the pump's prime. Then locate the relay with the cover diagram, inspect the fuse beside it, and look for melted plastic, corrosion or a loose fit in the socket. Feeling a relay click under your fingertip only shows that the coil is working. It does not prove that the contacts can carry pump current.
A practical test is to swap the fuel pump relay with an identical relay from a non-critical circuit in the same box, matching the part number printed on the case, and then check the prime again. If the pump now runs, the original relay is the likely fault. If nothing changes, the problem is elsewhere, such as the fuse, wiring, connector, control signal or the pump itself. Avoid improvised jumper wires across relay socket terminals unless you are following the factory wiring diagram, because a wrong connection can damage the control unit or wiring.
Do not loosen fuel lines or fittings to see whether fuel is reaching the engine. The system holds pressure even after the engine stops, and spraying gasoline creates a fire hazard. If you smell fuel or see wetness around the rail, lines or tank area, stop driving and arrange a proper leak check. Fuel additives may help with some deposit issues, but they will not repair a failed relay, a worn pump or a wiring fault. If the engine runs but feels lean or hesitant, a scan tool that shows fuel trim and stored codes gives more useful direction than guessing at parts.
Limitations and next step
This article cannot confirm the exact relay position for every Evo X model year, market or modified car. The cover diagram on your own relay box and the factory service manual wiring diagram are the authoritative references, and they also give the correct pin identification if voltage testing is needed. Previous repairs, alarm installations and aftermarket fuel pump wiring can all change what you find.
If a known-good relay and an intact fuse do not restore the prime, the next steps are measuring voltage and voltage drop at the pump connector and checking fuel pressure with a proper gauge and procedure. Both are best handled by a qualified technician, especially when the work involves opening the fuel system or reaching the pump inside the tank. A professional is also the right call when the car has upgraded pumps, injectors or a custom tune, because pump supply problems on a boosted engine can lead to lean running under load and serious engine damage.