Gallery
Owner: Walbro Pump Install - Mitsubishi Evo 7-9
Before you start this install, make sure your working in a clean area to avoid fuel contamination and disconnect the battery.
1. (IMAGE 1) Start by locating the fuel tank cover located under the rear bench on the drivers side. Remove the screws which secure the cover in place.
2. (IMAGE 2) Locate the "Fuel Pump Module Connector" (circled in the pic). This will release the pressure on the fuel lines. With the harness disconnected, start the car. You should find it runs for a short time before cutting out or doesn't run at all. When the car no longer runs, turn it off and remove the keys from the ignition.
3. Your wire harness should already be disconnected by now. The high pressure and suction hose both use quick disconnects. Remove them by simply squeezing the tabs and pulling them off. A spring clamp holds the return line in place, so grab your needle nose pliers, squeeze it together and push it back up the hose.
4. (IMAGE 3) The are six, 8mm retaining bolts that need to be removed. Removing the rearward 8mm bolts is most easily accomplished with an extension on the ratchet or a nut driver, but you will need to get under the sheet metal to reach the front ones.
5. (IMAGE 4) Once all the connections and 8mm bolts have been removed, you will need to pull the assembly out of the tank. There is little room to move and the retaining ring on top makes difficult since it is wider than the opening. You'll need to remove the retaining ring before pulling the rest of the assembly out of the tank being careful not to manhandle it. As you will see in the pictures, the fuel level sending unit arm/float are connected to it (sticks out the high pressure hose side) and too much force may bend it, which can throw off your fuel gauge reading. Making a note of the fuel level before you start is good practice just to be sure.
6. When you lay the assembly down to work on it, make sure the fuel level sending unit is in the air. Do not lay the pump assembly with the float/arm down and be careful not to hit or bend it while you are working. The fuel pump retainer simply snaps to the main assembly using 3 tabs. Removing the retainer is simple, either by hand or using a flat head screwdriver to pull the tabs away from the main assembly and sliding it down.
7. With the retainer removed, simply pull the pump out of the housing. The wire harness plugged into the top of the pump only extends to the bottom of the assembly, so do not try to pull the pump all the way out. Pull it down and unplug the harness from the top.
8. With the pump removed, you can see the harness and the factory "o-ring" (grommet) still stuck in the outlet. The factory grommet is more like a hat than an o-ring in that it covers the top, as well as a good length of the outlet fitting (see insets).
9. (IMAGE 5) Using the supplied Walbro filter and retaining clip, attach this to the new Walbro pump. Set the filter in place and push the retaining ring on as best as you can (just so the ring doesn't fall off). Place a 5.5mm or equivalent socket over the retaining ring and gently tap it on until it sits flat against the filter housing.
10. (IMAGE 6) The factory harness plugs right into the Walbro 255 pump. Once plugged into the pump, slide it back into the assembly making sure the wires do not bunch up and also making sure that the outlet is located in the correct place. Now the pump is seated, take the rubber isolator and insert onto the bottom of the pump.
11. Now starting with the retaining clip, your ready to put the lot back together in reverse order! Make sure the gasket is replaced onto the assembly properly before it goes back into the tank and make sure the float and fuel level arm are both facing the passenger side of the car.
12. After everything is properly connected, give the car a start to make sure it's getting fuel. Don't be scared if it takes a few cranks before it fires over. Remember, you ran all of the fuel out the line and it needs to fill back up and pressurise again. When the cars starts, replace the steel cover over the pump assembly and then replace the seat.
JOB DONE! Unless you were running lean before the install due to more demand than supply, you will likely want to retune your fuel adjustments down just a tad, but there is no problem without any fuel control at all, it just means you'll run very slightly rich.
With the added flow of the high-volume fuel pump, base fuel pressure has a tendency to increase 5-10psi, which will run you a tad fatter across the board. This added rail pressure may be a "side effect" of the high-flow pump, but by allowing you to lower fuel settings across the board, it has also just increased your margin of "fun" before you hit fuel cut!
For more information or to buy this item from JP4mance Tuning Parts - CLICK HERE