Engine Installing a Walbro Fuel Pump

Installing a Walbro Fuel Pump

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If you are not planning on installing a return line, use a Supra fuel pump (good up to 600 HP) or a Gen I Walbro pump. If you are planning on doing a return system, go ahead and get the Walbro Gen II pump which is about 3/8" longer than the stock one.

Disconnect your negative battery terminal before starting. Remove the bottom cushion of your rear seat. You'll see a removable plate on the drivers side with some wires running into a grommet in the middle. Pry this open using a flathead. It is affixed with black adheasive.

Have a container and some towels handy before unplugging the fuel line from the top of the gas tank cover. You can try to carefully pinch the hose to reduce the amount of fuel spilt. Relieve the rest of the pressure in the line by letting it drain out into a container.

Unplug the wire harness from the top of the cover and use a rachet set to break loose the screws holding the cover on. You can also use a philips head screw driver, but it's much easier to use a ratched.

With the cover off, carefully lift the fuel pump housing out of the gas tank. You'll need to tilt it to the side and get the fuel level indicater float out first, followed by the filter sock.

Once out, use a small knife or a tiny flat head to pull the retainer clip off the bottom of the unit so that you can remove the filter sock.

Next, remove the fuel pressure regulator. It's the only other metal thing on the underside aside from the pump. All you need to do is pull it straight out. It will be tough as it's held in place with a stick o-ring.

Finally, open up the housing by using a flat head to pop open the clips. Pull the old fuel pump straight out. Carefully remove the cap, the o-ring, and the fitting off the top of the old fuel pump and install them onto your new one.

I'm not sure about the Supra pump, but the Walbro Gen I and Gen II pumps will need a new harness which is usually supplied with the pump. Cut the old harness off and splice the new one on. The wire order is black to black and red to blue.

Reverse your steps to reassemble the unit. Be sure to use the supplied rubber insulator if using the Walbro pump. The insulator is the rubber piece that sits between the bottom of the pump/filter and the housing.

You can use a little bit of motor oil to lubricate the o-rings so that you can plug everything back in. Make sure all the seals are tight.

If you are using the Supra pump, be prepared to make some modifications to the housing to make it fit. You'll need to trim the bottom fuel pump housing cap so that the fuel filter sock can stick out. You may or may not need to use the rubber isolator.

If you are using the Gen II Walbro pump, you will find that it is too long and that you can't get the clips to close, which is why I recommend against getting it unless your doing a return system. If you are stuck with the Gen II pump, you can do the same trick as with the Supra fuel pump, but don't use the rubber isolator.

If the Gen II pump is still too long after doing the above, seperate the return system housing (black plastic) from the top of the fuel pump housing. Trim the top connector on the return system housing by no more than 1/5" so that it sits a little higher. You'll also need to trim the plastic nub in the middle of the underside of the top of the fuel pump housing so that when you put the two pieces back together, everything still sits level. You'll definitely need to lube the o-ring with some oil to get the connector back on.

Once everything is back in place, start up the car. It may take a few tries until the fuel system pressurizes. Check for any leaks. Let the car idle for a minute, then slowly rev it up to 5000 RPMs to check if there's any sputtering. If this happens, there may be a leak somewhere in the housing.

One last note; you may hear a whining sound from the fuel pump. This is normal as it's a high flow pump. Don't let it worry you.