Walbro fuel pump installation

[2Rusty]

This thread will go over the process of replacing a stock fuel pump with a new pump from Walbro. I chose to go with the Walbro 190lph but the install should be exactly the same for those who choose the Walbro 255lph high pressure pump as the two pumps are identicle. I hope it's also helpful for those who simply want to replace their fuel pump with a new OE unit or find themselves only needing to replace the in tank fuel filter for that matter.

The Walbro came with very clear directions and I was pleasantly surprised at how straightforward and easy the install was. Tools that were needed: regular philips head screwdriver (preferably w/magnetized head), set of very small wrenches, set of small sockets and ratchet, pliers, wire cutters & wire crimper.

**Warning** This project has the potential to be very dangerous to your car, to yourself and others around you. Be smart and safety minded as you are essentially opening up a large pool of gasoline inside your car. Have an extinguisher ready somewhere, keep sparks and electricity away, work in a well ventilated area, no smoking and all that good stuff. I will not be responsible for anyone that causes a fire or is burned while doing this install.

[2Rusty]

1st off I would recommend doing the install with a half tank or less of gas but it's not mandatory.

Next you should relieve fuel pressure. The proper way to do this according to the Mazda shop manual is 1. start engine 2. disconnect the circuit opening relay 3. after engine stalls, turn off the ignition 4. reconnect the circuit opening relay.
I didn't bother doing all this although it's the smartest and safest way to do it. I simply unscrewed the gas cap and dealt with any left over fuel pressure as I went along. If you do not know where to locate the fuel pump circuit opening relay look at this pic provided by magik8. I hope he does not mind my linking to it.

Obviously you now need to disconnect the battery completely. In fact it's probably a good idea to remove the battery from the car entirely just to be safe.

OK, with the prep work out of the way you should remove the back seat cushion. This is very simple! Pull the carpet out a bit from under the cushion and lift the cushion up gently. You should find two little white clips, one on the right side and one on the left side. Push the clips in and the seat should come up with ease. I apologize for the poor quality but when you get this far it should look like this:

[2Rusty]

Now undo the two wiring harnesses on top of the service hole cover and use a philips head screw driver to remove the four screws holding it down. As always put the screws somewhere where they will not be lost. Remove the service hole cover. You will see another wiring harness and a ground wire. Disconnect the harness and use a small ratchet and socket or wrench ( I do not know size) to take the ground wire off.

[2Rusty]

Push the retainer clips back on the fuel hoses. I used a pair of soft pliers to gently twist the hoses off the fittings. Be careful! You do not want to damage these hoses. Also be aware that when you do this some fuel will come out and it may still be pressurized. Also remove the eight screws holding the fuel pump assembly down with your philips head. These screws are quite small and if you are not careful they will fall down where they will never see the light of day again. This is why I suggest a magnetized screw driver for the added security. The fuel pump cover does have a gasket on it so a tight seal is important.

[2Rusty]

Remove the fuel pump assembly. This is tricky because the filter and fuel gauge level stick out in different directions. Be patient and go slow. You'll get it. Have a clean container ready to put the assambly into. At this time take notice of which direction the filter sticks out from the assembly. This will come in handy later when attaching the new pump.

[2Rusty]

Now, down to business. The assembly will have two wiring harnesses on it. One is for the fuel gauge level and the other is for the pump. Do not touch anything having to do with the fuel gauge level. Go ahead and remove the nuts holding the wires to the top of the fuel pump. This is where the small wrenches come in. Again I do not remember what size but they are different sizes. A pair of pliers can be used as well.

Now take your philips head and remove the screw at the bottom of the assembly which holds the pump in place. This screw wasn't rusty or anything but it gave me a terrible time. I ended up taking some pliers and clamping around the edges. Yes, the screw got a little torn up but by no means was it unusable. It was a better alternative to stripping it with the screw driver. You should now be able to unclip the metal piece holding the pump in place. Go ahead and take the big rubber band off at this time.

[2Rusty]

Don't worry about taking the old filter off the pump or the old rubber fuel pump isolator at the bottom. You can discard the isolator. The Walbro kit will supply a new isolator and filter. Remove the old fuel pump from the assembly. It should take some effort to pull the pump out of the connection but never fear, it will pop out.

Get the Walbro. Attach the wiring harness that came with it.

[2Rusty]

Slide the foam cylinder over the pump. Looks like a beer can coozie.

Slap the new fuel filter on the bottom. There is a small filter retainer O-ring which secures the new filter on the pump. It's easy to miss so make sure you put it on. It was a tight fit but I used a pair of needle nose pliers the push the retainer over the little post. Here's an out of focus pic:

[2Rusty]

Now take a look at the old fuel pump you will notice a brown plastic spacer at the top. Take the spacer off. Remove the rubber O-ring stuck in the fuel pump connection in the assembly. Replace it with the new O-ring supplied in the Walbro install kit. Slide the spacer over the Walbro and push the new fuel filter into the assembly. Remember which way the fuel filter stuck out from the assembly? This is where that tip comes in to play. Align the fuel pump to the right position against the bracket and slide the big rubber band over it. Push the new rubber isolator onto the bottom of the pump and finally reattach the metal retainer to the pump and bracket and screw it in place. It should look like this:

[2Rusty]

Now all that's left to do is the wiring. Take your wire cutters and cut the ends off all four wires. The blue and red wires are positive and the black wires are negative. How you connect them is up to you. I used the butt splices supplied with the Walbro install kit to crimp the wires together and it looks like this:

[2Rusty]

Reinstall the assembly. Reconnect the battery. Turn the ignition to the accsessory position for about 10 seconds to let the new pump repressurize the fuel system. Start the car. Mine started right up. No explosion? Good. Take it for a drive.

Here's a pic of everything I had left over between the old fuel pump and the Walbro install kit for your comparison:

[Panther37]

Originally posted by 2Rusty
Now, down to business. The assembly will have two wiring harnesses on it. One is for the fuel gauge level and the other is for the pump. Do not touch anything having to do with the fuel gauge level. Go ahead and remove the nuts holding the wires to the top of the fuel pump. This is where the small wrenches come in. Again I do not remember what size but they are different sizes. A pair of pliers can be used as well.

The nut sizes are 7mm and 8mm

[Panther37]

Since the pics have gone down [again] here are two that I have:

[SixSick6]

Here are some from an old thread: http://www.mx6.com/forums/showthread.php?t=112262 (Grrrr, Fuel Pump)

[Panther37]

Comments can be found here: http://www.mx6.com/forums/1g-mx6-gen...tallation.html (Comments On: Walbro fuel pump installation)