View Full Version : How to install a Walbro 255 LPH Fuel Pump *Approved*

05-09-2007, 11:24 AM
This is a fairly easy install but I think it is also a very important one that some people think they can skip when swapping motors. Upgrade your fuel pump when swapping motors people, it's so easy to do, not that expensive, and will keep you from having problems down the road. I will be installing the typical Walbro 255 lph fuel pump into my S13, which is common to SR and RB swaps. I had this already written up in a less organized fashion so I thought I could clean it up and give some more detail to make it premie project worthy. Let's do this.


Tools/Supplies for this install:
Phillips Head Screwdriver
Socket Wrench
10mm Socket
8mm Socket
Shop Towels/RagsThe first thing you'll want to do, especially when working with the fuel pump, is to disconnect the negative battery terminal. We don't need any sparks when we're working with an open fuel tank. Another thing to note is that the instructions specifically say not to use a soldering gun for any wiring we have to do in this install, with good reason. We'll talk about that more later.

After you have disconnected the negative battery terminal, we are ready to extract the old fuel pump. Remove the carpet and fiberboard insert from your trunk to reveal two gray metal panels on the passenger side of the trunk. Using a phillips head screw driver, remove the smaller of the two gray metal panels. It is secured by two screws. Once the panel is off, there will be a gray and blue connector hidden underneath which we want to disconnect. This is how it should look so far.


Next we want to remove the larger gray metal panel that is held down by four bolts. This requires the use of a 10mm socket wrench. Once all four bolts have been removed, pull the gray metal panel off to reveal another metal panel that acts as the mount for the fuel pump and seals the fuel tank.

After removing the gray panel as we just did, we want to disconnect the two fuel lines that are attached to the panel on the fuel tank. REMEMBER WHICH NIPPLE EACH FUEL LINE WAS ATTACHED TO!!! One of them is the feed line and the other is the return. If you reverse these your car will not start!

EDIT: As some people have mentioned, secure the fuel lines somehow so they don't fall behind the access hole or else you'll have a hell of a time retrieving them.

Once you have marked and removed them, use an 8mm socket to remove the 6 bolts that hold the panel down.


Once you have done this, you are ready to extract the pump from the fuel tank. BE GENTLE when pulling the fuel pump out of the tank. I say this because the gas level sensor is a rather odd shape and will typically catch on the side of the tank when pulling it out. Just be careful and twist/turn the pump in order to get it out. This is what it looks like removed. Note the fuel level sensor sticking out to the left of the pump.


Now that the pump is out of the fuel tank, it is a good idea to cover up the hole to the tank with a shop rag or something to keep anything from falling in. The last thing you want(besides a spark) is to be fishing around in gasoline.


We can now remove the fuel pump from the pump fixture. I was able to remove mine by simply twisting it some. Once it's disconnected from the fixture, you will want to remove the small rubber fuel line that connect the pump to a metal hard line line that feeds through the top of the metal panel. You will also want to remove the two electrical connections. Feel free to cut them if needed, but don't cut them too short near the metal panel. The Walbro fuel pump comes with wires that are pretty long for the install as well as crimp connectors. Here you can see the old fuel pump is disattached from the pump fixture. Look at how nasty that fuel sock is.


You can go ahead and take the new Walbro fuel pump out of it's packaging. The first thing you will want to do is install the fuel sock. It easily connects to the bottom of the fuel pump. Once the sock is on, there is a rubber piece that is used to keep the sock in place and keep the pump snug on the pump fixture. It goes directly over where the sock is mounted, as shown below.


The new Walbro unit comes with a small section of rubber fuel line. Slide it onto the metal hard line on the pump fixture. You may need to trim the rubber fuel line some as it is pretty long unless you want to just push it all the way onto the hard line as I did. You can now place the new Walbro unit back onto the pump fixture. The rubber piece on the bottom near the sock lines up with the bottom part of the pump fixture. While attaching the pump to the fixture, slide the rubber fuel line onto the pump as well. The new pump comes with metal straps to keep the rubber fuel line tight, tighten those down once the line is completely on the fuel pump. Once you get it mounted on the pump fixture, it should look as follows.


Now that the pump is on the fixture, we can attach the wires. The wiring is simple, red to red, black to black. As I mentioned earlier, DO NOT USE A SOLDERING GUN. While some people, myself included, shutter at the sight of crimp connectors, this is one instance where you have to use them. Walbro provides us with two crimp connectors to secure the lines with. Using a pair of pliers, crimp the lines together like mentioned. Make sure they are as tight and secure as you can get them to be. You don't want any sparks in your fuel tank because of a lackluster connection. Here they are connected.


Before we place the pump back into the fuel tank, there is one thing we should take care of. I have read quite a bit about the seal to the fuel tank being compromised due to the rubber gasket expanding and not fitting inside of the groove it is supposed to sit in. In fact, every time I would put gas in my car I could smell it due to this leak. Most people just sever the gasket, trim a small portion off, and put it back in it's place so that it fits. I decided to do that as well as place some liquid gasket around the outside of the groove it sits in to make absolutely sure it was sealed. Since I've had had the car running, I haven't once smelled gasoline. This is a picture of it with the liquid gasket.


With that taken care of, we are now ready to place the new pump into the fuel tank. Carefully slide the pump fixture back into the tank, watching out for the fuel level sensor again. It should go right in as it came out. Before we bolt the fixture down, connect the fuel lines back up to the fixture. The reason we do this before securing the fixture to the tank is because the lines are pretty stiff which makes them hard to connect once the pump fixture is in it's place. Once they are connected, go ahead and bolt the pump fixture back to the fuel tank using an 8mm socket wrench just as before.

Once it is securely bolted down, reconnect the gray and blue electrical connector. Now you are ready to put the gray metal panels back on. Work in the reverse order by reattaching the larger gray panel with the four 10mm bolts first. Once securely fastened, connect the smaller gray panel with the two screws. Go ahead and put the carpet back and you're done!


I had absolutely no problems with my fuel pump install when I got my SR running, so if you follow this guide closely it will work on the first try. :bigok:

06-14-2007, 12:31 AM
your lucky you don't have to deal with the S14 "Twist off" giant access lock.

06-14-2007, 12:35 AM
Just one suggestion of something I would add that I didn't see. It's a good idea to use something to tie the fuel lines up and keep them from falling down behind the access hole. If they do they're a bitch to get back up there and get them re-attached.

Nice write up.

06-14-2007, 12:36 AM
S13 > S14


good write up

06-14-2007, 09:53 AM
Just one suggestion of something I would add that I didn't see. It's a good idea to use something to tie the fuel lines up and keep them from falling down behind the access hole. If they do they're a bitch to get back up there and get them re-attached.

Nice write up.

That actually happened to me... and it took me about 20 minutes to actually get them back into position... effin annoying!

06-14-2007, 10:40 AM
I went ahead and added it to the write up near the top. Thanks for the suggestions!

EDIT: Also fixed some grammatical errors as well as a few quirks in my descriptions.

06-14-2007, 01:13 PM
^not a problem... this is seriously a great write up and when I am ready to change my fuel pump I will most def be using this

08-24-2007, 10:57 PM
This is good to go.