How To Install a Fuel Pump in a S14

The Nissan 240SX has enjoyed a revival of sorts, with the surge of motorsport drifting popularity. The very same modders and tuners that turned their backs on the 240SX in the 90s, are now enjoying the benefits of a lightweight rear drive coupe.

Couple this rise in popularity with the many engine swaps from LS1 and RB25 to 2JZGTE, and you’ve got a potent recipe. When you are swapping in a different motor into your Nissan 240SX, you will need the supporting fuel mods to support the new motor and turbo.

This is what our How To Install a Fuel Pump in a S14 guide is for, and we’ll be installing an aftermarket performance fuel pump in a 1996 Nissan 240SX. This 240SX has a RB20DET swap in it, and we’ll be installing a Walbro 255 High Pressure pump.

Tools you will need to perform this fuel pump install

• Wire strippers
• 10mm socket
• pump kit part number GSS342-400-954
• needle nose pliers
• Phillips screwdriver
• hammer and flathead screwdriver or chisel

Before you begin our How To Install a Fuel Pump in a S14 DIY article, it’s a good idea to disconnect the negative terminal on your battery. If you are not familiar with safety precautions that you must take while working with gas fumes or fuel, check here for our article.

You will have to remove your rear seat to access the panel behind the seat. To do this pull up on the tabs of your backseat and pull downward. The S14 trunk mat can be removed by pulling on the tabs in that hold it down.

The fuel tank cover is directly under the carpet matting, reach into the trunk area and pull back on the mat. This will allow you to unscrew the top of the fuel tank cover.

With the cover removed, you can now reach the top of the fuel pump assembly which is sealed by way of a plastic o-ring. First unplug the electrical connectors and the hoses that lead out of the fuel pump assembly.

Push the electrical connectors out of the way and then use your chisel or flat head screwdriver to turn the plastic oring and seal counterclockwise to remove.

Once this plastic oring has been removed, you can pull up on the fuel pump assembly to remove the fuel pump, fuel pump filter (sock) and the hangers.

Because the 1995-1998 Nissan 240SX has the fuel tank incorporated into the trunk tunnel, this can be a little more difficult than the 1989-1994 Nissan 240SX (S13). Once you’ve got the entire fuel pump assembly removed, you must disconnect the electrical connections that lead to the top of the fuel pump assembly.

Now that the three prong power connector has been removed, you can pull the pump off the fuel pump assembly by pushing outwards from the rubber grommet. The stock Nissan fuel pump is connected by electrical spades that are screwed onto the fuel pump connectors.

Unscrew these connectors and remove the pump from the hanger. Now install the new Walbro fuel tank filter and secure it with the small metal oring. Make sure this metal oring is firmly seated against the bottom of your fuel pump, so that it stays put.

Now the Walbro 255 HP fuel outlet port must be connected to the fuel hose, make sure to transfer over the metal clips to ensure a seal. Re-install the fuel pump back onto the fuel pump bracket and then tighten.

You may or may not need to cut off the metal connector spades that fed power and ground to your stock fuel pump. If you do choose to cut this wire, it’s important to orientate the wires so that they never touch or no bare wire ever touches. You can also opt to extend these power wires, but you should not use butt connectors as they can come loose over time and cause further issues.

The red wire is switched power, the red wire with white stripe is the low reference ground signal. Now tighten the bottom grommet and screw to make sure your new Walbro does not move and you are ready to reconnect the three pin power harness.

Now with your fuel pump assembly ready to drop into your S14. Now get the rubber o-ring you removed earlier during the How To Install a Fuel Pump in a S14 guide and inspect it for any tears or damage. If there is any damage to this rubber o-ring, or pinching along the sides it’s best to discard this oring and purchase a replacement.

The Nissan part number for this oring is 17342-79900, and it’s a crucial part of learning how to install a fuel pump in a S14 DIY article. This o-ring provides a positive seal to your fuel tank and without this seal your S14 will not start.

Now carefully put back the plastic ring and slowly screw it back onto place. Use your hammer and chisel to put the finishing touches on it. Now all that’s left is to reconnect the rubber hoses and the 2 electrical connectors.

You have now completed our How To Install a Fuel Pump in a S14 guide, remember that your car may take a few cranks to start as all the fuel has been emptied from the rail and the lines.

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