New Fuel Pump Install

Today I installed a new Walbro 400lph fuel pump, replacing my Walbro 255lph fuel pump.

Walbro 255 vs. 400 fuel pumps

This is a 30 minute upgrade if you know what you’re doing. It can take longer if you’re unfamiliar with the S14 fuel system. There are a few things to point out about my Walbro 400 fuel pump that cause me a slight delay:

  1. The plugs it came with do not match up to anything. It’s almost like I had a kit for another vehicle. Just clip the plug and crimp or solder the wires to the connector on the S14.
  2. The rubber isolator does not match up with the Walbro 400 bottom. You have to kind of cram it into place with the bracket. The 255lph fit like a glove, so this is unfortunate that the over-sized base made the isolator a funky fit.
  3. The S14 fuel sock/filter is a tight fit on the 400 but fit perfectly on the 255. You need to use a hammer and a small screwdriver and lightly tap it into place.
  4. Pay attention to the + and – symbols on the fuel pump. My 255 was wired backwards. The black was + and the – was red wire. I followed the wire colors instead of the terminal symbols and wired it backwards the first time, which wasted a lot of my time.

New Walbro 400lph Fuel Pump

Walbro 400lph Fuel Pump

At our last dyno tuning session, I maxed out the Walbro 255lph fuel pump around 25psi. The car had more to give, but the pump was the limitation. Enter the Walbro 400lph pump! This pump should give me the fuel pressure I need at higher boost levels without requiring a secondary, in-line fuel pump. The installation seems pretty straight forward, especially since I already have a Walbro pump installed. I’m hoping that the wires and plugs match up, meaning that this can be a 10 minute swap. Here is a good writeup on installing the Walbro in an S14. This is a nice video for installing the pump in a 240sx as well (it’s part 1 of 2).

New Nitto NT01 Tires

New Nitto NT01 Tires
New set of Nitto NT01 tires for the track season

My new tires finally arrived! I ordered a set of Nitto NT01 tires for the 240sx in hopes that this will be a step up from the Dunlop Star Spec tires for my track days this summer. the Dunlop’s were great for Auto-X, but they fell short on the track in my opinion. I’m not quite ready for racing compounds, but I feel that this is a step in that direction. Perhaps next year I’ll get a second set of wheels to swap at the track like most of the other guys do?

I’m going to remove my wheels and have these mounted tomorrow. I don’t want anybody using an impact wrench to tighten my lugs! =)

Next Project is A/C

For my next project I will be reinstalling A/C in the car. After the RB20DET swap went awry, I disconnected the entire A/C and sold off the motor set. I sourced an RB25DET compressor and mounting bracket from RAW Brokerage. My lines are already modified to work with an RB20DET compressor, but they are slightly different (appear to be backwards). So I’m going mock up the new lines with the help of a local shop once the compressor and condenser are in place. I’m shooting for a custom discrete A/C line look. The engine bay is crowded enough with my ABS module.

I’ll be sure to snap some photos and explain the basics. It seems to be a fairly straight forward process if you have somebody that can modify the lines. We’ll see…..

New Wiring Harness

For the past week I’ve been working on replacing my upper and lower wiring harnesses. While my original harness worked, there were a few items that I wanted to tidy up, and I always had a slight random hiccup with the vehicle. I could never determine if that was because of the AEM EMS not cooperating with my CAS wheel or if there was an electrical gremlin due to the hack job from an auto-5spd RB20 and then the RB25 swap.

I purchased a wiring harness with the ABS sub-harness and Auto->5spd from Wiring Specialties through RAW Brokerage. The harness arrived with an instruction manual, and it was super clean. All original plugs and wires, properly loomed, and basically ready to install.

They say this is a 15 minute job, and I think if you’ve done it a few times before then it quite possibly is a 15 minute job. My situation was a little different…

First I had to remove the original harness, which took longer than I had hoped, but that was simply because I was paying attention to where things were plugged in so that the install would be a bit easier. The original harness came off in about 30 minutes for me. pulling it through the firewall was surprisingly easy.

The new harness was a little more difficult. Various forums/posts on the internet suggest having two people work the harness plugs through the firewall and I can see why. That would have probably saved me 10-15 minutes easily because I had to keep going back and forth from under the dash to the engine bay to work the harness through. Where I started to run into trouble was matching up the plugs. Some of my OEM plugs have been removed, cut, spliced, changed, etc. and it wasn’t a direct fit. I expected this, and while I probably pestered RAW Brokerage, Wiring Specialties, and the various forums on the internet more than they would have liked, in the end we figured it out.



A quick list of my troubles:

  1. My OEM Oil Pressure Sensor used a different plug than the one provided. I probably don’t have the factory RB sensor. I just re-pinned the proper plug for the solution here.
  2. My ABS power plug was hidden in the wheel well and wasn’t where it should have been. It took me awhile to find this.
  3. My clutch switch (or Park/Neutral sensor)  was cut/removed and connected together so the vehicle would start after the auto to 5spd swap. I need to get a new plug for this to finish cleaning up.
  4. My S14 wiper amp is missing and I’ve been rolling with an R33 wiper amp for the past few years. I’m sourcing an S14 wiper amp just to be proper here.
  5. My fuel injectors are not OEM and I never knew that my injector subharness has been custom since day 1. The plugs didn’t match so I used my original harness here (It’s in fine shape).

Despite my few dilemmas here, the car is in surprisingly good shape having gone through 3 engines.


Here is the difference between my injector subharness plugs (Tomei plugs for Denso Injectors) and the OEM.

Wiring Specialties uses quality parts. Here is the main ECU plug.

New Harness

Old Harness

If you’re considering doing a swap and aren’t an electrical genius, do yourself a favor and buy the harness. You might also consider picking up a patch connector for the harness. It goes between the harness plug and the ECU (in my case the AEM EMS). You just find the wires you want to tap into and do it on the patch connector so you don’t damage your harness wiring in things like a boost solenoid or AFR sensor. It also lets you move your standalone a little further out of the way so it’s not right under your feet on the passenger side.