DarryCar

Well I started running out of fuel on high boost, so it was time for an upgrade. I went from the Walbro 255 to the new Walbro 400. I could not find any write ups on how to install this fuel pump into an EK and I had heard talks of having to do modifications due to the larger bottom end of the 400. I decided to tackle this project, take some pictures, and do a write up for those interested in running this pump. Wasn't quite sure what I was in for when I started, but it turned out to be pretty simple. So here it is for your viewing pleasure......

So, here is the monster. The big, bad Walbro 400lph. Let's see what it can do.


Just like any Civic fuel pump, you got to get to it under the rear seat cushion


The red and black wires you see coming out of the cover are upgraded 10 gauge wires for the fuel pump and inline relay. A must do upgrade when putting a lot of demand on the fuel pump. Take the four screws out to lift the cover and access the fuel pump and sending unit.


Unplug the fuel pump and take both fuel lines off.


Remove the 6 10mm nuts and pull out the fuel pump unit. Ah, there is the 255 that has served me well for the past four years.


Unclamp the hose on top of the old pump and remove the pump from the bracket. Should be a tight fit, but it will come out. *Caution* Remove the plug for the power and ground BEFORE removing the pump from the bracket. If it is still plugged in, you run the risk of tearing the wires and connector right off and with have to do some wire repairs. I didn't do it on this one, but I have done it before.


Here you can see some of the differences in of the 255 vs. the 400. Physically the bottom is bigger on the 400 then the 255. I think this is where the rumors are coming from that a bit of modification has to be done to get it to fit. As you will see later, this is not the case.



Here are the differences to the top of the pumps. As you can see, unlike the 255, the 400 is not a "plug and play." Not only will the stock connector not plug in, but the power and ground terminals are on the opposite sides of the pump on the 400 as opposed to the 255.



There are instal kits out there that you can get for this pump. I am not sure if will allow you to plug in the stock connector or not. I opted to not get the instal kit and just figure it out. Pretty simple though, just de-pin the 2 wires from the stock fuel pump connector. The pins will actually plug right onto the 400, but again the terminals are on opposite sides.


Wires connected to the 400.


The ground wire is screwed onto the pump assembly bracket on the right side of the pump. The plug connector on the top (outside) of the fuel pump assembly has power and ground pins. The power wire continues all the way down to the pump, but the ground pin goes strait to the pump assembly/bracket.

Top side of pump assembly (shitty pic)


Underside of pump assembly/bracket where the power wire comes through down to the pump.


Not sure how they did it, but the screw stripped out on me when I tried to take it off. So I cut it off.



I decided why not beef up the ground strap. Couldn't hurt, so I used 10 gauge on that as well. There are 2 little holes on the fuel pump bracket just left of the fuel pump. I used a self tapping screw and secured the new ground strap to the bracket on the left side of the pump.


Pic of self tapping screw and ground strap.


Power side of wiring now on the left side of pump.


Wiring complete


Once the wiring was finished, it was time to move on to the next part that needed to be modified. The rubber grommet at the bottom of the fuel pump holds the pump into the fuel pump assembly/bracket along with the hose and hose clamp at the top of the pump. Because the bottom of the 400 is significantly larger than the 255 (and because a new rubber grommet was not provided), I modified the stock grommet to make it fit onto the 400 while still being able to fit into the bracket and hold the pump.

Stock rubber grommet on the 400.



In the bracket


As you can see, the grommet will go back into the bracket just fine, but does not sit on the bottom of the 400 squarely. Now you can just shove it back in and I am sure it may hold, but I decided to get it to fit a little better. All it took was a Dremel and a pair of dikes.

Top side of stock grommet. Notches in the rubber that held the 255 in place.


Used the Dremel to elongate those notches to better fit the bottom of the 400. Again, shitty pic I know.


I wasn't sure what these ports were on the bottom side of the 400, but when I blew into the inlet side of the pump, air would come out of these ports. I thought it might be important, so I cut a piece out of the grommet to accommodate for the ports.

Ports on the bottom left side (I know, I know)



Grommet notched for ports.



A little extra cut here and a little finesse there, and your in business.


As you can see, once the 400 is in place on the bracket, there is no clearance issues with the bottom of the pump being larger.




Just put the outlet side on the hose, and push the pump downward into the grommet and base of the bracket, tighten the hose clamp, and BAM! Done like dinner.


Couple of extras: I figured I would replace the fuel pump sock while I was in there. The one I took out was at least 13 years old. It looked like it was about time. Thanks Checker's (sorry, O'Reilly's).


This is the seal or rubber gasket for the fuel pump assembly. I must not have payed much attention to it when I installed the 255. Be careful when installing the fuel pump assembly not to get this gasket folded or caught on the studs that hold down the assembly.



It never leaked on me, but I figured why not get a new one.


Ready to go back in. Never to be seen again.


Good buy Walbro 400lph. Make us proud!


Install is the opposite of removal. Just be careful and take your time. Make sure the sock is positioned correctly in the tank and you do not fold up the gasket. Leave the cover off and turn the key on to position #2 to check for correct wiring. You should hear the pump prime up. Do that a couple of times to prime up the fuel system. Start the car and check for any leaks. Once you are content with your work, put the cover and seat cushion back on.

Now I have read that the sock and the position of the Walbro 400 makes the reading on your fuel gauge wrong. Supposedly you will run out of fuel when your gauge still reads a half of a 1/4 tank. I don't know if this is true or even possible. The pump, sock, whole assembly sits in the exact same position as before. There should not be any fuel gauge issues that come about from this instal. Anyways, with any vehicle running boost, you should never let your fuel tank get anywhere close to being on the empty side.

As with any instal or modifications, please be safe. I am not taking any responsibility for anyone attempting this project. Don't smoke or have open flames around the fuel system. Keep the drop lights far away from the fuel tank once it is open. And if your going to drink, well I've said my peace.

Hope this helps people out there. I know I had a few of my questions answered and a few myths busted while attempting this install.

Now it's off to a dyne session I go............

LocoJoe

Nice write. Will be installing my 400 soon.

met

Awesome! Thanks for posting this up! Now, I really want to know what before and after hp numbers are.

TheShodan

iTrader: (14)

Great write up indeed.. Way to go!!

Westrock2000

Does this one whine even more then a standard whinebro?

Turbo-LS

iTrader: (4)

OP excellent write up !

I must have a " special" walbro pump because mine doesn't make any noise and I'm always seeing people omplain about theirs whining??

DarryCar

From what I had read before the install, the 400 is supposed to be quieter then the 255. I never had any complaints with my 255 concerning noise. Maybe I just got a quiet pump. The 400 seems to make about the same amount of noise. The only time I hear it is when I turn the key to position #2 and it primes up. That noise I want to hear every time.

DarryCar

HP numbers where a little disappointing for me, but this pump has A LOT of potential and room to play.

I got my car tuned at the end of last March (in Arizona) when the ambient temps where in the high 80s, low 90's. Running E85 and with the Walbro 255and 1000cc injectors, I got 520whp on the dyno. The tune was great and the car ran like a bat out of hell. When summer came around I decided to get into a wire tuck project. I didn't have my car back together and running until December. Now in December with the cooler air temps (low 60s, high 70's) my duty cycle would max out at 100% around 6000RPM on full boost. The cooler denser air was maxing out my fuel pump. Hence the need to move to the 400.

With the 400 installed, we were able to move the base fuel press from 38psi all the way up to 60psi. We had this thing dumping so much fuel, that it would misfire in the higher RPMs due to it drowning out the spark. That's what I was looking for. Unfortunately they really cut the fuel here in the winter and the E85 that I got at the pump was only rated at 70% ethanol. Catch 22, cooler air during the winter, but lower grade of fuel. We did not feel comfortable pushing the tune on 70% ethanol, so we only got 507whp @ 25psi.

Once the fuel changes in a couple months I should see a little more power gains. Like I said, there is a lot of potential with this pump. On race fuels and some bigger injectors, your going to see some big power gains.

SPOOLINmatt

nice, but damn with the blurr lol

LightningTeg

Theres probably a setting on the camera for "macro" which allows for close up shots.

DarryCar

Here are some numbers and graphs. The last run I believe is the dark blue line.

shanebadoo

x2 Was politely going to say the same thing. Thanks for the write up. Good stuff

mrbsponge

Judging by you lambda on your dyno graph youre not drowning the car out. .84 is about an 11.80 & a lambda gauge does the conversion already. If anything I woulda tried a tad more fuel & took better advantage of the exh energy of the ethanol. Looks like the graph is uber shakey up top

DarryCar

Ya, unfortunately the screen on the camera I was using is damaged so I could not see what I was taking a picture of. Next time I will use the phone camera. Thanks for the responses though. Glad to hear people are interested in this.

DarryCar

I really thought we were going to pull some better numbers out of it this time. My last tune with the Walbro 255 we got 520whp @ 26psi, but that was with a better grade of E85. I think my tuner just wanted to keep it on the "safe" side especially with the 70% ethanol. Hopefully when the fuel changes I will see some improvements.

00_EKHatch

Thanks for the writeup, I am currently running the 255 and it has been really good to me. Glad to see if I need more fuel I have an awesome easy single in-tank pump option. And I really can imagine how much power this thing can handle on race gas. Since E85 requires so much more fuel usage, you could see big numbers on the stock line, and huge numbers on a full length braided line.

m3tech95

Not sure if this was mentioned, but if this isnt a daily driven car, I would look into buying E85 or even higher grades of Ethanol by the drum, you can look into organizing a group purchase with some local people in your area... The reason I decided not to run E85 was exactly that: the seasonal change in fuel grade and mixture and it varying from gas station to station.... its like gambling with your build. The upfront cost might hurt a bit, but nothing will cost you more over the long term than blowing up a perfectly good build trying to save $200-300.....you will recover the expense in the stability & consistency of fuel........great write-up BTW, a well needed step-by-step for all the 96-00 civic owners.

m3tech95

To ^ Ive heard of a few people that basically use the old sock from the Walbro 255 since the angle is better and the sock is longer.........hopefully someone can confirm this solved the fuel guage mis-read issue?

DarryCar

That's what I ended up doing was just using the sock off of the 255. Actually I just got a new one for the install and it is a stock Honda sock. It sits in the same position and I have not had any issues with the fuel gauge being wrong. I think that I have heard not to use the sock that comes with the install kit. At least not on the Hondas.

tron_

I like the writeup, could you draw a diagram or explain how you wired up the relay and ran the fuel pump wires? Atm I am running a 255 plugged into the stock harness and want to upgrade to the Walbro 400 and think it might be a good idea to wire up an independant relay.

EsotericImage

iTrader: (8)

great write up


+1

DarryCar

There are a couple of write ups on how to hard wire the fuel pump and that explain it very well. I will do my best though as it is pretty simple.

Get yourself some 10 gauge wire (black & red), a 30 or 40 amp fuse (and fuse holder), a 4 pin 30 or 40 amp relay, and a connector that will go into the stock fuel pump plastic connector. I think I did 40 amp, but I don't remember.



Photo of schematic is for a Stealth or something, so don't worry about the wire colors. It just gives you an idea.

Off of the relay:
Pin 87 -10g to new fuse to battery
Pin 30 -10g power to fuel pump connector
Pin 86 -stock power wire that used to go into fuel pump connector
Pin 85 -10g to chasis ground

With this set up you may have to retune your vehicle for different fuel rail pressures as the fuel pump works differently at different current flows. This is a must though for higher horsepower applications due to the factory wiring not being able to flow enough current. Hope that helps.

tron_

PERFECT, thank you so much man!

ekb16

iTrader: (1)

you are golden man..i just bought this pump and there was no instructions or kit so i googled n found ur thread and it was exactly the info i was looking for..thanks alot..btw the fuel pump sock, can u get that at a auto parts store? cuz i dont think honda sells just the sock alone

DarryCar

^^Your welcome and thanks for the props. I did the same thing searching the web for install instructions and couldn't find anything. Glad this helped out. Your right, Honda only sells the sock with a new pump (bastards). I got mine from the guys at O'Rallys. Sure Auto Zone carries it to. It's a great pump, good luck.