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Nitto1320 M O D
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Discussion Starter · #1 ·
I just sucessfully installed a Walbro 255 on a 99 S10... it wasn't meant to be, but with a few little tricks I got it done.

Started off by removing the bed (sand blasted and painted my frame once I saw what was under there, lol)

Pull the 3 lines off the stock pump/sending unit, unhook the 2 electical connectors

Remove the snap ring that holds the assembly in place (it might break depending on how old and rusty it is)

Give the pump assemble a little love and it will pop out (its spring loaded)

now to the dissassembly of the assembly that isnt supposed to be dissasembled

start by removing the black clip that is holding the sending unit component in place, once that is removed, remove the sending unit component and pull the wires out of there holders... You can try to get the wires out of the connection at the base, but i dont reccomend it, i just carefully let the sending component hang while I did the rest...

Pull the small plastic hose off of the pump (syphon tube I guess)(this will take some force, but dont break it)

The stock accordian hose needs to be cut of both ends (replaced later with a high-pressure fuel safe 5/16" rubber hose)

Pull the filter off of the bottom of the assembly.

Disconnect the electrical connection from the pump

Push the two tabs on the side of the assembly and remove the center plastic peice that actually contains the pump.

Pull the pump and its rubber keeper out of the plastic container (will take some love and jimmying)

Pull the filter off of the pump and remove the pump from the rubber keeper (once again, love and jimmying)

Place the new pump in the rubber keeper (look before you put the pump in the rubber kepper, it can only go one way so the filter hole will line up)

I dont know if this was just MY Walbro, but it didnt have the brass nipple for the syphon tube, so I had to pull it from my old pump and press it into the new one (it was a bitch.. I also used gas-safe sealer/adhesive just in case)

Place the pump and rubber keeper back into the plastic peice (it can only go one way via mounting tabs)... once placed put the new filter on the bottom of the pump.

This is a good time to put the rubber hose on the pump (the hose it comes with is not long enough, I ended up using about 10" of fuel safe 5/16" fuel injection hose) Tighten it down nice and snug.

Place the inside plastic peice with the pump assembly into the sending unit assembly and make sure you pull the black syphon hose through)

Slide the sending component back onto the assembly and replace the black clip and rehook the wires into their keepers.

Finagle and push and cuss and pry and what not to squeeze the syphon hose onto the nipple (it hits the rubber hose and clamp and it a really tight squeeze)

Clamp the top portion of the 5/16 hose onto the assembly.

Hook up the electrical connection with the included converter.

You should now have a new 255lph fuel pump/sending unit assembly ready installation

Put back into the tank, reapply the snap ring, hook up electrical connection, and 3 fuel lines.. make sure the ground on the back of the frame on the passenger side is tight, and see if she goes.

I did this all without the pictures or without the intention of doing a write up but I think my memory was good enough.
 

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Nitto1320 M O D
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1,612 Posts
Discussion Starter · #3 ·
thank you
 

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S-series abuser
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694 Posts
Good write up...the only thing that would have made it nicer was pics. This should be stickied so the same question doesnt come up every 5.76 mins.
 

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Mcfly Minis inc
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3,102 Posts
I used this How to on installing a Walbro 255 fuel pump into the GM fuel module. It worked great, the installation was long but not too hard. I took some pictures, so I combined this how to with my pictures, and some additional comments. See below.

I just sucessfully installed a Walbro 255 on a 99 S10... it wasn't meant to be, but with a few little tricks I got it done.
Started off by removing the bed (sand blasted and painted my frame once I saw what was under there, lol)
Pull the 3 lines off the stock pump/sending unit, unhook the 2 electical connectors
Remove the snap ring that holds the assembly in place (it might break depending on how old and rusty it is)
Give the pump assemble a little love and it will pop out (its spring loaded)
now to the dissassembly of the assembly that isnt supposed to be dissasembled
start by removing the black clip that is holding the sending unit component in place, once that is removed, remove the sending unit component and pull the wires out of there holders... You can try to get the wires out of the connection at the base, but i dont reccomend it, i just carefully let the sending component hang while I did the rest...
Pull the small plastic hose off of the pump (syphon tube I guess)(this will take some force, but dont break it) I was able to use a pair of needle nose pliers to get this off.
The stock accordian hose needs to be cut of both ends (replaced later with a high-pressure fuel safe 5/16" rubber hose)
Pull the filter off of the bottom of the assembly.This filter needs to be saved and reused because the Walbro only provides the filter for the pump, not the module.
Disconnect the electrical connection from the pump
Push the two tabs on the side of the assembly and remove the center plastic peice that actually contains the pump.
Pull the pump and its rubber keeper out of the plastic container (will take some love and jimmying)
Pull the filter off of the pump and remove the pump from the rubber keeper (once again, love and jimmying)
This is what you should have at this point


Place the new pump in the rubber keeper (look before you put the pump in the rubber kepper, it can only go one way so the filter hole will line up)I was unable to use the GM rubber keeper, so I used the one provided by Walbro.
I dont know if this was just MY Walbro, but it didnt have the brass nipple for the syphon tube, so I had to pull it from my old pump and press it into the new one (it was a bitch.. I also used gas-safe sealer/adhesive just in case)My Walbro was also missing the brass nipple, I had to do the same, and yes it is a bitch.


Place the pump and rubber keeper back into the plastic peice (it can only go one way via mounting tabs)... once placed put the new filter on the bottom of the pump.
This is a good time to put the rubber hose on the pump (the hose it comes with is not long enough, I ended up using about 10" of fuel safe 5/16" fuel injection hose) Tighten it down nice and snug.
Place the inside plastic peice with the pump assembly into the sending unit assembly and make sure you pull the black syphon hose through)
Slide the sending component back onto the assembly and replace the black clip and rehook the wires into their keepers.
Finagle and push and cuss and pry and what not to squeeze the syphon hose onto the nipple (it hits the rubber hose and clamp and it a really tight squeeze)It was a very tight squeeze, I ended up trimming some of the hose off under the hose clamp, this made enough room to get the small black tube on.

Clamp the top portion of the 5/16 hose onto the assembly.
Hook up the electrical connection with the included converter.
Black to Black, Red to Gray.

You should now have a new 255lph fuel pump/sending unit assembly ready installation


Put back into the tank, reapply the snap ring, hook up electrical connection, and 3 fuel lines.. make sure the ground on the back of the frame on the passenger side is tight, and see if she goes.
 

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The above is also a great writeup and the pics sure help. As far
as using a Walbro pump, here's one with the nipple and hose
already to go from Racetronics. It may make things a bit easier.
Though it's stated its for Firebirds, etc, I don't see why it couldn't
go right into the module like the Walbro does. Does anyone
out there see a prob with it going in as a replacement pump ?
I do admit it's very expensive, but Racetronics states they will
be coming out with a lower priced pump at a later date.

http://www.racetronix.com/RX-F99-FPKG-2.html

http://www.racetronix.com/product/RX-F99-FPKG-2/RX-F99-FPA.jpg
 

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One Bad Dude
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872 Posts
Make sure you use a hose that is not only rated for fuel, but that is also submergable. Its been awhile, but i think the hose numberis JR30 or something like that. Also, instead of shaving off some rubber on the 5/16 hose, just slide the 5/16 hose onto its nipple, then slide the siphon tube onto the little nipple and then use 1 hose clamp to secure the two tubes. That is what i did, and it works fine. Even when i had 90 psi from the fmu.LOL
 

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Mcfly Minis inc
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3,102 Posts
Update on my fuel pump installation. The truck shut off on the way into work this morning, I think that the pump went bad this could be due to me running the fuel level being too low too often and I guess the fuel in the tank helps cool the pump, so the pump may have overheated. Or the main hose from the pump to the top of the sending unit could have come off. I am going to have the truck towed home tonight, and I'll take a look at it then.
 

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Yea the fuel does keep the pump cool. I never let my
ride get below a 1/4-1/3 a tank. Just isn't worth the
hassle of changing out a pump due to me being a lazy
a$$ regarding gas stops.
 

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126 Posts
guhman2002 said:
Started off by removing the bed (sand blasted and painted my frame once I saw what was under there, lol)
.
couldnt help but notice there is nothing about takeing the fuel tank off of the truck...
ok nice job but for all you people new to sandblasting THIS CAUSES STATIC ELECTRICITY NEVER SANDBLAST WITH YOUR GAS TANK STILL ON! My nephew did this 6 years ago knowing how to use the sandblasting equipment very well but not knowing of its potential safety hazards.I came home from vacation with a hole it the side of my shop.
 

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Mcfly Minis inc
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3,102 Posts
bg's said:
Yea the fuel does keep the pump cool. I never let my
ride get below a 1/4-1/3 a tank. Just isn't worth the
hassle of changing out a pump due to me being a lazy
a$$ regarding gas stops.
well in my case it's a matter of having enough money to put fuel in the tank.:haha:
 

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1lowGMC said:
well in my case it's a matter of having enough money to put fuel in the tank.:haha:
Man I hear that. It just cost me 40.00 bucks to put 12.23
gals of gas in my ride this afternoon...I feel like everytime
I pull in the gas station, I'd better get ready for one of these
:bang:

What a fu**ing racket !
 

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Mcfly Minis inc
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3,102 Posts
OK, figured out my problem. The line can off from the fuel pump to the top of the sending unit. I replaced it with a new piece of line, and realy clamped it down. The hose clamp is in a tight spot, and it is hard to get at. I'll see how long it lasts now.
 

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One Bad Dude
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872 Posts
Yea the ridge along the top of the pump makes the clamp tough to get at it.

What i did was cut a small groove in it to get a screwdriver/nutdriver in there to tighten the clamp. That way you dont have to put your screwdriver at such an angle. I wish i had some pics to better explain myself, but i think i explained myself pretty good.


Is that the only fuel pump you have on the vehicle? Do you have a helper pump or anything?
 

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Mcfly Minis inc
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3,102 Posts
badnoma said:
Yea the ridge along the top of the pump makes the clamp tough to get at it.

What i did was cut a small groove in it to get a screwdriver/nutdriver in there to tighten the clamp. That way you dont have to put your screwdriver at such an angle. I wish i had some pics to better explain myself, but i think i explained myself pretty good.


Is that the only fuel pump you have on the vehicle? Do you have a helper pump or anything?
Ah nice idea, I didn't even think about notching that ring to gain access. Yeah that is the only pump on the truck. I guess it pumps more than the stock pump, and the regulator just throws the extra fuel back to the tank.
 

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where did u get ur pump at. and what part number?
 
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