Write-Up: Walbro 255 lph Fuel Pump - Series I

From what I've read, the 42.5 lb injectors are overkill until you're running smaller than a 3.2" pulley.

This is a supplement to this writeup. I finally put this thing in my 97 as well as replaced the fuel level sensor. This really really sucked to do for me so that's a warning I guess.

First off, here's the hole...





As you can see, it looks every bit as horrible as I feared.
I would say PBblaster is a must and a new lock ring ready to go.



old and new lock ring (gm calls it a locking cam for some reason)



Ok the fuel assembly is out so you can clearly see the tabs that hold the lock ring. Perhaps hours of waiting and more PBblaster would have broken that out but I ended up bending out those five tabs a little to help get it out, which I bent back into original position before I replaced the assembly. The usual screwdriver and hammer didn't do it for me. In that picture, you can also see the square-cut seal that seals the fuel assembly to the tank. Be careful not to drop that in the tank while fiddling the assembly in and out.

Now bare pump pics (oem vs walbro)

















That pic is how the factory pump is plumed. You can see it has the corrugated hose and then a seperate port for the venturi path, which has the little hard vinyl hose.

These pictures show how it needs to be set up with the walbro pump..







And now the ugly...



I was already pissed at how much of a pain it was getting the thing out of the tank but when this happened, I got the fevery "I'm fucked" feeling when I did this. I tried removing the hose from the oem pump gently. It just wasn't happening. So I'll say in addition to the lock ring, make sure you have a new hose for this thing if you didn't buy a brand new kit that has it. ZZP sells the currugated hose individually. Instead of waiting a couple days for a piece of slurpee straw, I went ahead and cut off the mangled end of my hose and forced it onto the pump. With the clamp on, it's tight and not stressed so it should be good but I still don't like it. As well the vinyl venturi hose gave me problems. It was slightly damaged coming off the old pump but I don't see any obvious way to remove that from its other end at the bottom of the strainer so I also had to just make it work. It went onto the fitting and stayed without much of a problem though.

That's the old and new fuel level sender.
That's a brainless fix once the pump's out. You just have to wire it.

First off thanks to palermocorey90, turtleman for this thread, info and pics. I am posting this to ask if when changing a fuel pump, would the area indicated in the pic below get scratched or damage in any way. The reason I ask is because my car stalled on me a few times on the way home on the weekend and had to have it towed. I thought about towing it home but I decided to tow it to a dealership instead. I am not the most patient guy and both palermocorey90, turtleman indicated that this job almost made them lose their cool. Of course I had thought that since I had never changed my fuel pump that I should probably change it soon and I intended to, but it failed before I had a chance. The point is, the dealership heavily scratched up my car in the red are indicated below and I can't understand what they were doing. I am currently having major issues with them in trying too get it fixed. They claim that they wouldn't have had to do anything with this area. But I had indicated to the Service Advisor that I had recently painted the car and was hoping that they would do anything they could to protect it.Any help here would be greatly appreciated guys, thanks!

The only reason they would need to be in the area of the fuel filler is to remove and replace some fuel.
Not absolutely necessary to do that unless your tank was full, but who knows.
Otherwise, all access for changing the pump is in the trunk.
Keep pressuring them to fix the paint.
I had mine in a body shop a few months back to replace my drivers side door and paint the left side of car and it came out with new scratches on the right rear quarter panel. They denied doing it but I kept on them and they finally fixed the right side.

Thanks for the support RickW, trying to get these guys to admit that they screwed up your car is like pulling teeth. Although they won't admit that they caused the scratches they said that they would buff it out. But I know that 90% of the scratches will appear gone to the naked eye but 10% will still show and the rest will return after ten washes. I am so pissed that my car when in there without a blemmish and after $1000 for the pump I end with paint damage!!!

Ask them to wet-sand then polish/buff the area. That'll take the scratches out.

If any of the scratches are down to the base metal, they will need repaint. Otherwise a wet sand and buff/polish will do the job.
That's what they did to mine. (wet sand, buff/polish)
I have some door dings on the passenger side that need repairing and have talked to them about fixing these in the near future and they agreed to sand, paint and clearcoat the area that they damaged at that time also.

How long do the stock pumps last? While I've got my carpet out I'm thinking about doing the fuel sending unit, and maybe the pump if there's a significant chance of it going (almost 90,000 miles on it). I won't be building up the engine any time soon, so I might as well stick with the stock pump for now if I can.

Jack the R wrote:

How long do the stock pumps last? While I've got my carpet out I'm thinking about doing the fuel sending unit, and maybe the pump if there's a significant chance of it going (almost 90,000 miles on it). I won't be building up the engine any time soon, so I might as well stick with the stock pump for now if I can.

My stock pump was working fine at ~185,000mi when i switched to the walbro. The strainers were not clogged either. At that point the part that had failed was the fuel level sensor, which I think was bad since I got the car at 140 or 150k

Mine was out at 83,000 (fuel level sensor). I bet it had been out by a long time by then.

I don't recall AA mentioning a pump failure. Or many others for that matter. Unless anyone objects I'm going to treat it as a reliable part and just do the fuel level sensor. Wouldn't mind getting a couple spare strainers though just for the heck of it. I'm sure they're too cheap not to have a couple sitting around.

For what its worth Jack, mine failed at 210,000K. The symptom I encountered just before it failed, was that the engine would cut out while coasting, but putting the car in neutral and re-starting got me back in drive. It did that two times before it failed the third time. I attributed the first two times to the weather as the stalls occured in the winter. I was planning to replace the fuel pump at the beginning of the spring, just before it died on me, but I didn't get around to it in time. Even though yours might have some life in it, I would replace it at the same time.

If they weren't so bloody expensive I'd be inclined to agree with BMD and do it for preventive maintenance.
But if it's not showing any signs of failure I would give it some more miles.
But hell if you got the cash put in a new one while your there. I wouldn't want to be the reason you got stranded on a cold dark night sometime this winter.
I wouldn't bother with extra strainers either. Do you really think you'll pull the pump sometime in the near future to replace just a strainer. I don't think so.
The next time your in there will be to put in a new fuel pump and strainer hopefully before it completely fails on you.
As has already been mentioned they usually give you some notice before complete failure. Not always though.!!!!!!!

It's getting to be new computer time again, so I don't want to replace the fuel pump unless it's going to die within 20,000 miles. Seems unlikely based on what I'm reading. Thanks everyone.

I got around to replacing my Walbro pump with the Racetronix pump today so here's a write-up supplement. After having to do a lot of research and comparison without being able to look at the inside of my stock pump assembly, I made sure to take lots of pictures of it this time.



there's the complete internal harness after I pinned in a new level sensor and the new Racetronix fuel pump harness (it comes with a connector that fits the W-bodies so you can't use it on a riv)


there's the bucket off my stock assembly (obviously removed from the top)

there's the piece that the venturi line feeds. This part sits directly atop the strainer sock on the bottom of the bucket...

...which is pictured below





there's the top part of the assembly pretty much naked


that's how the pump itself looks fully seated at the bottom


there's the racetronix getting put in


That's the barbed fitting that the main corrugated feed hose slips onto. Reusing this corrugated hose is not an option unless you want to hack it up with clamps. It can be bought from the vendors. My racetronix pump came with it.




That's how it'll look plummed, just like stock.
The plastic venturi feed line didn't fit tightly onto the new pump fitting after it had been beat up from being twice removed and unfortunately It's not as easily replacable as the main hose so I nipped off the end of it and with a fresh end, it fit tightly onto the pump fitting and there is more than enough length on it to cut that ~3/4" of it off.






and there it is reassembled and ready to go back in

Getting the locking ring off was a piece of cake after doing this already several months ago so I'll definitely say it was a very good idea to use antiseize or something on the locking ring. I used petrolium jelly.

btw I used the level sensor off a new 98-00 gtp pump assembly (Delphi part) and it looks and works fine. Use your original float obviously.

I did test this afterwards to make sure my fuel pressure issue was corrected. The pump does, in fact, retain fuel pressure when it's not running now. I hooked up my fuel pressure gauge at the rail fitting and turned the igition on, watched the fuel pressure come, then once the pump ended its prime cycle and shut off, pressure stayed, instead of immediately bleeding off like it was with the walbro and its rigged venturi setup.

That bleeding off of fuel pressure is not harmful in any way except that it makes starts a little less natural and effortless. This is a bigger problem for me than most people because I wait until after the prime cycle to start the engine so my electronic boost gauge can calibrate itsself. If you have a walbro and start the car while its still in its prime cycle, which is what most people naturally do rather than wait, it's not really too noticable.

Thanks for the extra photos and advice about the corrugated hose. Do all walbros do this? Is that why you switched to the racetronix pump?

deekster_caddy wrote:

Do all walbros do this? Is that why you switched to the racetronix pump?

yes and yes

bouth pictures of the bumps still don't look the same as i had in my 96 :S....did they all have diferent bumps??

Neither one of these write ups pertain to the series 1. I dont know how Palermo cory ever got it to work but the pumps are not even close.I ordered the exact same pump that palermo ordered and It cannot fit and will not fit.in any way.
maybe I'm missing something but the new pump has nowhere to moore inside the pump housing.it will just knock about and bash the inside of the housing.
If any one with a series one has managed to get this to work,please let me know how its done.por favor!

... I made a Delrin sleeve for mine to fit....I also ordered the venturi specific one from intense, but then discovered I dint need a venturi, and had to plug it. did I ever post pics? if not I'll have to look for them.

a delrin sleeve? this I gotta see...
How did you modify the walbro to adapt to the oem housing bottom feed hole? I dont see any other way to modify it?If I put my ear to the grindstone I would come up with something but...I'm looking for a quick forMuLA!!!!!!!!!1

Here are a few pics of what I see as a Good mod.I got this one from Intense,$99 bucks.After seeing the oem set up,there is no doubt in my mind that the only fuel set up is a race one.The oem peripherals only make servicing the fuel system harder than it has to be.and pretty weak too!
everyone knows how to remove the oem pump so I wont cover that.

side by side

I cut a slit onto the bottom of the pump.I dont want the filter scruntched up in the bottom of the sump like the oem.It was the point of failure with the original filter.--

Walbro pump --

pump in sump--

side view of pump in sump--

cut 2 slits in side of sump for a circle clamp--

pump in sump all snugged up.not to tight or you will distort the housing.it is necessary to tap lightly with a hammer the circle clamp to flatten it against the outside of the sump.otherwise you will have difficulty inserting into tank.--

how pump looks from inside


Lop the top off the housing to make room for the walbro-


view of the level sensor thingie--


and here she is all snugged up and ready to pump--



after taking her for a test ride,I noticed a huge increase in throttle response.She gained a few HPs for sure.there was a big lull going hard round a corner.this told me that maybe the bottom slit that I cut for the walbro filter was a little too large and fuel sloshed out the bottom leaving the pump starved momentarily.but I am at less than a 1/4 tank so....
electrical hook up was a snap.the pump came with a pigtail that hooked right up the the oem connections.
its a real hassle working with a system that is designed by GM not to be fucked with.a good reason why a race tank is in order.I'll be converting the oem tank into a race tank with AE fitting in the future.I'll have access to the oem service locations but with the conveniance and serviceability of a race set up.

the reason why I did not use the original pump location in the sump for the walbro is because moving the walbro over a little,I cleared a couple of protrusions on the bottom of the sump that would have the walbro sitting higher in the sump than I would have liked.sitting lower the pump sits in more fuel for those low fuel situations.
For the series 1 folks,when ordering the L67 pump from intense,specify a "Non Venturi" type pump.the venturi style pump has a little brass tit on top of the pump that for the series 1 is unessecary

Right I found my pics. Not all of them as some were corrupt.

Pump with new Delrin Sleeve compared to stock pump:


Sleeve slid on: (I haven't plugged the venturi port yet in this pic. SERIES ONE DON'T BUY A VENTURI SPECIFIC ONE!)


More of the sleeve:


I made a tool to pull the new hose onto the barb since it was REALLY REALLY tight:


Attachments with fuel clamps:



Whole assembly:



Thats all I got. As I said a bunch of pics were corrupted. Mine does sit right at the bottom of the container with no issues. The Delrin sleeve slides right against the stock location, and inside that the new pump sits inside its rubber sleeve to absorb vibration. I've run the tank practically dry with this setup with no issues. It performs as stock but with the Walbro pump.


Robo, your cornering prob might be because I *think* the fuel feed on ours also sends some down the 3 rods that have springs around them to keep the canister full. Its our version of the venturi that keeps the canister full on later models. (but I might be wrong, it was ages ago I took this thing apart.)