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Bottleneck fix w/ pictures

72K views 66 replies 34 participants last post by  kprah23 
#1 · (Edited)
I’ve been asked a lot for help on performing the bottleneck fix and setup a canister for a return line. I recently got a canister from someone that already had the bottleneck fix done and a bulkhead for a return line. The problem was the return didn’t go to the canister and the feed line wasn’t long enough for the pump to seat. Since they sent me their stock canister I decided to redo the entire setup so it was done properly. I decided to take pictures as I did it so maybe some others can benefit.

Here we have the stock canister.


The first step is to unplug the pump and fuel level sensor. Below is a shot of the plug. Next you’ll need to remove the wires.


To remove the wires, flip the plug over and push the green locking part out the front. You can see it just in front of the screwdriver below.


Push the locking part up to unlock it, and it will look like this.


With the locking part removed, you can see the connectors on the wires and the tabs that hold the in place.


Now would be a good time to mark the positive and negative wires on the connector for them pump. The wires for the fuel level sensor don’t matter.


Using a screwdriver, GENTLY pry up on the tab. While doing so, pull the wire out the back of the connector.


With all four wires out of the connector you can now remove the fuel level sensor. Use a screwdriver and pry the canister where it is holding the level sensor in.


Next let’s remove the canister. There are three tabs that lock this in place. You’ll want to be very careful here so you don’t crack the canister. I use a screwdriver and push it under the canister and gently pull the canister down. Do this on all three tabs. Be patient, you may pop one back on as you try the next one. You’ll eventually get it. This is the order I do it in.






You have now exposed the fuel pump. In the image below you can see the bottleneck. It is where the piece off the pump goes into the silver ring.


To get the pump out, push the rubber seal in the image below up from the bottom and pull it off the wires. Then pull the pump out.


Here is a view of the top of the canister. You can remove the black rubber part and discard it, we won’t be using it.


Now you’ll need to remove the metal ring. I use a Dremel with a cutoff wheel and cut the side and bottom of the metal ring. Below you can see the ring and seal. Throw those away, we won’t be using them.


Next step is to create a hole for the feed line to pass through. I use a Dremel for this, but a drill will work. Be careful though, the plastic can be very brittle and crack easily. Below is where I started the hole.


Now that you’ve got the hole started, it is time to split the top of the canister off the part that goes in the hole on the fuel tank. This is a two-step process. First you need to compress the spring and lift plastic washer. Using a needle-nose pliers pull that washer out. It is split on the other side of the flat tab, so it will come off with a bit of force.


Now flip the top over and stick a screwdriver into the hole and pull towards the middle of the canister top. While doing so rotate the top down to disconnect the two parts.


Here is the result of the previous step. Now all you have to do is pull the canister top back and out.


Now cut a bit of the part of the feed off to make sure it won’t poke through the hole and hit your fuel line.


Here you can see the line going through the canister top. Make a note of this or draw around it with a marker because the next step is to drill for the bulkhead fitting.


Here is the bulkhead installed with a stat-o-seal. As you can see I had to remove some of the material to make room for the stat-o-seal.


Here is the top with the bulkhead and stat-o-seal.


Here you can see where I installed the bulkhead for the return line. Putting it here will allow for a straight shot through the top of the canister. No looping is necessary. Notice I had to remove some support material to make room for the stat-o-seal and bulkhead nut.


Top view of the feed and return bulkheads.


Both holes of the canister top.


Here is a view of the lines installed from the bottom of the canister top. The feed hose should extend down about 2.25 inches from the canister’s top. More on this later.


Now it is time to remove the bottleneck from the pump. There are two locking tabs on there, pry them up with a screwdriver and pull the piece off.


Now you need to remove the part that holds the bottleneck on. It is split so just insert a screwdriver and twist.


Here is the pump completely disassembled.
 
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#2 · (Edited)
Here are two different types of clamps, use the type on the right, NOT the worm gear style. These are called "fuel injection clamps". Most any parts store will have them, or you can get the Summit, Jegs, etc.


Now it is time to remove the sock from the canister. There are two locking tabs, one on each side. Carefully pry them up and remove the sock.


Now put your pump on and test fit. Make sure that the pump seats in the bottom of the canister. If it is too hard, remove the pump and cut a small amount off the feed line and try again. You want to be absolutely sure your pump seats all the way in the bottom of the canister. The proper seat is shown below. Normally there is an X in the opening, but the one I got here was broken.


In this image I am showing a piece of 1/2 inch copper pipe that I've cut to length and slid over the fuel line. This will help to keep the pump in place. I take a dremel and grind from the inside of the pipe at both ends to make sure it is smooth and will not cut the hose as I slide it on. The copper pipe is not necessary, but it assures the pump will not move and doing it this way you don't have to drill holes and deal with zip ties.


Now it is time to seal off the fuel pump unit. This shot shows the feed and return ports. The feed is the circle in the middle and the return is the rectangle on the left. You’ll need to make sure to seal both of these.


There are several ways to do this, I prefer to use a plastic welder and weld them closed. Other people use freeze plugs, or some other type of sealant. I have a cut off fuel tank that I then install pump unit into and test for leaks by filling the tank with water and making sure no leaks are present.


Now just put everything back together and hook your lines up. If you have any questions just let me know.
 
#4 ·
#8 ·
Great wtite up man. We appreciate it.

The fuel injection clamp is for the black fuel line that goes to the top fitting correct?

Is that line E85 friendly?

How much does this cost, roughly?
 
#9 ·
The clamps go on the line going from the pump to the bulkhead. I also put one on the return. It is entirely not necessary there.

The line in the pictures was garbage. I could see cracks when I would bend it. I had Tyler get some of the Gates Submersible hose. It is pretty expensive but it is made to be under fuel.

Price varies on where you get your parts.
 
#13 ·
awesome write up!

Those fuel injection clamps are awesome! Use them on every vacuum line, great for solving those pin hole leaks with the soapy water you just can't seem to fix.
 
#15 ·
There were a few lines that were too small like the wastegate but they work great on the pcv, brake booster, and the other one on the tb
 
#23 ·
I want to do the BNF when I install my new fuel pump soon. However, I'm not going to be doing a return line at this point. Given this, I don't want/need those blue earl threaded fittings. What's the process for doing the BNF, but keeping the stock feed line?
 
#24 ·
I recommend NOT using the copper pipe over the hose for the spoolboy mod. A few people have had the pipe rub through the hose. Many people have just used the hose to hold the pump in place with no issues. I used a worm clamp around the pump, drilled a hole in the clamp and put a bolt through the canister/clamp to hold the pump in place.
 
#27 ·
Ok so I've read this whole thing, it looks like something that anyone with half a brain mechanically can do, and something that EVERYONE should do.

Personally, I put down 404whp on pump gas @23psi, and I have upgraded fuel mods accordingly. I honestly don't remember correcting this though, and with the amount of work involved I feel like I would remember it. If I'm not having any fuel issues with the car, would you recommend pulling the pump and doing this mod anyways? Is it something worth checking for to see if it's even done or not? Any input is appreciated!
 
#29 ·
how much harder while doing this instead of a 255 would it be to go ahead and install a 044 in?
 
#30 ·
This is the best write up for the BNF ive ever seen on here... great job. This might be a dumb question but returning fuel back into the canister with a surge tank, would this cause an issue? I know nothing about fuel related things but i want to do my setup my self so im just trying to understand everything before i take it on.
 
#35 ·
Is there I detailed how to on just a bottle neck fix? I'm putting a walbro 255 in my stage 3 car and all I want to do is install that with the bottle neck fix. I do not plan on doing a return and aftermarket fpr.

I've been searching for a good detailed how to on that but no luck.
 
#37 ·
Yes I have the stage 3 canister. But that's the very 1St I've herd of that after reading a ton on the Internet. I thought if your fuel needs to go threw the factory fpr then that's the bottle neck also combined with that little white cap in to of the walbro pump. It starts big then narrows right down and very restrictive.
 
#38 ·
Duster360 has a thread that shows how you can use an FPR out of a Corvette to accomplish your goal of using the stock lines. Search for Corvette FPR and you should find what you're looking for. Not my cup of tea, but it seems to work for people.
 
#39 ·
This mod was a giant pain in the ass.....and 100% worth it. Before, the bottleneck was starving my car on E85 and AFRs were far, far too lean. Now they are on point, and at a lower fuel pressure than stock! The car runs like a scalded dog with no knock. This setup will likely have enough fuel for big turbo once I'm ready to do that.

Thanks for a great write-up!
 
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