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Gasoline is flammable. Don't smoke around it. Don't make sparks around it. I take no responsibility for anything that you do with this information. If you blow your self up, it will probably hurt if you're still alive. Don't be careless and you should be OK. I'm still around to write this page aren't I?
Ok, with that out of the way, lets discuss your options for upgrading your Neon fuel system for use over 200hp or for forced induction. The thing that most people run out to do is either A. stick on an external booster pump, or B. throw a Walbro 255lph pump in the stock module.
Want to know why both of these are bad ideas as-is?
This is a piece of 3/16" brake line with the stock fuel regulator/filter assy on it's left and the stock fuel pump outlet on the right.
If you choose option A or B, all of the fuel that your engine receives has to first make it through both of these tiny passages.
Do those holes look big enough to you?
Ok, now that I have you convinced that those are bad ideas, lets see what we can do to make things better.
The first obstacle to overcome is that fuel pump outlet. It's molded into the stock pump so that you can't easily remove it, but if you buy a 255lph Walbro, like one from APE, you can easily take this crap off:
and end up with this:
But that isn't the end of things. You still have to figure out how to get from a 5/16" hose barb, out of the module to the fuel line.
"How we gonna do that?"
First, take the stock module apart. You'll notice that I used 2 modules to make my 1 module. That was because I snagged a j-yard fresh module to "experiment" on before I tore up Dave's stock module, and then I didn't trust the sending unit on the j-yard special, since Dave found the whole module laying in a mud puddle. The brownish module is the j-yard one, and the white module is the stock one from his 97 ACR.
To get the module apart, you'll need some skill, the little tool that came with your Walbro 255lph kit:
and maybe some flat screwdrivers and a friend. Be careful not to break the little tabs. They can be quite brittle from living in fuel.
You will also have to disassemble the connector for the sending unit and pump and remove the red and black wires that lead to the pump from the connector.
Now we should discuss fuel hose for a sec, since we'll be using some. There are 2 grades of black rubber fuel line that I know of. The first grade is meant for your average carb or low pressure EFI system. Most of these hoses have a burst rating of ~45psi. Then there is a 2nd grade of rubber fuel hose, commonly called "Fuel Injection Hose". This stuff will take about 150psi before it bursts. Use it and nothing else on any EFI car that you don't want to burn to the ground. But of course, it can't be that simple. The hose clamps on this stuff have to be rather tight and have to STAY tight without cutting into the outer body of the hose. This requires a slightly different hose clamp style than the worm style that most people are familiar with. You will see plenty of pics of this type of hose clamp throughout this how-to.
Now that you've got the bottom of the module off, you should see this:
If you look at the area where the fuel pump meets the top of the canister, you will see a small metal ring that retains a rubber seal. The fuel pump's outlet fits inside this seal.
Pull the pump downward and out of the seal. Now unhook the wires from the fuel pump and remove it from the module. Take the top part of the module off of the canister lid by pressing the spring loaded fuel return stalk to the side and swiveling the top back. Once you get the tab on the return stalk free, simply wiggle the top and bottom parts and pull to the side. The top pivots in o-rings where it attaches to the canister lid.
Remember that rubber seal and it's metal retaining ring? Take them off. I cut a slot in mine with a dremel tool so that they would come off easily, but a flat screwdriver and more prying would have popped them free. Hindsight is 20/20. Here's a pic of my sliced parts:
Now that you've removed those parts, make 2 cuts with a dremel or similar to remove the boss on top of the lid where the fuel used to travel. Now take a drill and carefully drill a hole in the top of the canister lid where the seal used to be. Select a drill bit that *JUST* allows the 5/16" high pressure hose to slip through. You may want to drill the hole smaller than what you need, and then open it up to it's final size by turning a drill by hand with vice grips so that you have more control. That's how I did it. If your drill has a low speed, that might work well too. Following the same procedure, drill another hole the same size for a fuel return line. Your lid should look like this:
Now comes the part that took me the longest to figure out. If you put the bottom of the assy together now, the pump will not seal to the bottom screen/pickup properly because there is nothing to keep it pressed against the bottom of the canister. The fuel hose will just bend or slide up through the top of the lid. And that's no good. SOooooo after a lot of thinking I settled on this approach:
That's a 1.700" long piece of 1/2" copper plumbing tubing that I slid over the fuel hose and butted up against my clamp and the lid. It works PERFECTLY. Your length may differ depending on how wide your clamp is and how far down the hose you installed your clamp.
The copper tubing fits nicely in the recess where the rubber seal used to be AND fits perfectly against the clamp AND fits tightly on the hose so it won't be squirming around.
You will have to cut off the very end of the fuel supply nipple on the top of the module where it fits into the o-rings to pivot on the lid so that it doesn't run into your 5/16" fuel hose now. You can see what I mean in this pic:
You can also see that we're going to drill some holes in the top of the module. Drill them with a 27/64" drill and tap the holes for 1/4" NPT. The places I have marked to drill will work, but you may want to move your "IN" to the new location that I note on the pic so that your fuel filter/reg will clear more easily without chopping on it.
Now that you've got your holes, find some male and femal 5/16" hose barb x 1/4" NPT brass fittings. The ones like I used with the small plastic collars are better and less prone to leakage. While you're at the hardware store, find some washers that the threads on your male 1/4" NPT fitting will *just* fit through. Then make a stop at the auto parts store for some 1/2" ID fuel hose. You only need about an inch of the hose.
Now take the fuel hose and cut a thin slice of it off to make a washer. Do this twice. About 1/8" thick is pretty good.
You will see in the next picture how the fittings go together to make the bulkhead style connections.
BE SURE TO USE 4 OR 5 LAYERS OF TEFLON THREAD TAPE ON THE THREADS ON YOUR BRASS FITTINGS.
ALSO BE SURE TO CAREFULLY OPEN UP THE PASSAGES IN YOUR BRASS BARB FITTINGS WITH A 1/4" DRILL (OR LARGER), ESPECIALLY THE RETURN AND ANY FITTING ON THE FUEL RAIL. IF YOU DON'T, YOUR MINIMUM FUEL PRESSURE WILL BE ~40psi BECAUSE OF THE RESTRICTION IMPOSED BY THE BRASS FITTING.
Screw the male thread fitting in from the inside until you run out of threads so that you have male threads sticking out of the module. Then wrap those threads with teflon tape. Then slip on your rubber "washer" followed by your regular steel washer and the female thread fitting. Hold the inner fitting still while you tighten the outer fitting down TIGHT until you see the rubber washer squishing against the module top. Just be sure not to go TOO tight and crack your module.This is what it should look like when you're done:
Now stick the stock fuel regulator/filter thing back in if you removed it, and cap it off like the above pic. Hold the cap on with a hose clamp. There will obviously not be any pressure coming out of here anymore, so the cap doesn't need to be high pressure and neither does the clamp. You can see what I meant by finding a better location for the return fitting....
Hook the top and the lid back together. Now run a short section of 5/16" hose from the "IN" or return barb back through your canister lid through the 2nd hole that you drilled and install a 5/16" brass "tee" in this line with the open end of the "tee" pointing at the top of the gas tank. If you don't do this, the canister will fill up and become pressurized, causing your minimum fuel pressure to be ~40psi or more. Plus I'm sure that it's not good to pressurize the canister. Hook your supply line up to the barb on the back of the module top. Secure both hoses to the bulkhead fittings with hi pressure clamps.
Now make sure that the fuel pump is turned properly and slip the bottom of the canister back onto the assembly and reassemble the connector and plug it into the bottom of the module top.
Now cut about 8" of fuel hose for each barb and install it with a clamp
Since you bypassed the stock fuel filter, you are going to need to add your own. I used a WIX 33321 filter that was originally for a 2.2/2.5 turbo car. Ask for one for a Shelby Charger w/turbo/efi if they have to know "What car?". It mounts where the fuel accumulator used to by simply drilling 1 hole and re-using the accumulator mounting screw. The fuel accumulator for this car is in the trash.
Hook up your fuel lines as shown:
To complete this system you can either install a fuel pressure regulator here under the car by teeing into the supply line as it comes out of the filter, OR preferrably by running a return line out of the fuel rail, then to an engine bay mounted regulator, and back to the tank like we did. We used another stock Neon fuel supply line as a return. It was about $25 from the local dealer.
Run the fuel line next to the stock one and secure it with zip ties to the other lines like this:
I chose to bend the line some and run it across the k-frame along the power steering rack and up the driver's side firewall so that it ends near the master cylinder.
You can see it if you look hard at the front of this pic
A lot of people like to take the easy way out and run their return from the schrader valve on the fuel rail. All you need is a AN-4 femal fitting on your return hose to screw onto the shrader valve. You have to remove the valve core before you screw on the line. Not wanting to be flow limited by the tiny hole left where the valve core was, I drilled a hole in the end of the stock fuel rail and tapped it 3/8" NPT (not much material for threads). I then soldered a 3/8" NPT to 1/4" NPT brass bushing into the end of the rail. I screwed a 5/16" hose X 1/4" NPT barb into the rail and ran EFI hose to the Cartech 2007 rising rate regulator and then from there to the metal return line. I painted the brass fittings black on the rail, so they may be hard to see in this pic:
Now for the bonus material:
Walbro 255lph in-tank pumps come in 2 different styles: Low pressure and Hi pressure. The only difference is the spring stiffness in their internal bypasses. The Low pressure pumps start to open @60psi, the Hi pressure versions bypass fuel @80psi. Here is a pic of a bypass circuit from a stock Neon Walbro pump. It is very similar to the 255lph bypass circuits in components and function, but it is located in a different place.
This circuit is in a different place on a 255lph pump. You can see it in this picture:
If you are using a rising rate regulator and/or running very much boost, your fuel pressure could easily eclipse 80psi, so we can't be having that shit.
So, here is the fix that I pioneered. I've used it on 255 in tank pumps in 3 cars now and it works great. BUT that bypass is there for a reason. It takes the load off of your pump before it can be overworked and overheat. Expect your pump life to be shortened if you run high fuel pressures all the time. If you use a system where the fuel pressure rises under boost, you will be running around 95% of the time at near stock pressure and only experience these high pressures @ WOT and under boost. If your fuel pump fuse didn't blow, your fuel pressure regulator stuck shut, the fuel hoses didn't rupture, your car didn't die from running so rich, and God hated you in general, there MIGHT be an overload on the pump causing it to burn up.
IT COULD CATCH FIRE. YOUR CAR COULD BLOW UP. YOU COULD DIE. SO DO THIS AT YOUR OWN RISK.
Liquid gasoline is very hard to ignite. Gasoline has to be atomized and also has to have a fresh supply of oxygen before it can be lit. A pump that is submerged in gasoline would have a really hard time A. getting hot enough to catch fire and B. lighting the liquid gas if it did. If your fuel level was low when this catastrophe struck, you could have big problems. I'm not skeered, but you should know what you're getting into before you do this next mod.
First, you'll notice in the pic above that the bypass hole isn't perfectly round. It is round with a slot cut for the fuel to get out. You need to take a small drill/dremel bit/etc and make the hole round for the first 1/4" or so above the metal part VERY CAREFULLY. The plastic is very thin here and you don't want to ruin your pump! Also be sure not to get plastic shavings into your pump. A piece of tape can cover up the pump outlet and you can put the bottom of the pump in a ziplock secured with a wire tie or rubber band around the pump body to keep shavings off of it. Blow the pump off before you uncover it.
Now that your hole is round, snag a 5/16" coarse tap and CAREFULLY tap you hole with about 4 threads. Also pick up a 5/16" coarse allen head set screw. The screw only needs to be about 1/8" long. After you've CAREFULLY opened the hole up and tapped it with a sharp tap, screw the setscrew in until it's flush with the top of the pump. It will look like this:
You can see where the plastic was stretched and discolored by screwing in the setscrew in this next pic. It was VERY CLOSE to splitting. I should have made the hole bigger, but it worked.
This mod works on both the low and high pressure pumps since you are completely disabling the bypass circuit on either of them. Usually the lower pressure pumps are cheaper, so save a couple bucks. This mod works on just about ANY in tank 255lph pump. I've used 2 pumps like this in Shelby Chargers and one lives in a 12second Thunderbird Supercoupe.
A bigger fuel pump power wire run directly from the alternator output will give you an additonal boost in fuel if you need it, but most don't. If you do that, be sure to use a relay that is triggered by the stock fuel pump wire and be sure to put an appropriate fuse in the hot wire to the pump.
Have fun whipping imports and BE F'NG CAREFUL!
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