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Lets talk about our stock fuel pump modules and modifying them.

5K views 24 replies 6 participants last post by  ZXthrizzle05 
#1 ·
Recently had my fuel pump module out and had one of the gaskets that seal the fuel pump outlet.



There are no replacements for this, only option is to buy a whole new module or steal one out of another module. When i removed the damaged one i was surprised at how small the outlet is going to the fuel rail.





From the outside it looks like a 5/16" hose but the hole is only 1/8". Granted the system was never designed to handle the power that some of us are requiring from it with turbos or superchargers.

There is also a check valve inline from the fuel pump to the outlet of the fuel pump module that is also 1/8".





This is just to keep fuel in the system pressurized so that you can just crank and go. By eliminating it all i should have to do is cycle the key two 2-3 times to prime the system. Not much different than having to let a return style system run for a couple of seconds before starting.

The outlet that returns fuel to the canister and venturi setup is the same 1/8" diameter.

I am currently running the gt40 fuel pump which does flow more than the stock pump. I have data logged both back to back and the stock pump on my current setup will max out about 2/3 the way through a 3rd gear pull from about 2-3000rpm to red line. The gt40 pump just maxes out just before red line.

What i am going to try next is running 5/16" hose straight from the pump to a 5/16" tee then run 5/16" hose to both the fuel pump module outlet that feeds the fuel rail and to the connection that feeds the canister/venturi setup. This should increase flow to the rail but drop pressure slightly. The computer will then increase voltage to the pump to maintain the desired pressure at rail in theory.

Yes i know switching to return fuel will eliminate all of this but i am willing to try this to see if it could work for some people that don't wanna go through the trouble of switching to return fuel. Also i want to eliminate the seal that failed and try to get a little more out of the gt40 pump before i do switch to return style fuel system.
 
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#5 ·
I guess i should of mentioned that this is in one of the recall pump housings since i have a 2000 that had the recall done.

Can you give some specifics on your year, model, engine to add some info about the pump module. Like 2004 2.3l ZX3 or whatever it is.

I know Randy from FSWerks said us older Focus guys could run the 03-04 duratec pump module but that there are different settings in the tune.
 
#7 ·
Started mocking it up.

First a 5/16" tee that i cut one barb off each side so it wasn't so big.





Then fitting the hose in and figuring out the best routing so as not kink the hose.









I have another piece of hose coming and more clamps tomorrow. Hopefully get to try this out soon.
 
#14 ·
This has to increase the flow, but won't know till i datalog it to see if it's still pegging the full pump duty cycle or not.

This is what i have done so far.







 
#16 ·
The routing is exactly the same as the factory setup just with 5/16" flow instead of the bottlenecks that are there with the stock plastic piece on top of the pump.
 
#17 ·
Unless you have the regulator / restrictor in the hose off the T as a return you wont have much fuel psi to the fuel rail

The round plastic piece that you took out of the system is the "regulator" for the fuel it has a ball and spring inside as well as reduces size going through , to do a return fuel system you have to gave something to shut off the fuel as the demand goes up

Tom
 
#18 ·
Please give a little more explanation.

This piece is inline on the outlet to the rail.





So removing this will cause less pressure to the rail???
 
#19 ·
How did you put that plastic piece on the outlet of the rail ? That is the regulator for the Focus return fuel system , If you placed this on the fuel rail on the engine why not just do a rise and rate fuel psi regulator and just a single line out of the fuel canister from the fuel pump to the fuel rail .
I am guessing if this is the cas you have a return line going back to the gas tank ?

If you have a hose from the fuel pump to a T off the T one line back into the canister one line to the fuel rail the fuel line going from the T to the canister is going to dump all the psi from the fuel pump

Maybe the pictures are not showing everything your doing ??? give me a call 704 249 3745

Tom
 
#20 ·
How did you put that plastic piece on the outlet of the rail ? That is the regulator for the fuel system
If you have a hose from the fuel pump to a T off the T one line back into the canister one line to the fuel rail the fuel line going from the T to the canister is going to dump all the psi from the fuel pump

Maybe the pictures are not showing everything your doing ??? give me a call 704 249 3745

Tom
Didn't put in on the outlet of the rail! lol

It is inline on the hose that goes from the pump to the top hat that feeds the fuel rail. If it's regulating the the flow it's doing it on the outlet of the fuel pump module feeding the fuel rail. This would cause more pressure on the return side back into the canister wouldn't it?
 
#21 ·
This is the "tee" that comes right off the fuel pump outlet. One side feeds right back into the canister and through the venturi to keep the canister filled. The barbed side feeds the fuel rail.









Before it exits the Fuel pump module it feeds through this.









Cracked it open to see what all was in it.







Looks to be just a check valve to keep pressure in the fuel line up the the injectors.

So Tom by removing this like i have done you are saying i will less fuel pressure at the rail?
 
#24 ·
you could try switching to a corvette fuel filter. it has a regulator built in for returnless and has a lot larger diameter lines

they are used on the nb miata to delete the stock intank fuel pressure reg when swapping to a ls1 bc the nb miata and vette are also returnless.

how ever neither system uses a voltage controller on the pump like the focus. so a regular 255 pump can me used

you can see in the pic the two lines on the back side are from pump to filter and return line. the third line to rail is still capped in the pic

http://www.swaptastic.net/ls1_miata/images/vette filter 2 (Custom).JPG
 
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