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Discussion Starter #1
Took the fuel pump assembly apart to figure out why I get poor fuel delivery at close to a 1/4 tank of fuel. I also wanted to see how the pump was modified for the return. They put the output out the top in the middle and submerged the in tank pressure sensor. I can't get the Kpro to fire on my computer, but is that something that is normally shutoff so submerging makes no difference? This is an E85 setup, and has a short, but really fat on one end unmarked fuel pump. The strainer also had a hole and the guage sensor had corroded at the terminal, so I fixed that as well.
 

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Vaginal Lubrication Tech
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1st let me say i have never fuct with an e-85 setup on an rsx.

that being said, on a normal turbo set up with a return line, poor delivery at/or below half a tank is usually because the return line dumps directly into the tank instead of being routed back into the plastic housing for the fuel pump.
 

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Discussion Starter #3
1st let me say i have never fuct with an e-85 setup on an rsx.

that being said, on a normal turbo set up with a return line, poor delivery at/or below half a tank is usually because the return line dumps directly into the tank instead of being routed back into the plastic housing for the fuel pump.

Hey thanks, the return does just hang down. I'll extend the line to the housing. The builder made two holes in the housing, I'd guess to pick up more fuel and perhaps that's where the thought breaks down as it would also empty it as well.

Would you use the small inlet at the rear and let it fill it without any holes--this would make more sense as a return into the housing would also just go out the holes--given the level of course.

Initialy I did this as the fuel level sensor also crapped out. With a meter I detected the crimped yellow line had corroded and all it took was to clean and solder it. Other than that, the other parts are holding up fine to E85.
 

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Past Driver’s Ed
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1st let me say i have never fuct with an e-85 setup on an rsx.

that being said, on a normal turbo set up with a return line, poor delivery at/or below half a tank is usually because the return line dumps directly into the tank instead of being routed back into the plastic housing for the fuel pump.
^^^ This! Drilling holes in the pump housing will make things worse. I been running on E85 for 4+ years without issues.
 

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Past Driver’s Ed
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Let me jog a memory cell - I omitted (remove completely from housing) the stock fuel regulator and the semi flex hose that feeds fuel to it with a new peace of flexible hose that can be submerged in fuel. Connect the new hose from the underside of the cap directly to the inlet of the orifice that feeds fuel back the fuel pump cage. To be on the safe side to avoid restricting the return fuel flow, I carefully drilled the plastic orifice the next size bigger. I wish I took photos fuel pump assembly, but here are some photos of the rest of my setup.






 

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Discussion Starter #7 (Edited)
^^^ This! Drilling holes in the pump housing will make things worse. I been running on E85 for 4+ years without issues.
What I don't get is the pump housing and how the needed fuel gets in there. The damn thing looks like a submarine and I see the return hook up and can enlarge. How does it pick up fuel when it gets low as there is no holes to let fuel in? Thanks for the pics.
 

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Past Driver’s Ed
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Can’t find a photo on the web, but trace the route of the fuel line on the discharge side of the OEM fuel pressure regulator. Where the line connects to the fuel pump cage you will find an opening that with the help of the pressurized fuel coming from the pressure regulator travels through the orifice that acts as a vortex which draws additional fuel from the tank. The fuel pump cage acts as a mini reservoir to keep the fuel pump from running dry under any g forces.
 

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Vaginal Lubrication Tech
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Here is how i ended up doing mine.





i gutted the OEM regulator. When i cut the top off it, i ended it with jagged, uneven edges. i got lucky and that allowed a fitting to just thread in and make a solid connection.
this is what i took off the FPR





 

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Discussion Starter #10
Thanks so much. I ran the tank down and the pump starved a few times. I filled and made a mile and it quit pumping--guessing it got too hot the other day and now crapped out. Will do your mod when apart--check fuse and cross fingers first:)
 

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Discussion Starter #12
Burned out the pump and it blew the fuse--chalk up another dumb mistake. It has a Walbro 450 and was easy enough to replace.
 

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This is the best way to setup your pump. I go out of the pump and into the AN fitting at the top for feed out of the cage, return comes from stock return location at the top to the stock return in the cage. I do not use the regulator or anything. I just put the return hose into the cage. Any other holes at the top of the cage get plugged. Do not drill holes in the cage bottom AT ALL. How my system works: the return sprays right into the fuel pump filter pick-up. Retains all plastic housing pieces. Zoom in on this photo for more details.

 

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Discussion Starter #15
Btw, this setup is proven past 650whp.
Up and running again and I'll have to redo a pump as the builder made what you did impossible. I have the hose, but he also took the floor out of the top of the pump so fuel just rains down instead of flowing through the inside return hose.

So how low do you dare go before you fill? I stay as full as possible, but after I do what you did, I'll have a better safety net.
 

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I have noticed fuel starvation characteristics in the past around the 1/4 tank zone but it never happened again and I have pushed it to E. I think it was a faulty fuel pump. However, you just need to realize that if you are at 1/4 tank, just don't do a pull. It will slosh the fuel to the rear and almost sure to starve. I don't do pulls if I'm under 1/4 but I will drive till it runs out of I have to. Not a huge deal.
 

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Discussion Starter #17
I have noticed fuel starvation characteristics in the past around the 1/4 tank zone but it never happened again and I have pushed it to E. I think it was a faulty fuel pump. However, you just need to realize that if you are at 1/4 tank, just don't do a pull. It will slosh the fuel to the rear and almost sure to starve. I don't do pulls if I'm under 1/4 but I will drive till it runs out of I have to. Not a huge deal.

Good to know, thanks
 
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