Just finished doing return line kit. I used a Napa one that the previous owner had already purchased. Shoulda used the viton 111 o rings but didn't see that until later when mine were still leaking. I also installed the facet 40222 pump replacing a cheap Mr gasket type pump. My fuel pressure at the outlet of the fuel filter went from 4 psi at idle and less than 1 psi when revved, to constant 6 psi at idle or when revving. My issue is that the new return lines are leaking, three of them this time instead of just one. I did a search and someone said older IP can have alot of bypass that can pressurize the return circuit and cause leaks. So I put a hose on the IP return outlet and ran it into a bottle. I plugged the other return hose. This apparently stopped all the leaks. It took about 10 mins to fill the gallon bottle. Is this a sign the IP needs to be refurb'd? Or is this due to the new fuel pump? I could try a regulator on the outlet to drop it to 2 psi or so. Just looking for ideas on path forward. I am planning on buying the viton o rings to see if that helps, but I don't think that's the real issue.

 

Excess inlet Fuel is dumped from the check valve on the filter head back to the Return lines.

The IP has it's own Transfer Pump and Pressure regulator.. excess fuel is passed the vent wire and the housing pressure is maintained by the Housing Pressure regulator (that is the fitting you have your hose in the jug connected to) the DB2 makes a good amount of fuel return even with the Inlet pressure at 2 PSI.

I call what you see Normal Operation.

EDIT: By running Higher than OEM inlet pressures you are increasing the Return Pressure.

 

Thanks lonewolf. Would you say a pressure regulator to reduce fuel pressure at the inlet is the best solution? Or do you think the viton o-rings will allow the returns to seal? I know other people on here have used this fuel pump without these issues.

 

others have used the Dura lift pumps with no issues .... just make sure your Return lines going to the tank are not restricted You could Put a 15 PSI gauge on the Return and see what Pressure it is making just to know where you stand .... sometimes seating those Return cups can be a Bitch..... the last 'O' Rings I used were the Green ones From a Harbor Fright Kit .... they been in there for over 5 years with no leaks... I used STP to Lube em when I assembled them BUT I am Running the Mechanical Lift pump Old style Carter rebuidable type.

the 'O' Rings from McMaster Carr work well too I think they are the Viton 111 ... someone recently mentioned a Square Cut 'O' Ring from McMaster but I've never tried them.

Now a Pressure Regulator is Probably not a Bad Idea IF it can still supply the Volume... Pressure to the IP is not as Important as Volume. Since the IP makes it's own Pressure demands internally all it needs is Positive Pressure on the inlet (1 or 2 PSI)


EDIT: here is where they were mentioned .. post # 30- #31 https://www.ford-trucks.com/forums/1...n-rails-2.html

 

x2

Reseat the return line caps and you'll probably be good. I had to reaseat a few last time I did return lines.

 

the 40222 is supposed to put out some serious volume, so i think even over a regulator restriction it would be ok. I am planning on checking the return line back to tank for restrictions, just thought of that when discussing the issue with a buddy this morning.

When seating the caps, i am pretty sure you can feel a distinct pop when the go into or out of the correct position. when they are in the installed position they are nearly bottomed out against the injector body with about 1/16-1/8" between the top of the cap and the bottom of the injector line fitting. I verified this with some shims. The shims seemed to help on a couple of the leaky caps, but the #8 cylinder leaked no matter what i did until i removed the IP return. I also saw the square o-rings at mcmaster, but ended up buying the x-rings instead. They are supposed to be much better at sealing pressure than the standard o-rings. we'll see. https://www.mcmaster.com/6540k135

 

with STP as an install lube there is no feel to the caps going on they just go on all the way down and set on the top Flat of the injector, there is no grooves cut inside the caps for the 'O 'Rings the new style uses larger lines... More return

 

The plot thickens.... So I did an experiment tonight. The local advance had a Mr gasket 1-6 psi fuel pressure regulator, even came with three sizes of fittings. I first ran the IP return line into a jug for 11 minutes which almost filled the jug. The fuel pressure at idle was 6 psi steady with no regulator. The fuel pressure is measured electrically after the fuel water separator filter. I then added the regulator between the pump and the filter. I set the regulator to run at just a hair below 1 psi per the same electric gauge and ran it for another 11 mins. The qty of fuel was slightly less than at the higher fuel pressure, but not significant in my opinion. Nothing was leaking at this time. Then I hooked the IP return line back up to the return system and ran the truck at 1 psi looking for leaks, no leaks. Then I opened up the regulator all the way, which was only around 4.5 psi on the gauge. Checked for leaks again, and nada. So either the o-rings sorta "set" overnight and are sealing better, or the key difference is between 4.5 and 6 psi... But since the volume of fluid returned from the IP is almost the same, I don't think that could be it.
I have the better o-rings (x rings) coming from McMaster so I think I will put those in next week and see if it will work without the regulator then. I do not want to run the regulator long term bc the cheap ones are known to be leaky (and the expensive ones are $$$). In the mean time, looks like we are sealed up! Thanks for everyone's input and I'll let y'all know how it goes.
edit: mr gasket 9710 reg was 31 bucks.

 

of course there isn't much difference ... one reason the IP passes a lot of return is by design to keep the IP Cool

BUT remember the Housing Pressure regulator must maintain Housing Pressure

Basically the IP is saying Dilligaf... IF you own a Shovelhead you understand .. I'm a Pan guy myself

Your Excess Inlet fuel is dumped into the return at the filter head anyway. Unless you Blocked that Return Check Valve/Orifice

 

That's a great diagram, shows it very clearly. My return going to the filter head is still there. Just weird that it sorta sealed itself overnight. I do own a shovelhead, started life as a 75 superglide and now is a hardtail chopper. I want to put the shovel back into the superglide frame and get a pan for the chopper, just ran outta money during the build. I built it in 2013 for the horse magazine amateur chop off.

 

clean Built I like it