How much pressure, if any, in return lines?

[losfinch]

I know this could be a dumb question but here goes...

How much actual pressure is there after the OEM fuel regulator in the return line? Any, minimum?

Don't ask why.

[99bigred]

very little...under 5psi i would think.

[alabamafrog]

Unless there is a problem in the tank where the return goes into the mixing chamber then there would be very little like said above. If there was a blockage then I'd guess it could be near 100 psi or more.

If your worried about the seal where the line hooks to the regulator then its okay, mine is all boogered up and it don’t leak but then again I did the intank mods and deleted the mixing chamber.

[07OUTLAW]

[QUOTE=alabamafrog;497190]Unless there is a problem in the tank where the return goes into the mixing chamber then there would be very little like said above.[QUOTE]

It should be under very little pressure........

But I've got to ask ...... WHY??

You got me curious by saying not to ask why,

[losfinch]

Originally Posted by 07OUTLAW

It should be under very little pressure........

But I've got to ask ...... WHY??

You got me curious by saying not to ask why,

Ok...here goes to satisfy your curiosity:

I'm brain-tinkering a DIY air-bleed system to help get the air out of the deadhead zones. And being the cheapskate that I am, I figured that if I could place the air bleed valves directly into the outlet fuel ports on the head then from that point on the plumbing and connections to tie into the fuel return line could be as simple (and cheap) as barbed fittings, clamps and diesel grade fuel hose. If there is no real pressure to worry about then why waste the expense on high pressure hoses and fittings.

Now...I'm sure I'll get some flak for this but if it works it'll be an investment of about what, maybe $20-25 to get the majority of the air out of the heads, quiet up the motor, help out number eight injector, etc. If it doesn't work I can upgrade the lines and fittings then.

Here's a quick layout I drew up to help visualize a bit: diy air bleed system layout pictures from trucks photos on webshots

[99bigred]

how are you going to regulate the pressure in the head?

[strokin_early_99]

^^^^^what he said.


Why not first do the intank and pre pump mods(Hutch mod). That makes quite a difference right there by getting rid of some of the air leaking into the system. It also gets rid of that stupid mixing chamber in the tank.

[losfinch]

Originally Posted by 99bigred

how are you going to regulate the pressure in the head?

The OEM pressure regulator will be functioning as normal and then the air bleed valves on the outlet fuel ports of the heads will be dripping so little fuel that the pressure should be easily maintained.

I am basing that upon the experience of others who have made their own systems (.015 orifices or set screws set to drip very slowly) and the basic way that some "kits" do it that way. My main difference is that I want to place the air bleed valves directly into the fuel outlet ports...the others put one air bleed valve somewhere after teeing the two head return lines together which requires high pressure lines to do that.


As far as the pre-pump in tank mods, those would be done as well.

[strokin_early_99]

Sounds like it is time to put your picture to work. Build it up and report back. I would also make sure to put an in cab gauge on the system so you can monitor the pressure at WOT.

[dieselroller]

i have a 96 7.3l psd. i had to replace a plug on what i think is an oil pump on the front center top infront of the fuel filter cup. cause it plew oil all over the top of the motor. i had to remove two lines on what i think is a fuel pump or regulator on the driver side of the fuel filter. everything is fixed now, but the truck doesn't start well i have to pump the gas and then it starts. there is an air valve in this fuel thing. is it supose to be pressurized? and how much? once it starts it runs fine. can someone help?