Filter Head to injector #1 return line

[rockbender]

Has pretty much everyone eliminated the return line that goes between the filter head and the #1 (or #4) injector cap? I'm having some classic air intrusion symptoms and am highly suspect that the lift pump check valve is not functioning correctly.

The return line system is open to the tank without any check valves, so if the check valve in the lift pump was not working AND the return line was hooked from the filter head to the injector return lines then that line easily provides a 'vent' for the system to back siphon through the lift pump and to the current equilibrium level of the fuel tank. Is my thought process accurate here?

Is there any good reason to leave the line from the filter head to the return lines, or should that just be eliminated? If I remember correctly, it seems that Ford actually put out a notice to eliminate this line.

 

[icanfixall]

I don't recall Fors telling us to do that but. My truck came without that line setup. It sure makes it diffucult to bleed air from the filter if any gets in there. All the air must travel thru the injection pump and thats not a good thing. Oregon Fuel Injection sells both the small and large filter head check valve. I think the small one is around $18.00. Once I installed mine I had much better starts. Because of my turbo I needed to instal a Tee in betwen number one and number 3 injecter return line. It really does not matter where you run that line from the filter head. Just make sure its going to the return line system. Some have thought that the line from the filter was the return lines feeding back into the fuel system.. That is not how the return flows.

 

[rockbender]

That's a great point on giving air a place to go if it happens to get in the system. I also like the idea of putting a check valve on that return line from the filter head, even if it is at the risk of making things more complex than they need to be. I suppose it wouldn't hurt to hook up a piece of clear tubing at that location to see which way things are draining.

I was reading earlier that there is supposed to be a factory check valve on the return line system? On the backside by #8? I'll double check, but guessing that I do not have that piece in place.

I guess having the return line off the filter head is also a key element to either going with the full time e-pump or momentary e-pump priming system so the air can actually have a place to purge.

Thanks for clarification on my reasoning!

 

[idiabuse]

I put a dedicated bypass type regulator to return fuel back to the tank. both injector returns are plumbed into the return line, air intrusion is a distant memory...



Javier

 

[icanfixall]

This brass check valve in the filter head is only able to pass air. It has a small spring internally to it and will close a bearing ball when fuel pushes it. So air flows out but not the fuel.. Nice idea right there. The psd fuel filter heads have the same idea but just a little differant design and spring pressure. They run about 40 lbs compared to our 7 lbs of lift pump pressure. Then our DB2 injection pump can make 5000 lbs of pressure where the psd makes at least 20,000 lbs or the injecters wont fire. Can make as high as 35,000 lbs stock. When the pumps are modified they run sky high pressures.

 

[dirtbiker]

idiabuse, you mentioned a regulator on the return line. That was my question about a 6.9 swap I was doing, in which I had the return just dumping into the tank. What did you use, and how did you set it up? Thanks.

 

[icanfixall]

In the tanks of the oem trucks the return line has a valve if you want to call it that. All it is a rubber lips that will pass fluid one way. Same thing is found under the cowl drains but much larger in size. Same principle

 

[idiabuse]

All the OEM fuel handling hardware is just garbage if it cant last.
I looked at about 3 OEM air valves and the the ones I saw had no valve/ball in them.
They seem to be just a bleed hole fitting that returns fuel into injection return system.

I rebuilt my whole fuel system on my truck because the OEM stuff is really silly stuff.
So I have the two OEM tanks and both have a 5/8 hole on the bottom to deliver fuel
to my electric pump by gravity.
At the engine I replaced the OEM filter head with a AC Delco secondary style diesel
fuel filter assembly, Cheaper easier to get filter/water sep Either a 33120 or a 33815
At the filter head there is one feed and two exits. One exit goes to the injection pump.
The other exit is to the Mallory Regulator 4309 and then it returns to the tank.

All the OEM slave labor items are removed from my truck to extend my driving pleasure.


Javier

 

[icanfixall]

Idiabuse... Were you looking at new air bleed valves or used valves. I too thought these were a straight thru flow of a very small amount all the time... Till I actually bought a new one. I can't blow back thru it but I can draw air thru it from the filter side.