I have been reading about the GDS spring, the OEM spring, the new Ford spring, Airdog 2, HPCM fuel pressure, BB mod, etc. and I'm confused.

I had a stock fuel system up until about a month ago. I installed the GDS fuel spring. Did not have a fuel pressure gauge when I did the install so I was going on what other people said.

Got my ITP fuel pressure line that replaces the motor fuel filter drain plug Monday and installed it last night. At idle I'm reading 102 psig.

Before I install my AD2 135/75 fuel pump that I got yesterday, I need to clear up a couple of things.

Before I install the AD2, do I need to go back to the OEM fuel pressure regulator spring?

Where are you guys getting these 55 psig to 70 psig reading from? Are you tapped into the back of the head's fuel rail?

Did you tap into the fuel system somewhere else other then the motor fuel filter drain plug?

Any advice would be appreciated.

DSMMH

 

I'm in the same boat, installed spring thinking everything was okay then the post start coming in about pressure too high. Has anyone contacted vendor to see what they say? I will try and get time today to do that but in the mean time I have pressure gauge ordered and will see what my pressures are when it get here.

 

When I first got my gauge my psi was all over. Once teh air bubles moved out it became more consistant.


Getting that spring might not have been a good idea.

Did you use the bb with the new spring??

 

I take my pressure from the ITP regulators return, it is set at 58.You really need to get yours down in a hurry or it will eat the injector O rings.

 

SmokerSteve......I let mine idle for about 20 minutes after I bled the air out of the fuel pressure line. Solid at 102. Increased engine RPM to 3,000 and it dropped to about 96 to 98. Of those who have the spring installed, I have no read that anyone has leaking injector O rings.......yet.

No BB installed with the GDS spring. Did not read or know about the BB mod until after I bought the GDS spring and installed it.

DSMMH

 

Yeah, I hear you. After reading about fuel pressure yesterday and then installing the fuel pressure line and gauge last night, I scared myself when I started the X. But I let it run, as it has been doing for the past month since I installed the GDS spring, and has not blown up yet.

The thing that does have me concerned, since I installed the spring, is I'm loosing fuel mileage which means I'm pumping more fuel somewhere but to where? Were the injectors sort of starving and with the increased fuel pressure they are now getting the correct fuel flow? If the injectors were starving, I would assume I would get miss fires and I have never had one of those since I owned the X.

To my knowledge, the only place I know on the 6.0 fuel system to get actual injector fuel rail pressure is to tap into the back of the head at the end of the injector fuel rail. I'm out of luck there because I have the fuel crossover line mod on my 6.0.

I want to understand what's going on before I install the AD2 since it has an adjustable fuel pressure regulator.

DSMMH

 

Here is how you get a check on your electric fuel pressure gauge.



This little mechanical gauge, installed with a tee on the end of the ITP hose, provide a check for the gauge I have in the cab for around $20.



100 psi is not good, unless you're looking for an excuse to pull your valve covers. What does your gauge say you have for fuel pressure with the stock spring? How about the stock spring and a bb?

 

Is the "ITP regulator return" the same place as the engine mounted "fuel filter drain plug"?

DSMMH

 

Did not have the fuel pressure line and gauge before I changed to the GDS spring so I don't what it was before the spring install or what it would have been with the BB mod. Will try to find the OEM spring tonight and do the BB mod and see what it is.

Is your fuel pressure line attached to motor fuel filter at the drain plug?

Dubya.......Thanks for the pics and info.


DSMMH

 

The ITP regulated return replaces the stock return with this part.The return is on the regulator and is adjustable from there.

 

Yes. My IPT adapter hose is screwed into the test port on the side of the stock fuel filter housing, just as shown in this picture.


I ran the hose under the air intake tube and up to the power steering reservoir that you see it zip tied to in the earlier picture. I tried to maintain a long downward run coming out of the fuel filter housing before coming up to the power steering reservoir to avoid any air entrapment in the ITP adapter hose.

Changing the spring isn't difficult. Just be careful not to lose the brass cup or the plastic air bleed fitting when you crack open the cover.

 

It is likely if you blow a oring that you pumping fuel into your oil. That would explain the loss of fuel. Something to consider/ look for.

 

Contacted Gillette Diesel and this is there response:
TOM. WE HAVE SOLD OVER 3000 SPRINGS WITH NO PROBLEMS. THE NAVASTAR ENGINEER THAT HELPED US DESIGN THE SPRING SAID THE FUEL SYSTMEM IS RATED TO 120 PSI. THANKS RICH.

 

buyer beware i guess....

 

have a truck in the shop now that lost an o-ring on an injector, engine ran away and melted 3 pistons. just a little fyi