FASS return spring/pressure, help?

[JCyrbok]

I have had a FASS system on my truck for about 2 months now. I run about 12. 5 psi at idle and about 12. 0 running down the highway at 70. I can pull it down to about 10. 5psi at WOT. Pressure can sometimes be alittle erratic too. The only mods are a DDTPM and a Scotty II. I am running a NAPA 2micron filter on the pump, which I feel accounts for some of the lower pressure.



I have read some threads that mention the return spring/check ball being weak or needing to be stretched. I e-mailed Piers where I got the FASS from as DPP said the dealer would take care of me, but have not heard back from them after several weeks.



Where is the spring/check ball located? What would be the proceedure to remove it and the check ball, so I can check/stretch the spring alittle to see if that helps.



Thanks in advance,

J-

 

[MikeS1]

If you look at the front of the pump facing the engine you will see 2 fittings, the one on the bottom is labled with a "P" pull that fitting off and the spring is right there, very easy to get to, with my mods I can pull it down to about 12 wot and at idle about 14. 5 to 15, DPP has 2 springs standard a 10 to 12 and a 14 to 15 sounds like you have the 10 to 12. Mike

 

[JCyrbok]

Thanks Mike, sounds like about a 3 minute job.



J-

 

[tractorface]

Its behind the line that feeds the VP44 Your fuel line is attached to a fitting on the Fass. Take the line off then remove the fitting it is right behind it. You won't lose much fuel and it is only a 3minute job like you said. If you want higher numbers get the next spring up. I plan to try and find a spring between the two offered by DPP cause I want to run 15 psi.

 

[nickleinonen]

can you guys just not shim the spring??? that would increase the tension on it and effictly increase your pressures,,

 

[JCyrbok]

OK you guys just confused me. My bottom fitting is marked as "R" and is the return line to the tank.



The upper front fitting goes to the VP and is marked "E". Is the spring located behind the fitting to the VP (upper front) or the Return Fitting (lower front)? I dont remember any springs/check balls in the upper port to the VP. WHich is it??



From the install manual and confirmed by me the ports are labeled and function as such: "T" inlet from tank on back of pump.

"R" Return line to tank lower front of pump.

"E" Outlet to the injection pump, upper front of tank.



"H" and "G" heater and gauge ports.



Also if it matters I have the full FASS system with the filters, not just the pump.



Thanks

J-

 

[pgleavitt]

Looking at the pump,the hose you need is on the front of the body or block that the filters are screwed into. This hose is the return hose that goes back to the filler neck. Remove this hose and remove the fitting that screws into the block. The spring and check ball are located behind this fitting and will likely fall out. I have streched the spring before and had to go back to give it a little more.

 

[JCyrbok]

Thanks PLeavitt, thats what I was thinking.



Thanks

J-

 

[MikeS1]

Thats wierd, where the spring is in my FASS is labled with a "P" sorry to steer you wrong J. Mike

 

[tractorface]

Pleavitt is correct. Guess I should apologize as well. I had a mental lapse when I told you it was the supply to the VP.