Fass Fuel System

Assuming it's pulling some air through it?

 

No but it will cause the check valves in primer hand pump to not open fully with positive pressure. You need to buy the little (block) that replaces the pump. You don't need primer pump anymore with the fass.

 

So with the fass pump. And a block to replace the hand pump, do you just prime it by turning the key and cracking the fuel filter to bleed the air?

Also, I sent the truck into the shop for some water pump work and had them test the fuel pressure. Old pump is pushing 75# at idle and 105 revved up. So there's no restrictions, I'm just getting used to truck. Getting great mpg too.

 

And you won't show restriction sitting there with no load on engine. Run it down the road and load down the engine with the brake pedal and watch the fuel pressure gauge...you will be surprised !! Did you take off the other filter like what was suggested ? If not your waisting your time playing with it.

 

I haven't removed it no. Only real reason for it is if it's truly not causing restriction, then why not have four filters cleaning. One day I need to move my vacuum gauge and also add a pressure gauge on the high side.
I'll try bypassing it and see what it does. It's just hard to believe that would restrict if the fass pump is keeping a constant pressure on the engine pump on the low side. Do you know what pressure that electric pushes to the engine pump before cycling it back to the tanks? If not, I'll have to call and see.

 

Think of it this way. Every filter you have in the line is like taking vise grips a screwing them down a little more closing the hose up. Making the pumps (fass and engine) work harder to push and pull through the smaller hole.

 

Makes sense. I got nothing to lose to bypass it! I just blew a tire so I'm headed back to the yard anyways. Ill experiment when I get there. Ill let you know what happens.

 

Btw. My vacuum gauge doesn't move when I have a load on and working the engine. Wouldn't it move a little if that original filter is restricting? Assuming 18psi that the fass pump provides more than enough pressure to push through a filter. Just thinking out loud.

 

No, like I said it reads vacum not poss. Pressure.

 

Thoughts on FASS or Airdog on a new cummins X-15? or should wait a certain milage b4 install??