loosing fuel psi blow thru a1000 pump

I am running a a1000 pump with a boost reference regulator and -10an feed and return lines. I am running a rbmc sending unit which I don't like but i set my fuel psi to 5 and drove it and was at 1 . set my fuel psi to 8 and went 4. whats going on? not a big enough vent. i do have the factory vent lines. should i drive it with the gas cap off? or get it to act up and take the fuel gas cap off. my a/f ratio is spiking way lean at idle at times. running at 12.2 under boost and goes to 10 when i get off it. was cruising around 11:5 a/f ratio.

 

Sounds to me it is either a venting of the fuel tank or a restriction in the return to the tank.

Could try running the fuel tank with fuel level at like less than 1/4 tank for a very short time to help with the venting to see if that might help.

For a very short time run a different return to a fuel can other than the fuel tank and see how much, if any is returned.

Try either or both.

 

I would look at the regulator first. What you are describing acts like you are getting a vacuum source not a pressure source. Hook up your vacuum gauge to the source for your regulator and see. Is your vac source in the air stream? Could be you are getting Venturi effect. Does not seem likely to me but who knows. Good luck with a strange problem.

 

Paul, did you get this figured out?

 

yea it was two issues..
The stock length pickup was picking up air when I got on it so I had to extend it about 6 inches to back of tank. I also found a ton of debree in my fuel filter before the pump. I just pulled them apart a week before but when I extended the pickup I must have sucked up a bunch of stuff.. Shaking my head:spank:
Vent line was kinked also!!
time for a ricks fuel tank!!

 

At least it was something simple. I put a sump on my tank and cleaned it out. I have to have at least a 1/4 tank to be sure of pressure but otherwise works fine. There are some really nice tanks out there now.