ok im running a holly blue with my oem lift pump. I get good pressure, never below 13 at WOT. and at idle it has my 15 psi guage pegged. however the fuel pressure needle is VERY erratic when i run at WOT. it will jump from 13 - 16+ very very rapidly, over and over again.


I thought it might be my lift pump going bad, so i unplugged it and i get 12 psi at idle and 0 at WOT with just the blue, so that's a no-go. i get the same results if i unplug the blue and just run the lift pump. so thats not it either

i remember when i first put the blue on with the fuel pressure guage. All was smooth, then it started acting up.

And yes, i have a valve in the line, and yes it is almost shut completly off.

Is anybody else's truck do this? is there a fix?

 

You might have toasted your guage pegging it like you are. I have a 0-30 and i have the same set up check my sig. I get 23 idle and 15wot. if you don't believe me look in my gallery.

 

well, dad has the in-tank pump and his guage does the same thing. (only at 6 psi at idle and 0 at WOT! ) it moves very rapid also. And it has never been pegged.

anybody else?

 

update - changed the fuel filter (10,000 or so miles) and now i cant pull it off of peg!