Raptor700yfz

I have dual pumps in my 1954 International Harvester R-120 with a turbo 5.3l ls motor I just added the pump without really thingking about it so I can turn my boost up 13 psi on E85 but I believe that my big pump (450) is holding the little pump shut by pumping fuel back through the y-block into the tank because when I get in it, it first goes to 9.8 aft and then jumps to 13.8 so I just wanted to see if anyone could think of a good solution maybe a one way check before the y-block or will it hold that shut too or do I just need another bigger pump? Now I have discovered that aeromotive says you should not use pumps with more that 20% different flow rate so just seeing if I can make it work. Anyways anything helps thanks. And just a FYI the pumps are two 8 an line and a 10 an exit and 6 or 8 an return I forget.

Raptor700yfz

I have it idling at about 65-68 psi and when I get in to boost and it first reads lean my fuel pressure makes it to almost 80 psi I should have enough pressure I would think and it never drops pressure.

Raptor700yfz

I just ended up reflashing my Ed abut ended up not being a fuel pump problem but a ecm fueling issue.