Boost sensitive regulator

[Turbobug65]

I have had problems getting fuel to my turbo motor from day one. Over years and trying a bunch of things found out that the internal bypass in my Holly blue pump was set 7psi. I could set fuel psi at idel, drive it around off boost and everything was fine, the minute I got on boost my pressure would drop to zero. I found out that Morroso makes a replacement spring further Holly pumps that makes the bypass go to 19 psi. Everything seams to work now. Has anyone had this problem before?

[ProTurboVW]

A easy fix would have been to have your regulator setup for boost sentive. Only need this for side drafts, which I asume you are running. Side draft don't hold much fuel and will get sucked dry once on boost. So you setup the regulator. So when the motor goes on boost the regulator goes from like 3or 4 psi to 7psi on boost. That's why you where having trouble. Asuming your regulator was not done.

[Turbobug65]

Yeah the reg was set up, a jolly tapped with one way check valve. When having this problem no body I talked to in my circle of PRA buddies no one knew of that spring in the pump caused the problem.  I run a Automotive reg now that is built for referencing boost, the one bad thing is, 3lbs is the lowest I can go on psi so I thought about giving the holley reg another chance. I know I can getthat one down to 1.5 psi.

[Ohio Tom (DdK)]

I think I know what the problem is.
I have had the same thing happen to me. That's why I run an "in car" fuel press guage.
Every so often I "Load test" my fuel delivery.
I hook up a flow control valve to my fuel regulator. The other side of the flow control valve has a hose that runs into a container with gallon markings.
I monitor fuel pressure with a "known good" guage. I then fire up the fuel pump and open the flow control valve slowly to the point where Im flowing enough for 400hp (I think its 135gal/hr, or 2gal/min roughly). I then take a fuel pressure reading.
If it's down more than 1/2-1 psi, It's time for new fuel pump.
I did this test last season and faild. I installed a new pump and it fixed the problem (Carter).
I took the old pump apart and only found minor scoring here and there.
It didn't LOOK bad, but it sure was.

I work on Hydraulic sysems often at my day job. I used to tear down old vane type pumps. they are weird like that too. They will make tons of noise and drop output. Open them up, It's hard to find what's wrong with them too.

[Turbobug65]

Yeah I to often thaught that the pump was no good ski rebuilt it and still hate same problem. Outline I mentioned earlier, after I changed that bypass spring I think that solved my problem.  I know that the Automotive reg works at one to one ratio. So above that 7 psi the bypass was working and shouting down my flow. I really wanted to put a fuel pressure gauge in the car also, then I can see what's really going on. Or mountains go pro camera and make a pass and see what happens.