How long should the fuel system hold pressure when you turn the ignition on to build up pressure and then back off? I am building about 42psi when I turn the pump on and when I turn the ignition off, it drops to 0ps1 within a matter of seconds. I've got dual walbros for pumps, only one runs until I see 6psi in the manifold, and 80lb siemens deka fuel injectors and a holley fuel pressure regulator/fuel rails.

 

What does it register with no vacuum line attached to the regulator?

 

With the engine running at idle I see about 42psi, when I take the vacuum line off, I still see about 42psi. This is about a 900 rpm idle. I haven't tuned it yet. I'm waiting to work out all the bugs. My cam specs are 224/224 .577/.582 114 LSA.

 

May wanna check the vac line to see if it has fuel on it, you may have a fpr leaking the fuel into the manifold when you shut it off which would cause the rapid bleed off. The idle pressure should be a little lower with vacuum than it would without.

Does it have a hard start?

 

I think it starts pretty good for not being tuned.

 

If the pressure doesn't rise when you remove the vacuum source then you likely have a bad diaphram in the regulator. Did you have any fuel in the vacuum line when you removed it?

How did you setup your dual pumps in the tank?

 

Its Lonnies dual fueler setup. I haven't started it since I (hopefully) fixed the fuel injector issue. I'll check to see if there's fuel in the vacuum line.

 

If your top injector o-rings were loose, as described in your other thread, the system isn't going to hold pressure. Have you rechecked the pressure loss after (apparently) solving the o-ring problem?

 

I'm waiting on a shifter cable in the mail, then I'll start it up again. The o rings weren't exactly loose, the injectors were just not seated into the injector boss enough. I didn't see any fuel leaking anywhere when I was experiencing the fuel pressure loss before. I'd assume that if air was leaking into the system, then 43psi of fuel would show up and leak out somewhere. I'll test again in a day or two.