afpr connected to fps question

[stevetalon]

So I've been having problems with being lean at wot on e85. Today I got on it in first and got a loud pop. I'm thinking this was a lean missfire and I noticed that my vacuum line going to my afpr was still connected to the fuel pressure solenoid. I bypassed the fps and just hooked up the vacuum line to the manifold and it seems to run at my target af of 11.8-12.0. Could this cause you to run lean?

 

[viprez586]

As manifold pressure increases it "pushes" on the diaphragm to reduce the amount of fuel allowed into the return line.
Perhaps there is a leak in the solenoid, or it's stuck. Either way it's unnecessary, leaving it disconnected the only side effect is potential extended hot-soak start.
Either way I'd keep it how you have it, running lean under boost means you'll be kissing your engine goodbye in a hurry, but you should be okay just doing it that once.

 

[jeffo]

The vacuum/boost signal to the FPR is what causes the fuel pressure to change 1:1 with boost. I've seen quite a few cars where the solenoid was restricting the boost signal, so the fuel pressure wasn't rising 1:1, so the car was leaning out under boost.
As viprez said, as long as you can put up with the car stumbling a little bit after a hot start, just leave it bypassed.

 

[stevetalon]

Ok thanks I'll keep it bypassed. Right now I have my injector comp set at 560cc for my 880cc at about 43.5 base pressure for e85. At wot i'm seeing 11.8-12.0 but I was watching my wideband the other day and when I got to a higher rpm( like 5000+ I started to lean out to like 13-14. I shouldn't be running out of fuel with my t28 at 19 psi right? The only think I can think of is a clogged fuel filter or could I possibly be overrunning the 1g maf?