I just had the walbro 255 fuel pump installed-the high pressure one capable of 60+ psi. Well, I checked the fp under load, and it is still dropping when under load, causing me to go lean still. The fp pressure still doesn't go past 15psi, even though my regulator is rated at 22 psi max. Any ideas? this is very frustrating.... stock fuel line other than braided running from the rubber lines to the tbi.

 

Could be a restriction between the pump and the tb. If you could check the pressure at the filter you might be able to tell if it is a restriction problem.

Steve

 

Maybe you could use a vacum assisted regulator. From what I understand a vafpr will assist the sudden drop in fuel pressure by supplying vacum. Other than that maybe check with brian and see if it's chip related? Mine drops 1 or 2 psi under quick snaps of the throttle.

Oh, I also replaced my fuel pump relay when I did my walbro swap, just to be sure everything was in new and working order. It's only 3 bucks I think.