We just went through a few evenings of chasing a fuel problem on my kid's rpu. First in line after tank is a fuel filter, then a Carter electric pump, then a Mallory fuel pressure regulator with hose going to a fuel log on the firewall. If we let the car sit for a day the fuel pressure gauge would read zero and when you pulled the line off of the carbs it was bone dry.

The electric pump was working fine and when we pulled the line off the end of the regulator it was dry, so we felt it was sticking. Tore it apart, nothing wrong. Finally, we removed one AN fitting going into the fuel log and there was some kind of gooey stuff in it, sort of like clear silicone. We cleaned that out and the problem went away. We have no idea how clear silicone got into the system since he used none anywhere, but we suspect the one fitting he pirated off of the Camaro drag car engine I have might have had some inside where we missed it when we cleaned it up to use.

The silicone was evidently acting as a flap and would sometimes let fuel pass and then close up and not let it pass. Very strange.

Don