Tiderfish

I was just thinking my low fuel pressure, 20PSI KOER could be caused by a vacuum leak that I have yet to find and plug. Is this possible? Does the fuel system use vacuum on a 1995 EFI 351? It has a single tank.

Thanks!

joshtowal

The only vacuum line on the fuel system I can think of is at the fuel pressure regulator. So in short, yes it could.

Tiderfish

Thanks for the reply. I figured as much. What does the vacuum do to this regulator? Can I block it off?

joshtowal

Don't block it off. As the name implies, it wouldn't regulate the pressure and you would get extremely low fuel pressure if you got any at all. The regulator itself COULD be the cause of the low pressure. If that tests good, test the pressure at the hook up right before the filter, then drop the tank and test the pump.