The older FiTech units don't have the line from the pressure regulator to the manifold vacuum port. So I asked a FiTech rep about and wanted to share the answer here. I have read many different opinions online on what is this for but it is good to hear from the manufacturer that this is just for safety.
The vacuum line actually is the safety thing not a mechanically functional thing. We're going to a manifold vacuum port on the bottom of the throttle body. The reason to change is if that line is left open and you ever had a regulator fail or puncture it would pump fuel out of that nipple. so by running a line to the bottom side of the throttle body if that ever happened it would just put the fuel into the engine and not spray fuel all over the engine compartment.
The older FiTech units don't have the line from the pressure regulator to the manifold vacuum port. So I asked a FiTech rep about and wanted to share the answer here. I have read many different opinions online on what is this for but it is good to hear from the manufacturer that this is just for safety.
The vacuum line actually is the safety thing not a mechanically functional thing. We're going to a manifold vacuum port on the bottom of the throttle body. The reason to change is if that line is left open and you ever had a regulator fail or puncture it would pump fuel out of that nipple. so by running a line to the bottom side of the throttle body if that ever happened it would just put the fuel into the engine and not spray fuel all over the engine compartment.
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1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump
