No No No ... the control box goes BETWEEN the FPR & vacuum tree ... there is no "second vacuum source".
1) disconnect the red vacuum line from the FPR
2) run a line to the ZEX box
3) run a second line from the ZEX box to the red vacuum line that you disconnected in step 1
Thus, the control box now sits between the vacuum line and the FPR, allowing it to bleed vacuum and thus control fuel pressure
Pictures are little small, but you should see what I'm talking about:
