I've installed a set of used PSE mufflers, complete with the vacuum lines and switch wiring to an ashtray switch. I have checked that I get 12v properly switched at the solenoid electrical connection (disconnected in the photo) but my PSE is always on. (Yes, I know that is how I should leave it all the time ) I have checked and rechecked all my vacuum connections and from what I can tell they seem good.

While installing the solenoid valve I lost the little black plastic cap that fits over the small circular protrusion (red circle in photo). Am I correct that this needs to be covered in order to develop the vacuum in the lines for the PSE to function properly? Can I simply tape it up or is there something else I should know? If it should be sealed, maybe someone knows what its there for in the first place.



Thanks in advance.