On my boost solenoid...the first plastic piece in the picture has broken off and only the top port is capped, for right now I have some rubber hose covering the hole and zip tied... can these be left open or does it absolutely need to be capped?

Thank

 

Well the Top is the Boost source from the Turbo and the Other one opens the wastegate so you may have no boost control.

 

Im using a Forge MBC also