just helped my friend put a sohc vtec in a 91 si,have a couple questions:

i need to know if i can just tap into the oil pressure sensor on the back of the block for a non-vtec to v-tec swap on a 91 civic si- heres the setup
91 civic hb si
92 civic d16 vtec swap
91 si non vtec ecu
vafc
i need to get the vtm wire and i'm finised i just dont know how to get a proper signal
also , will this thing engage vtec on its own without a signal from the ecu ?
and lastly, on the solenoid for vtec there's 3 plugs
1 comes from the plunger looking device w/1 pin
the other is on the solenoid itself with 2 pins , is this solenoid input and ground or something else
thanks for the help in advance

 

*sigh*