boost gauge fitting, HELP

ok, i attempted to fit my boost gauge.

i t bar'd in a pipe off the left side of my manifold. run the pipe from the engine bay into car and connected it to a sorat electron recieved that the pipe fits to. this recieved has a live, earth and green (think sender wire)

i then wired in my gauge, red to live, black to earth yellow to switch live and green to green sender wire.

started car and gauge does a self check and the travelled to zero. it then lifeted to a minus figure on gauge and held it.

when i checked on the pipe from the manifold it was all tight, all air had been sucked out like a vacum. (dunno if thats right)

i went for a quick blast and the guage didnt move, yet, if i detach green sender wire the gauge goes over to 2 bar position as if back in test??

dunno if it me, or the gauge

if possible can some send me a pic of there the plummed in their boost gauge

and if any1 can shed any light on the small reviever / sender unit that the pipe goes into.

heres a fews pics, gauges, the wires and where i plumbed into.

From what I can make out, it doesn't need to be teed off at all.
That pipe that comes of the manifold, goes straight to the sender.
Thats how the electrical type boost gauges work.

In the 3rd pic, where you have the t-pieced pipe, just underneath where that is connected, its a plastic cover. Pull it off, and put the vaccum hose there, direct into the sender unit. You then wire the send into a live and earth, and then the sender into the boost gauge.