Turbo spooling waaaaaay high!, need boost to come down......how?????? Options

[injection]

Hello doctors, get your surgical gloves on, because i need help.....
i have asked this question before with no solutions, so i will try again, maybe someone will pick up something i missed, hopefully!!!!!
basically, my 94 celica gt, which i swapped a st205 into, was up and running last may ( 2011 ), ever since then, my boost climbs to around 19-20psi, i have hit fuel cut twice, and smacked my face into the windshield the first time ( seatbelt safety ),
anyways, in order to stop hitting fuel cut, i have to let off around 5500-5700rpms, because im right on 18psi, and dont want to keep hitting fuel cut....cant be good
so heres what ive trouble shooted so far:
hooked air compressor up to wastegate with 15psi pressure....opened perfectly, quickly and smoothly
have an XS Power DP, checked to make sure the actuator clears the DP flange....it does
there is a line that comes off the wastegate and goes behind the bottom of the intake manifold to a sensor called a VSV valve???? i think its called, anyways, hoses are hooked to that and return up front, cant remember where the line goes up front though??
thats about it, kinda outta ideas

I was thinking of purchasing a manuel boost controller, but isnt that for turning up boost, or can you turn down boost as well ( explain please )
If that doesnt work....is there some sort of a bleeder type valve i can buy, to vent some pressure, or does that screw-up vaccum

Thanx, hope one or alot of you have an answer to my problem 6GC

[ST205WRC]

ok i think most things have been hit but not in any detail to actually help you solve the problem other then just get a boost controller. assuming all hoses are connected correctly, as neon said yes the 205 is extremely prone to boost creep, WHEN you have a 3" downpipe and exhaust. most downpipes available (except Berk Tech) sometimes have problem with the wastegate port opening all the way i know you said u checked if it cleared the flange but they have problems hitting the inside, so i would check to see if there is any marks in the carbon on the inside of the DP to see if its making contact. most guys on alltrac.net will say that a 2.5" DP and 3" exhaust is the preferred setup for a street use/stock turbo setup. if the wastegate IS opening all the way and you have 3" all the way back then you can either go smaller with the DP or put a reducer at the end of the DP. my car does the same thing except it holds strong at 1.1bar (just under 18psi) if its cold or i get on it real hard you can see the needle on my boost gauge bouncy back and forth as the wastegate is trying to keep up. in the end yes you can get a boost controller and it should help with the problem.