sounds like a dual port actuator? one port will open the waistgate when boost is applied once it overcomes the spring pressure.., the other usually has a air regulator so you can add pressure to the back side of the diaphram to keep the waistgate closed longer, which will achieve more boost..
here is my description from another forum..
i use a dual port actuator and a "mini air regulator $15 ", i replaced the stock 100 psi spring in the regulator with a 30+- lbs spring (freebie) same size just thinner /weaker so it is less sensitive ..
so 1 turn equals about 1lbs of boost instead of 1/2 turn being 10 lbs.. it is a bit progressive ...but works slick 
this lets me add pressure to the back side of the waist gate actuator and keep the swing valve closed longer for more boost on top of the 7.5 lbs spring of the actuator..
i added in a air switch {flow, or no flow} between the regulator and the backside of the actuator. This so i can keep the regulator set at higher boost and turn the air switch to stop flow so its just the 7.5 lbs of boost off the actuator spring... nice for first and second gears launches where higher boost will break tires loose..3rd gear flick the switch and your at full boost..
if you dont have a dual port , they make some nice bleeder valves but they should be mounted under the hood i think???. short as possible.. and there like 25$ on ebay.. that's my manual controller.. 
EVERY THING ELSE IS JUST A BLEEDER...