Hdi Ebc Type-d Se Help

[93R33gtst]

i had excatly the same problem what ur having and it puzzled me. i ordered the boost gauge with the controller and had a fluctuating guage and it would always be powered when i hit my mircotechs boost cut. the problem was the earth i had and u probably do as well is a poor earth, try changing it directly to the chassis or another wire.
another thing that will help with the boost is run an individual line for the controller and an individual vac line for the soloneid. dont use the line of the fuel pressure reg as it is a smaller line. and use new vac line if possible. hope it work out

Im installing one oF these currently and im not sure which ports on the solenoid to use and to i plug up the third one and how to plumb it in for a skyline