vtecgsr95

i have checked all vacuum lines and connections and everything is where it is suposed to be and nothing leaking. I have bypassed the pre control and turbo control solenoids and installed MBC in their place per the diagrams available using the search function.
I get great primary boost, but it seems to fall off quickly. Then, I have no seconday boost UNLESS I hammer it in first (no secondary in 1st) and powershift to second.....then she holds 12psi to redline without twitching!! I dont understand why it only works when I hammer it and power shift? I was thinking if there was a solenoid problem it wouldnt work at all! The vacuum lines have been checked and were all replaced with silicone already! BTW, mods are: 93 stock twins, ported WG, DP, hollowed stock MP, and 3" CB, HKS intakes, all emissions and a/c removed, XS power I/C, and Pettit ECU. Any thoughts from the pro's??

Ibumar

Check valve to pressure chamber maybe?
I would check pressure and vac chambers and associated check valves first. Starting with the one mentioned above.

Also check this link for procedures to solve boost problems. Very helpful page.
http://www.autosportracetech.com/RX-7/rx7stuff.htm

Good luck