My 98 s70 M56 turbo car would not start without jumping the starter relay. Kept messing around, new ignition switch but to no avail. Caught this post and simply wired the relay lug #85 to ground and BINGO everything is working again! Many thanks to those that contribute......... It is ugly, fast, an...

Sounds like it is not hooked up correctly. recheck the hose connections based on the installation instructions.........ask me how I know!
Also, the wastegate adjustment may be too tight if it flutters.