Rattle from turbo!!

[themodifiedkid]

Hi, (I posted this up earlier in the wrong section, so apologies for the repeat!!!)

I finally got around to replacing my turbos as the front one had chipped fins and was affecting performance.

Anyway I took it out for a spin to check everything was ok and it was boosting okish up to just over 1 bar for a brief moment then was drop straight back to about .7 -.8 bar and just didn't feel as quick as I remembered and also wasn't getting that "rush" at 4000 rpm when the second turbo comes online. Now I assumed it must have been a boost leak so took it home and roughly checked pipe work and seemed to be ok, so I thought I'd put it into the temporary ttc mode where you bypass the IACV VSV and bypass the EGCV VSV to try and eliminate any possible problems with the vsv's.

 

So after doing this I started the engine and straight away there was a metallic rattling sound coming from the turbo area, sound more like it was coming from the first turbo, as if something loose somewhere rattling around. Now I then pulled the vaccum hose from the EGCV actuator ( the big one that sits under the whole turbo "gubbings"!! And immediately the rattling stopped. What would cause this? Any help would be much appreciated as I haven't driven the car properly for nearly 3 years as have been doing bits and pieces to it and would really like to now just use and enjoy it again!! It's fully bpu auto.

Also it doesn't rattle at all when in sequential mode. I'm hoping it's only caused by a boost leak so I don't have to end up stripping it all down again, but how would a boost leak cause this rattling?

 

Thanks