As ive previously said turbos generally still produce even when massively screwed, so somthing very obvious will be wrong with it. i'd take the turbo off and check that the shaft turns(inlet hose off first to try to turn it by hand is first easiest step), if it doesnt then maybe part of the washer has jammed the turbo. you'll need to remove the bolts securing the clamps on the turbine housing and remove very carefully. check the turbine for any damage,bent fins from the foreign object.