[xsiv]

Its easy to problem to solve... the boost is either not being made or it is venting somewhere.

Start simple - check all the intercooler pipes - make sure none are disconnected. Check blow off valve and see that its not broken or a vaccum line is not disconected and venting boost straight out. Check everything all the way to the manifold for leaks.

If that does not solve the problem the next likely cause is the exhaust gas is bypassing the turbo - usually from the wastegate or actuator - either being stuck open - remove and/or check that the actuator is closing and opening or possibly if running an external it is missing the steal O ring - remove and check.

Failing this the turbine wheels may be damaged -