Ive been in the turbocharger industry for 28 years now. Fault finding is the biggest factor when diagnosing turbocharger problems. Many technicians get this wrong.
With the introduction of VNT turbo technology, turbos have become more involved , but can be repaired very successfully as long as the testing equipment is available, and I have both VSR balancing and actuator testing and setting facilities.
the turbo shop
listed some of my websites can be found at http://resteasy.co.za