E60: Turbo whine and no boost!

With the engine-swap teething problems put to rest and the car back on the road [at last!], there was bound to be a few running faults. All in all its going like a dream, though I would say the engine is a lot noisier and vibrates more than before. This could mainly be due to the lack of acoustic-covers and under-trays as I iron out defects, but not entirely so I will have to look at the pneumatic engine-mounts when I have time.

When I got the car out for a good run, the main problem I notice is a serious lack of boost. The turbo is also making a low-pitch whining noise, which sounds a bit like a police siren. I read that this is the noise of a dying turbo, though I find this a little hard to swallow as it was fine before and I see no reason how being removed from the car for 3 weeks would affect it. Far more likely that I've messed up attaching some vac-line or wire-connector, or lets hope so anyway. It's an annoying whistle, as it can only be heard while driving under load and not when revving at a stop.

• Turbo can be seen spinning.
• No front-rear play on spindle-shaft, hardly any left-right play.
• Pipes from turbo to intercooler and intercooler to inlet OK.
• Removed and cleaned air-temp. sensor.
• Some boost air is coming from the intercooler outlet.

Before I diagnose a dead turbo and start spending any more money, I will check the vacuum lines meticulously and also re-check the pipes for splits. The turbo also needs looking at, from the oil-feed to how it's fitting the manifold. The waste-gate doesn't seem to be operating and that seems a bit too serious to be caused by such a small vac-line fault. Ho hum, the saga continues...