"jet engine" sound on acceleration

[bbach7]

No luck with the search so...

After routine changing of injectors and installation of a new water pump on my 1991 300D 2.5T, I get a very strange sound upon acceleration.

The sound is there only when the car is in gear, and only when I am "pushing" the acceleration. It sound just like a jet engine spooling up and is quite loud.

The sound goes away whenever I back off the accelerator. At first I thought it might be the turbo, but the sound is more "generalized" and seems to come from everywhere.

Car shifts fine. Turbo spools properly. Everything is great except for the shreik under load.

I've read about possible pinholes in the exaust, but I wanted to see if there were any similar experiences or ideas.

Many thanks in advance!

[bbach7]

After a thorough inspection, I discovered that one of the bolts securing the charge air pipe to the manifold was not quite tight.

After tightening this properly, the sound went away.

Per usual, operator error.

Just fyi.