Noisy Turbo?

[johnniebiker]

Hi Guys, I'm new to this forum but like most, I think, i have a problem that needs some expert help.

I have a MK4 Golf GTI 1.8t AUM with 70000 miles.

I "booted" the car down a long straight on the way to work. On deceleration it seemed a bit lumpy. When I came out of work 8hrs later, it was very reluctant to start and when it did, it was sputtering and farting and not running well at all. There was also a whining noise that sounded like a cam belt idler wheel bearing....
After a while the lumpiness cleared and engine is running perfect except for the whining noise. Turns out the noise is coming from the turbo area. If I open the waste gate by hand the noise seems to disappear or get quieter at least. The weirdest thing is it is going quicker than it ever has! I should mention it was mapped by Black Code 2 years ago.

So the symptoms are, whining noise coming from Turbo, faster performance than normal, no lumpiness or other performance issues. 17705 code. The whining noise comes in about 1500 to 2000 rpm then fades to the normal turbo noise comes in but is is louder than it was before, like it is on permanent full boost.

I am looking to take it for diagnostics, so clutching at straws before I do commit to that.

Any help is much appreciated.

Thanks,

John

[johnniebiker]

Update,

I have changed an engine breather that had a hole in it and even though the code 17705 has now gone, the whine is still there. I'm now getting a code 17840, after I've been "trouble shooting" so this might be self induced.

Thanks again,

John

[zollaf]

wastegate not opening.

[johnniebiker]

wastegate not opening.
Thanks Zollaf.
Yes, possibly. But why? I've function checked the wastegate actuator and that seems ok. N75 seems to work. I can't find any other leaks. It's a mystery. Maybe it is the turbo itself, but the car is super quick and there are no other issues?
Thanks, John

[zollaf]

i dont know why, its just a hunch. cars super quick, well it will be if the wastegate isn't opening as it will be over boosting. maybe the ecu isnt telling it to open, maybe the map sensor isnt working , needs some diagnostics doing other than just looking at codes, but if i am right and you keep on driving it you will end up detonating the engine.

[johnniebiker]

Yeah, I kind of guessed that. I have got it booked for diagnostics. It would just have been nice to work out what happened. Thanks for your thoughts though. John