2. 0 tdi brd boost loss

[Gez470]

Hi, suffering from the dredded P0299 and only had a new turbo fitted about 12 months ago, the periodic limp mode has been an issue with the car before and after the new turbo (turbo change was due to it being blown out of the exhaust 🙄). Upon checking the pipe going into the throttle body, or whatever audi call it, it seems very loose for something that is meant to hold vacumm. Can anyone let me know if this pipe is meant to be solid attached to the body? I have pulled the clip, removed and tried reaseating and coulnt see if there was a perished gasket or anything.
Hope I can get this sorted!
Thanks
Gez

[Crasher]

16683 (P0299) - Boost Pressure Regulation: Control Range Not Reached
That is underboost and normally a leak in the vacuum control system, if you apply suction to the 3mm vacuum source line to the servo pipe you should have an air tight circuit, if you can draw air, work along the hose with flat face pliers closing the hoses until you find the leak. One chap recently had the fuel cooler diaphragm leak causing him this problem for years but that is only on very early 3B Passat with a 1.9PD.

[Gez470]

Worth ordering a vacumm pump from amazon to test? Or literally just suck it and see?
I'm wondering if a leak in the intake manifold would cause this? As I see allot of oil underneath the manifold, either that gasket or one of the seals between the pile from the intercooler to the anti shudder valve? I'll try and get. A picture tomorrow.
Thanks

[Crasher]

The vacuum system on a diesel does not come from the inlet manifold as there is no depression, it is provided by the tandem pump on the head.

[Gez470]

Understood.
I have ordered a vacumm pump from amazon so I can check the lines tomorrow hopefully.
Also ordered intake, egr and anti shudder valve gasket. They seem easy to replace and the oil below there must be coming from somewhere :)
Car doesn't seem to be using oil, so hopefully it's old oil from the old turbo, don't think the mechanic cleaned out the intercooler system of oil, and in guessing some oil gets through even a good turbo.
I get thick black smoke on heavy acceleration, with the oil level not dropping im guessing its over fueling due to boost leak, with an average of 35mpg it seems high.
Thanks for the help, you seem to help allot of people on this forum, I appreciate it.
Thanks
Gez

[Crasher]

The black smoke is due to boost pressure loss so the combustion process cannot make fuel use of the injected fuel so as you drive by, small children fall to their knees clutching their throats in coughing fits and plants wilt..... but less Co2 so less global warming from transport Co2, maybe....

[Gez470]

OK tested the vacumm lines from the pump into the one way valve, it's pulling 22 inhg, and the line from the valve onwards is holding a vacum for at least 60 seconds. I'm guessing that's enough, the line from near the altinator down towards the turbo is neither pulling OR holding any vacumm either way, does that sound correct?
Thanks
Gez

[Crasher]

That could be a leaking N75 valve.

[Gez470]

So as I understand all actuators should move when vaccum is applied and not leak? The easiest one to get to is next to the altinator and seems to have arod into the head, this does not actuate or or any type of vaccum, what is this one called? Inlet manifold actuator?
I'll trace the pipe down towards the turbo tomorrow when I have more time and light, I'm guessing I'll find the hose leading to the N75 valve and then to the turbo actuator? Would I need to get underneath the car for this :)
Thanks for the quick replies
Gez

[Gez470]

OK so the swirl flap actuator is fubar, the line to the actuator is all good, the line to the turbo is all good and the turbo actuator is all good. Ordered new gaskets and new swirl flap actuator (apparently audi only sell them attached to the manifold for £750) and should all be here for the weekend with a bottle of Mr muscle and some petrol! Nice messy job for me, hopefully this sorts it. Does the engine have a swirl flap sensor or anything? Because I would have thought it not matching up with the required movement would throw an error code of its own 🤔