2008 4 motion 2.5 BPC Boost issue

[Infrogneto]

Well what have I done!
Yes I bought it with the issue and these are the symptoms...
It's ok on the flat and turbo can kick in a bit on slight deceleration.
It can be made to work if you tap the pedal and voosh! then you leave a big black cloud behind you!
Basically cant do hills just no turbo at all getting worse..
Can somehow be better in wet weather..
Glow plug light flash amber comes on bottom of hills which I have read indicates boost issue..
Oil coming from turbo now and also oil filler neck base, intercooler pipes full of oil, seems not breathing well, is it the PCV?
Seems one thing leads to another I suppose...
Previous owner gave up going to many places spending many dollars, no one seemed to want to go balls deep and get their hands dirty just replacing little things and reflashing software etc.
It has 300k but I love it and its the perfect long term vehicle for me, I don't mind getting in and doing things myself..

[Greg Roles]

Sounds like the turbo is shot, you can get a new turbo core out of Mamba pretty cheap, I have one on hand actually I don't need ( I'm in Aura ), bought it "just in case" although my own turbo seems to be running strong so it's not needed. I'm selling my van as it's just not getting used, so you are welcome to it for say half what it cost ( $500 out of UK ). You'll need a VAG experienced mechanic to fit it, I'd recommend Andy at Elite European at Kunda park, he's a great guy, not a rip off, and highly recommended. Actually Andy could error code read it too.

It may have EGR/DPF issues, my EGR was totally caked and leaking at 270 thou, and I have a Darkside EGR delete and DPF delete pipe not being used if you need to fix any of those errors, I returned it to stock to sell it. Will need an ECU flash to delete those however, but boy does it go well without the restrictions! If manual you can tune for more performance, if auto best not add power as auto box near limit stock. Error codes will help diagnose.

If you take the airbox lid off do you have any blowback pulsing, as cam wear is a common issue in higher mileage 2.5's and causes all sorts of issues.

There are a few things it could be, first step is error codes, then working out cost effective ways to sort it, but once you get them fixed and stay on top of the service requirements it's a panzer tank of an engine.

[Sunny43.5]

Add to Gregs post , when ours was giving trouble we found a vacuum hose with a small split which was the cause of ours not boosting and then going into a limp mode . It was fine in some driving but out of the blue it would go into limp mode.

[Infrogneto]

Howdy Greg,
I have read all of your posts on fun times with the BPC, Looks like I'll have to come visit as I'm in Aura daily and work nearby.
It's a manual, I just sold the exact van in 2wd with DPF delete EGR block remap and it went hard but need 4 motion so here I am.
Also bought a complete Caravelle with BNZ 2.5 for spares...
Previous owner said DPF has been removed apparently... yet to confirm, also had cam and lifters done just before I Bought it.
I'll go see Andy asap for a plug n read the codes.
Super keen to get it sorted thanks for your help and I'm pretty keen on the parts too, not sure if i can message you yet?

Sunny43.5 Thanks for the tip,I'll get all hoses tested!

[Infrogneto]

*Update*
Turns out previous owner had a new but non genuine N75 valve installed so every one from there on kept looking for problems in other places... So when it comes to certain replacement parts GO GENUINE VW!
It's still not 100% bit slow in low rpm.. I know how hard BPC can go owning one previously but sure a **** a whole lot better as I can hammer up hills again and overtake on the highway!!!

[Lucas_R]

Sounds like a decent win on the N75 valve - definitely worth only buying genuine or top quality OEM manufacturer for certain parts. Perhaps look into doing a smoke test to see if you have any boost leaks and you might find the other 20% you are missing.

[Infrogneto]

I've been wondering as it's still not right... what are the signs of a turbo "On it's way out"... . Low down rpm almost nothing... like when you need it taking off at the lights first & second gear... seems to only kick in after halfway or have to tap the gas pedal on & off ...
The new n75 valve fixed the top end rpm problem but what makes it feel sticky in the first windup bit?
I know how they shoud go after owning a few BPC's .. do I need a new or reco turbo? What else makes the first bit "kick in"?
Not an easy task to just pop another turbo in as it's a 4 motion ...

[Greg Roles]

I've been wondering as it's still not right... what are the signs of a turbo "On it's way out"... . Low down rpm almost nothing... like when you need it taking off at the lights first & second gear... seems to only kick in after halfway or have to tap the gas pedal on & off ...
The new n75 valve fixed the top end rpm problem but what makes it feel sticky in the first windup bit?
I know how they shoud go after owning a few BPC's .. do I need a new or reco turbo? What else makes the first bit "kick in"?
Not an easy task to just pop another turbo in as it's a 4 motion ...

Sadly could be a ton of reasons for turbo lag on the BPC, mine isn't a rocket below 2000 rpm, but sure goes once you rev it. Was your prior van 2wd? The four motion extra drag/weight will kill the response a fair bit, and if you had a DPF delete on your prior van it would have been far more responsive if your current van sill has a core. I'd suggest further visits to Andy the VAG mechanic for vac and turbo actuator rod testing, will cost but chasing these sorts of problems can do your head in if you don't have the know how and tools.

I have a new Mamba CHRA hybrid turbo core if you need it, was just going in the spares box to sell with the van. It's China, but they seem to be holding up in the XR6 crowd. It has a hybrid inlet impeller for a bit more grunt. Cost me about $400 from memory, will sell for a fraction of that if you are stuck.

[Infrogneto]

G'day Greg, I took it to Andy recently having a decent oil leak from the turbo seal asked him to check out the turbo while it was out not sure if he really went all over it though so cant rule it out.
Yes my first BPC was 2wd no dpf and 1st stage tune = went hard...
This BPC 4motion has no dpf and has the problem = lame in low rpm
Also bought another BPC 4motion still has dpf = goes nice all the way through rpm so I have this to compare.
Thanks for your reply, I'd be keen to check out any bits you have before you sell.. Say when is a good time to drop by, I sent you a PM.

[Rebuild]

If theres a ton of oil, you can take off the intake pipe to the turbo and check for slop in the bearings/ wear marks on the housing.Think i removed the airbox when i looked at mine long ago. Turbo had a little slop

Or jack it up safely and remove the outlet pipe 5mm allen key only

Saying all that, mine seems a bit down on mid oomph lately too (maybe 1800-2400 rpm). A hilly freeway i used to do comfortably in 6th, now seems to require 5th.Once the turbos up and going topend seems fine.Blanked off the EGR ages ago. 200K km

Gonna check it again soon. I have some oil in the pipework but not a lot.It's not using oil between changes.