Turbo Carbon!

ben0069

Well-known member
Joined
Oct 15, 2012
Location
wales
TDI
allroad 2.5 tdi v6
My turbo is getting really carbonated after about 1500 miles of driving, to the point where the vnt is hardly able to move at all, is this a fuel issue or an oil issue ?
Mpg's are good, power is good, no visible blue smoke, Injectors are newish with dsla143 p970 nozzles, I did a compression test which showed 420psi /29 bar across all cylinders, but it is using a little oil.
where should I start?
 
Last edited:

ben0069

Well-known member
Joined
Oct 15, 2012
Location
wales
TDI
allroad 2.5 tdi v6
2.5 tdi v6 bau engine code, sorry I should have said stock injectors with bosch nozzles.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
What type, just soot? Or is it hard sticky "oily"
What is your driving habit?
How are you checking? Could it be a worn actuator or low vacuum that not helping?
 

ben0069

Well-known member
Joined
Oct 15, 2012
Location
wales
TDI
allroad 2.5 tdi v6
it seems like damp soot, not oily.
Driving habit is spirited.
After a certain amount of time/miles The vnt is unable to close, this is quite audible and there is a lack of power(no boost) while this is happening, after a minute or so of driving it slowly then seems to build boost again and it's fine for a short time. Once this happens I know that the turbo is getting sooted up.
actuator is new and last time I checked vacuum it was fine.
 

Mongler98

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Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
It could be from excessive oil vapor.
You could try putting a proper sized catch can in line for the CCV to the intake pipe. You could DIY it for now with a monster can and some vynil hose.
If it's not helping... then maybe it's something else.
Typically a failing turbo will cause extra oil loss. Have you noticed any extra oil consumption?
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
To the best of my knowledge, all VE TDIs use DSLA 150 injectors, the number is the included angle of the spray in degrees. The number you gave has a 143° angle and is used in Cummins and other truck common rail Diesels, which yours is neither. The spray angle is closely engineered with the piston bowl geometry and inlet swirl. This alone may not be the root cause of the sticking vanes (through excessive smoke) but might be a contributing factor, the oil consumption can be another (how much, precisely?). If Wales does something like MOT inspections, I'm curious about the exhaust smoke result.
 

adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
You tried for vacuum leaks Ben ? Its unusual to get the turbo clogged like that with no visible smoke either black or blue...Is the n75 new ? I would also look at simplifying the vacuum and remove the tee to the anti shudder valve, there is a joint under/round the ABS pump which goes to the vacuum accumulator, check if thats sound.
 

ben0069

Well-known member
Joined
Oct 15, 2012
Location
wales
TDI
allroad 2.5 tdi v6
stock nozzles are 142 degrees, I don't have excessive smoke.
I have replenished all vacuum lines, n75 is newish. The anti shudder valve, is that just for engine shut down ?
I will pull injectors and send them for testing...
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
If you dont have massive smoke issues.... it's probably an oil issue.
However... seeing as your Injection may be suspect it does make sense. Your situation may be that the wrong or bad nozzles are just not getting enough fuel burnt to get high enough EGTs to burn off what normally gets in there.
Best way to burn off oil and carbon junk is with heat.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
That is good to hear, but the vnt is literally jammed !
The issue is not the soot. It is a mechanical problem. Have you actually tested the amount of vacuum your car is producing?
 

ben0069

Well-known member
Joined
Oct 15, 2012
Location
wales
TDI
allroad 2.5 tdi v6
The issue is not the soot. It is a mechanical problem. Have you actually tested the amount of vacuum your car is producing?
No, I have not tested the amount of vacuum. When the turbo is cleaned the car runs perfectly, it holds boost all through the gears, It has no issues until a certain amount of driving/miles has passed only then it starts sticking, if I remove the ring that connects all the individual vanes each vane takes quite a lot of force before it breaks loose again and even then they are dragging and not free moving.

Turbo has gone back to shop and injectors have gone back to be inspected too...
 

adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
Probably the vnt mechanism is sticky…had a few with some wear that were hard to move and would trigger limp mode when that happened…
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Yea. Probably is a rust/ clearance issue. Like everything might need to be polished. Then assembled.
I'm out of ideas but I'm no turbo guru. But I can tell you its not a carbon issue maybe that's what's causing the other issue to appear but that level is actually very clean!
 

adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
Send it back to adam to have a look at it, he will Suss it out if he opens it up ! I am surprised you’re still keeping the old girl and have not upgraded as most of us do…
 

Nevada_TDI

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Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
It wouldn't hurt to take the control ring apart and polish all the contact parts with fine Emory cloth, the lesser friction helps to prevent premature sticky vanes.
 

diffas

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Jun 25, 2008
Location
Finland
TDI
B5q A4 Avant 2.5TDi+, B7q A4 Avant 3.0TDi
I had once similar issue and the clearance between the vnt vanes and the turbine housing was too tight and soot jams it bit. Solution was to pull vnt off and make some sweeps on fine grindingpaper.

And for the tdimeister not all tdis use 150angle nozzleangle.
 

ben0069

Well-known member
Joined
Oct 15, 2012
Location
wales
TDI
allroad 2.5 tdi v6
Turbo is back rebuilt and tested, not mounted yet, injectors are back from united diesels all were working fine. Fuel pump has now been returned to be changed back from 3 plunger to 2.
Only a smear of oil in intake track.
 

ben0069

Well-known member
Joined
Oct 15, 2012
Location
wales
TDI
allroad 2.5 tdi v6
Wouldn’t be easier to get another pump rebuilt instead of messing the 3 plunger one ?
maybe, it feels like something just isn't right, when I had 2 plunger and cpc nozzles +66% I had 280 hp, but now with 3 plunger and p970 nozzles I only have 220hp the pump I have is almost new and if that is the problem then it will be a relief, as for the turbo, it had new chra and vnt mech last year so it was just cleaned up.
 

diffas

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Jun 25, 2008
Location
Finland
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B5q A4 Avant 2.5TDi+, B7q A4 Avant 3.0TDi
Well if you put 40% smaller nozzles and make no changes to ecu of course output power will be less.
 
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