VNT Turbo dead...bad luck or check XYZ?

sassercollins

Active member
Joined
Aug 21, 2006
Location
here and there
TDI
2000 Beloved Golf, 4 Door, MK4 (AHL)
Two years ago I bought a new VNT Turbo for my car as I was in this space of wanting to jack my car. I got new injectors and deleted the EGR and got a Stage Two Malone tune and thought I was going to have a better car that was more responsive and faster.
I wish I had my old stock car back at this point, as my newish (<15k miles) VNT Turbo died today. I was getting positive deviation codes there for a while, had a shop adjust the actuator and then all was good. One day the car feels gutless and check engine light comes on. Negative Deviation now :(
Shop says the turbo vanes are worn and not spinning. I bought a new turbo and will install, but I am curious if there is something that is causing this?
I've drained my intercooler, which didn't have much to drain at all, maybe a teaspoon of oilish liquid.
Is there something else I should be checking? It seems a new turbo should last longer than 15,000 miles! I bought new from ID Parts for several hundred dollars. makes me sick.
Thoughts?
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Was it not more responsive and faster after the tune?
Far as I know, ID does not sell any of those el cheapo turbochargers, the unit you bought should go 300,000 miles easy.
Only thing I can think of is lack of oil, but there must be other things to wear out the vanes that quick.
 

burn_your_money

Veteran Member
Joined
Oct 16, 2012
Location
Missouri
TDI
99 Beetle, 96 B4V, 05 Passat wagon
Do you drive your car hard every now and again?

How much vacuum to move the vanes and how much to hit full stop? Is your car producing this much vacuum consistently?
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
If you don't have a vacuum source--Mity-vac--or the equivalent get one and check the turbo actuator yourself. Generally speaking, if the turbo died you would have suffered a huge loss of oil. What is your oil level, is it close to full as it should be?
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Shop says the turbo vanes are worn and not spinning.
This isn't really a diagnosis. The vanes in the turbo don't spin. They close the chamber to make boost. The impeller spins. It only should be handling air so the blades (not vanes) on the impeller shouldn't be worn. If they have been damaged by something that's not supposed to be in there (dirt or carbon chunks, for example) that's another story.

Turbos should last several hundred thousand miles. My son's 02 Golf has 362K on it...and the original turbo. You could have carbon build up, a vacuum problem, rusted actuator (especially if you don't have a belly pan on the car and live where roads are salted), but those are all easily and pretty inexpensively fixed. Or you could have a clogged intake. Or a bad MAF.

I'd do some further diagnosis before concluding the turbo needs replacing.
 

Dieselmonkey02

Veteran Member
Joined
Dec 26, 2011
Location
Edinburg, Pa
TDI
02 jetta
Check your vacuum from the pump. Leaky vacuum lines will make it a dog for sure. So will a bad MAF sensor. A clogged fuel filter etc etc. I can’t see a turbo taking a dump in 15k unless it was severely abused.
 

Owain@malonetuning

Associate Vendor , w/Business number
Joined
Jul 1, 2016
Location
Vancouver
TDI
PD jetta wagon
I'd do some further diagnosis before concluding the turbo needs replacing.
X2. There are plenty of people out there heavily abusing them rolling coal running 20+ PSI, these are very stout turbos. Stage 2 tune is set at 18 psi and not overly aggressive, sounds more like an install issue.

I would personally invest in a rosstech cable and mityvac. Actuator adjustments shouldn't be done unless the car has been data logged first to show that boost is not following what the turbo requests.

http://www.myturbodiesel.com/wiki/v...ustment-repair-replacement-on-tdi-engine-mk4/

You can find a bunch of example logs here, block 11 is boost
http://log.malonetuning.com/search?partnumber=012bd

This is a more modified vehicle, but you want actual boost pressure to follow request smoothly and within 200mbar or so
http://log.malonetuning.com/chart/33477
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
Is there something else I should be checking? It seems a new turbo should last longer than 15,000 miles! I bought new from ID Parts for several hundred dollars. makes me sick.
Thoughts?
I'm doubtful the new turbo is bad but not ruling it out.

I would check if the vacuum pump is producing at least 20 inches of vacuum at idle. The actuator needs 18 to open fully.

You need a vacuum pump to test if the actuator is holding vacuum.
Also with the vacuum pump you need to connect it to the line going to the actuator. It should start moving the arm at 4 inches and be fully down at 18 or so. It should also move smoothly through the travel.

Next, tee into the vacuum line going to the actuator with the vacuum gauge.
When you start the car you should get 10 inches (or so) vacuum there. When you start to drive it should drop off a bit.
 

sassercollins

Active member
Joined
Aug 21, 2006
Location
here and there
TDI
2000 Beloved Golf, 4 Door, MK4 (AHL)
Thank you everyone for the thoughts. I do have a rosstech, though I am not very proficient at using it. I will do some logs and see where that takes me.
I checked out a vacuum gauge from AutoZone and all the vacuum lines held vacuum (I've replaced those also in the last 15k).
BobnOH. My car was very responsive after the tune. But I got the tune done years ago, before the new turbo.
burn_your_money. I drive my car hard. I love the tune (when the rest of the car is working) and drive it as such. Somewhere along the way the system just couldn't hold up.
Nevada_TDI Interesting...I had no loss of oil. The actuator moves but not as far as I think it should, but those things have always stumped me and so anything to do with those actuators I end up having to pay a shop to look at. I just had a shop adjust it last year due to the positive deviation code, which ended up fixing the issue...but now I have a negative deviation. (sigh)
IndigoBlueWagon.. My thoughts precisely. And now that I paid the shop for the diagnosis I am feeling like they didn't really dial it down and left me thinking it was a turbo issue. "Just throw parts at it" mentality really get me. It is difficult to find competent mechanics who would work on my modified vehicle/TDI/WV.
Dieselmonkey02.. The vacuum lines all hold up, and the MAF sensor was recently replaced also...back when I was chasing my positive deviation.
wonneber..."Also with the vacuum pump you need to connect it to the line going to the actuator. It should start moving the arm at 4 inches and be fully down at 18 or so." Really?! Maybe this is my area to focus on, as my actuator didn't move until about 15 and only moved about a 1/2 inch. When I connected the gauge to the end where the actuator would be, the gauge tested ~12. Does that signal a bad actuator?
I really appreciate this forum and everyone who offers their advise. I appreciate you!
 
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sassercollins

Active member
Joined
Aug 21, 2006
Location
here and there
TDI
2000 Beloved Golf, 4 Door, MK4 (AHL)
Update: Last night I went after that actuator and finally got it off the turbo and set it on my windshield while I performed the vagcom/rosstech 011 test. The actuator, upon initiation of the N75, starts to move fully 1, 2, times and then starts to loose full range of motion slowly to the point of not moving at all and the test is still running.
I am not sure, but I don't think the test performs in a decreasing manner like this. I did test the actuator with the vacuum gauge (last week) and it held vacuum, so I am suspecting it is something in the N75 or hose between the actuator and the N75 that is causing the decay of vacuum? Anyone help me understand if my suspicion is correct?
 

JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
In my experience the N75 tends to accumulate crud from a rusted actuator. Take it off and see if any loose debris falls out; mine did.
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
Now that the actuator is off the car it should be easy to verify if the turbo arm is moving through its full travel. Does the actuator arm move all the way from stop to stop? Is there any feeling of grit or does it feel "notchy" when it moves? That would be the next thing I checked for if you haven't already.
 

Dieselmonkey02

Veteran Member
Joined
Dec 26, 2011
Location
Edinburg, Pa
TDI
02 jetta
If the inside of the can has pack rust/ dirt accumulated it could stop moving as it moves around. Try moving it by hand and see if it feels “crunchy “.
 

sassercollins

Active member
Joined
Aug 21, 2006
Location
here and there
TDI
2000 Beloved Golf, 4 Door, MK4 (AHL)
The Turbo arm moves great. The actuator is not rusty or clunky and feels new. So I put the car back together and the actuator arm had to be shortened for me to fit it back on. I figured I would adjust it as needed after I got the thing on.
I took it for a drive and I had my old car back! It was amazing. Fast, responsive from stop to go. I could pull out in front of cars going 50 and speed up with confidence. I wish this was the happy ending...but I drove about 100 miles today on the interstate and I was speeding with lots of power through 90mph. I got back on the interstate on a steep, fast onramp and something happened. The car went gutless on me again, droney, and barely able to make 60 uphill and no more than 73 mph on flat ground. Soon the check engine light came back on. I checked and its P1556: Negative Deviation. JBO5 I just checked the N75 and it does not have anything loose rattling around and feels solid. I am thinking it has to be a vacuum issue, right?
I'd love to see a video on how the N75, actuator and vacuum system work, but I can't find one. I am curious what is happening to the N75/vacuum in a 0-60 mph, uphill situation. Can I get thoughts on isolating the issue to the N75 or vacuum line from the N75 -> actuator ? Or are other components of the vacuum system also suspicious?
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
I agree with the last 2 posts.

There is a VW bulletin about the rusting.

I've read you can work the arm on the turbo manually back & forth to break up internal buildup. It may take 5 (or more) minutes.

When you re-install the actuator tie a piece of thread or floss to the E-clip.
It will be easier to find it if it flies off. I lost a few installing mine.
 

Owain@malonetuning

Associate Vendor , w/Business number
Joined
Jul 1, 2016
Location
Vancouver
TDI
PD jetta wagon
With rosstech you could log N75, boost request, and actual boost through any drive cycle under measuring block 11. That'll remove any guess work or potential damage, and after all time is money ;)
 

sassercollins

Active member
Joined
Aug 21, 2006
Location
here and there
TDI
2000 Beloved Golf, 4 Door, MK4 (AHL)
I did log the 002, 003 and 011 tests and uploaded them here.
Thanks for the log viewer MaloneTuning :)
I reached out to VCDS team but I don't understand what they say most the time. They did advise me to get an inline vacuum gauge to show me "what pressure is getting down to the turbo diaphragm. While watching the duty cycle in VCDS and the pressure
gauge when someone is driving, you should see a direct correlation/relationship between the two."

I think I'll just shoot the damn car.
 

KrashDH

Top Post Dawg
Joined
Dec 22, 2013
Location
Washington
TDI
2002 Golf
Here is the Vac system;

I've been actually troubleshooting mine as well because I lost my brakes (hard pedal) and turbo as well, so mine is a system issue rather than an isolated issue. Believe me, troubleshooting these systems is tedious, my car has been down for a week now.


Your N75 (#6) is controlling your turbo actuator (not shown). this is the first thing I'd check, I would make sure that the N75 holds vacuum and doesn't leak down. There's a couple tests you can do, if you have access to a mighty-vac just pull a vac on the N75 and make sure it doesn't leak. It can be a very slow leak.

Here is another check you can do that isolates the N75 and turbo from the rest of the system, outlined in this post:

http://forums.tdiclub.com/showpost.php?p=3737054&postcount=2:

You're very close.
First this to do is to isolate the turbo and the N-75.
Use a short section of vacumm hose (8") and connect between the "Vac" port on the N-75 and the vacumm nipple on the main checkvalve. (the one going from the brake booster to the pump)
This will eliminate every thing else in the vacumm system.
If you get boost your N-75 is operational.

If you want to verifi your N-75 you can remove your N-18 (EGR solenoid) and connect it to your turbo.
Just a word of caution:
Use some sort of means to mark / ID each of your vacumm lines so you prevent getting things crossed up.

To help make things a little easier you can remove the two 10 MM nuts that secure the solenoid "bracket". This lets you access all of the hoses with much more access than leaving both solenoids bolted in place.
Have you swapped your N18 (#4) and N75 (#6) valves to see if that solves your issue? Physically the same function they provide, just on different components.
 
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Owain@malonetuning

Associate Vendor , w/Business number
Joined
Jul 1, 2016
Location
Vancouver
TDI
PD jetta wagon
It's best to just log block 11 on it's own, because on the older ECUs the frame rate for logging is fairly low. A lot can happen to a turbo in a second, but I'd recon to guess something is wrong here :p


 
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JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
I once found an animated video for a VNT turbo. I forgot what exact words I used.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
I did log the 002, 003 and 011 tests and uploaded them

I reached out to VCDS team but I don't understand what they say most the time.
They did advise me to get an inline vacuum gauge to show me "what pressure is getting down to the turbo diaphragm.
Not to be nit-picky it's vacuum, not pressure that goes from the N75 to the actuator.

You need a few feet of vacuum hose and a plastic 'tee' for this. The tee has 3 ports.

You take the middle hose off the N75 (it goes to the actuator.
Cut a few inches of the new vacuum hose off, plug it into the fitting you just
took the hose off of.
Plug the new tee into the other end of the short hose.
Plug the line going to the actuator into another port on the tee.
Connect the rest of the new vacuum hose into the last port on the new tee and the other end to the vacuum gauge.

Do this with the car cold.
Start the car, you should get 10 inches of vacuum on the gauge.
With the Golf I don't know if you can see of reach the arm on the turbo that the actuator moves.
It should move when you start it.

Run the gauge into the car through the back of the hood and through the window.
Go for a quick ride. As soon as you start to go the gauge should drop lower.

Report back with the results.

Looking at the 2nd graph it looks like your not getting boost. :(
 

sassercollins

Active member
Joined
Aug 21, 2006
Location
here and there
TDI
2000 Beloved Golf, 4 Door, MK4 (AHL)
Actuator was at fault.

Thank you everyone for the suggestions and help. I am limited on a lot of the time and diagnostic tools required, BUT I did have an extra actuator that I slapped on and it is driving awesome. I took it down to the shop that told me to replace the turbo and got a refund on my diagnostic, and I am a happy driver again. I haven't taken it back up to that onramp location, but it drives great around town and feels like I have a tuned, upgraded diesel like I had paid for :)
 
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