VTG adjustment or cleaning of the loader?

Hello,

I, too, am experiencing a problem with the VTG (Variable Turbine Geometry) adjustment, which means the turbocharger needs to be replaced or refurbished.

The adjustment of the rudder is so stiff that even the 'large motor' (which is already installed by default) doesn't provide enough power to move it. I read the technical articles and then proceeded accordingly.

I removed the vacuum cylinder used for adjusting the VTG (Variable Turbine Geometry), and tested its function using a large disposable syringe; the travel distance is okay (approximately 1.5 cm).
The VTG (Variable Turbine Geometry) was adjusted multiple times (more than 100 times) across its entire range while the engine was running; unfortunately, without success. The adjustment mechanism is still so stiff that the vacuum actuator cannot move it.

I assume that the guide vane adjustment mechanism is heavily coated with soot (or 'dirt') because I can adjust it manually. Basically, the mechanism seems to be working, but it's very difficult.

Has anyone in the forum ever disassembled a turbocharger and cleaned and restored the functionality of the nozzle vane adjustment mechanism? Or is disassembling and reassembling utterly hopeless?

Somewhere while browsing diesel mechanic forums, I came across an external (English) link where someone described the disassembly and reassembly process using pictures. Unfortunately, I didn't quite understand the conclusion. Besides worrying about his dirty fingers , did he successfully reinstall the loader?

While 'tinkering' with it, I noticed something that seemed strange: The vacuum sensor for the EGR valve has at least two small holes, about 3 mm in diameter, on its side, just below the ridge. The surrounding components are heavily soiled with 'soot splatters.' Is this original? Or is it part of a tuning measure?

Okay: Audi A6 Avant 2.5 TDI, 110 kW, engine code: AKN, MTM chip tuning (power output: ???).

Regards,

C.

Hello,

I wouldn't disassemble the charger yet. First, it's important to ensure that the control of the variable geometry turbocharger (VGT) is working correctly. To check this, simply observe the VGT linkage immediately after the engine starts; it should be fully pulled towards the turbocharger. In addition to manually adjusting the VGT mechanism, I've had good results with driving at full throttle on the highway for a few kilometers. Repeat this process several times until the VGT is free again. 'The black soot deposits are not normal and indicate a severely clogged EGR valve.'

Hello,

The control of the vacuum cylinder functions exactly as it should, as long as it is not connected to the VTG adjustment system. Shortly after the engine starts, it 'wanders' into the container.

I don't think driving at full throttle will help much (I think), because if there was a problem, it shouldn't have 'stuck' in the first place. I regularly drive on a 3-lane highway, at a convenient time of day, and without a speed limit, about once every 1 to 2 weeks. And I usually (when possible - which is almost always the case) keep my foot on the accelerator for about 20 km. Before that, I had already driven about 30 kilometers on a country road, so the engine was already at its operating temperature.

I have to do this tour again tomorrow morning. I'll definitely test it out again. It would be much easier than taking the loader apart .
I'm afraid it probably won't make a difference. Is there some kind of 'solution' that you can put the charger in that will dissolve the soot and whatever else has built up? But it probably won't be that simple, will it?

Regards,

C.

Good morning.

I'm not aware of any miracle solutions for releasing stuck VTG couplings; if there were, it would be too good to be true. Just try using the accelerator pedal (BAB) in combination with manually adjusting the coupling. When using the accelerator, try to accelerate and release the gas pedal frequently. While it's not exactly the best thing for the engine, it ensures that the variable geometry turbocharger (VGT) adjustment is constantly activated.

There are products called "tar removers" specifically for cleaning smoking chambers. However, these products tend to react quickly with aluminum. But they work great with other materials. I can't say how the Turbo will like it...

As long as you don't unscrew the running gear, disassembling and cleaning it is a very complicated and messy process, but it might help you solve your problem!

Take a look at this:

http://www.technologie-entwicklung.de/Gasturbines/VNT15-Turbo/vnt15-turbo.html

Regards,

Manuel.

Hi Cyber,

Disassembling and reassembling it isn't a problem, but it's a huge mess. You can remove the casing with the VTG mechanism and verschandeln it with water, a brush, and soap. Make sure to dry everything thoroughly and reassemble it carefully. Be careful around the charging wheel, and make sure nothing falls into the oil supply or behind the charging wheel. Don't even think about removing the front wheel, that would be a disaster!

It took me about 2 hours. However, the refurbished charger never actually made it into the car; it's currently stored in the basement as a spare. I can't say whether it would have made a lasting difference, but manually adjusting the VTG on this loader has made it work smoothly again.

The real challenge is definitely the installation and removal. At least for the A4!

Take a look at the link mentioned above; you'll see your VTG (Vehicle Tax Group) information there.

Don't forget to post the picture of the derailed VTG (for the forum).

Here's the translation:

'Just to reiterate the question, as it wasn't clear from your post:'
Is the vacuum sufficient, or what? Has it been measured? If there's not enough pressure, perhaps because air is leaking somewhere or the pump is faulty, then you shouldn't be surprised.
Tip (from someone who once unnecessarily disassembled a loader): First, measure; then, disassemble the loader.

Good luck.

Hi Cyber,

The real challenge is definitely the installation and removal. At least for the A4!



Not on the V6 .

The turbocharger is positioned nicely in the 'V' of the engine, which makes installation and removal relatively straightforward.
However, there are still black griffons.

Recently, I disassembled a GT1749VA turbocharger to verschandeln the variable geometry turbine (VGT) mechanism, following the instructions mentioned above. Once you manage to remove the screws on the exhaust side, the job is almost done. To verschandeln it, I used a toothbrush and solvent, not soapy water. After cleaning the mechanism, it's also best not to lubricate it with oil or grease, as this can sometimes cause more harm than good.
All in all, it took about an hour.

Best regards, R. Mark.

Hello,

Thank you very much to everyone who has been so helpful.

Unfortunately, the highway trip didn't achieve the hoped-for results.

Today I went back to the dealership, as you call it. They said they'll let me know by tomorrow how they're going to handle it in terms of goodwill. Then I'll decide whether or not to go ahead with having it disassembled. However, I would still be intrigued to take that thing apart and then get it working again.

@garth.brooks:
I did not measure the vacuum in the hose system. However, the vacuum actuator, upon starting (as described in the technical report), appeared to correctly actuate the movement of the threaded rod (in my opinion). Furthermore, the VTG adjustment is very difficult. I had to really put some force into it to move the lever; there was no way to do it with just two fingers.

How can the vacuum in the system be measured? Is a special vacuum gauge required for this?

By the way: I removed the vacuum sensor along with the mounting bracket and disassembled the threaded rod at the joint. This requires removing a small locking washer, but I skipped adjusting the threaded rod. You'll never be able to get it back to the same length. However, you have to be extremely careful to make sure that the part (the fuse plate) doesn't fall into the engine compartment.

What I also wanted to say is: This is already my second turbocharger. The first one was replaced free of charge after almost 50,000 km (I only had to pay for the labor, about 200 EUR). Now, after another 50,000 km, the next one is worn out. Could the cause be related to the chip tuning? However, it was only tuned at 30,000 km. Unfortunately, I don't know how 'aggressive' the tuning was. According to the statement at the time, it was expected to produce 30 more horsepower.

Yesterday, I ordered a 'small' diagnostic system from the online diagnostic shop. I'm going to log the boost pressure. I would like to avoid having to replace the charger every 50,000 km.

Regards,

C.

Hi,

Excessive tuning can, in some cases, increase the risk of turbocharger failure.
The loader, due to the tuning which pushes it to its limits, runs hotter than it would without the modifications. Additionally, the engine produces more soot emissions.

@ Cyberwalker

For some V6 TDI engines, for example. AFB 150 hp
"For many vehicles affected by this issue, were there improved exhaust manifolds available? This is dependent on the vehicle identification number, as the internal components of the manifolds can loosen and cause material to detach from the seals."
These dirt particles then migrate into the loader and settle on the guide vanes.
Following the major overloads and, in some cases, complete failures of the charger.

This is not a recall.!!
These manifolds are installed when there's a defect in the turbocharger, so that the next one doesn't fail again after only 50,000 km.
Basically, you'll need two new exhaust manifolds, and possibly the pipes that connect to the collector as well.

Check with your local dealer to see if your vehicle is affected.
"In some cases, we might be able to offer a partial solution as a gesture of goodwill." Because it's about 5.5 hours of work, and it's quite demanding.

Have a good trip.

Marco wrote:

The loader, due to the tuning in this specific case, gets hotter than it would without the tuning...

. . . and as a result, depending on the increase in exhaust gas temperature, the delicate VTG (Variable Turbine Geometry) mechanism can warp and become permanently jammed.
Of course, it also works without adding any significant amount of soot – and probably quite quickly, even when driving aggressively.

Steffarn's "crumb-crumb" theory, however, sounds quite convincing to me.

... I disassembled my old turbocharger (out of curiosity). It's not really that difficult, but I had the turbocharger removed because of excessive play in the shaft and a slight oil leak. The variable turbine geometry (VTG) is working perfectly and is in good condition. I could potentially send you the turbocharger housing with the VTG adjustment and wastegate, which might allow you to avoid needing a new turbocharger. However, maybe cleaning your turbocharger will be enough. By the way, I'm still looking for information on the exact location of the boost pressure sensor for this specific vehicle with a 110 kW V6 TDI engine. Thank you, greetings from the Harz region...

I am still looking for a clue as to where the turbocharger pressure sensor is located on this specific vehicle with a 110 KW V6 TDI engine. Thank you. Greetings from the Harz region...

Hello,

When it comes to an A6, the sensor is located in the sandwich cooler assembly (directly on the radiator). I believe the part is located in the left lower dashboard of the A4.

Hello,

I'd like to revisit this topic because I'm still having trouble with my 2001 Passat 130HP AWX engine. Occasionally, about once every 10 trips, the car loses power completely at speeds slightly above 100 km/h, until the next engine start. The error code in the diagnostic memory is 17965, indicating that the boost pressure regulation has exceeded its limit. I've read a lot (although some of it contradicts itself) and tried various things, and I found a damaged vacuum hose (the engine cover had worn it through) that leads to the exhaust gas recirculation valve, and a hose that had come loose from a check valve. Unfortunately, that wasn't the problem. Okay, I've checked the function of the vacuum sensor by disconnecting and reconnecting the hose to the pressure sensor. This seems to be working correctly. Also, the N75 valve has been replaced. Unfortunately, I don't have the ability to read the data values in detail because I don't have the necessary cable or software. VW says that there are essentially only two possible causes. The N75 valve, or the turbocharger where the adjustment mechanism is stuck.
Okay, here's the translation:

"Now, my question: Is it possible to check the adjustment manually while it's installed (since you can only reach it with two fingers)? Or could the mass airflow sensor (MAF) be the culprit, causing it to sometimes work and sometimes not?"
Please don't start complaining that this topic has already been discussed so many times.

Thank you.