Turbocharger Failure: Lack of Power?

Hi everyone,

I'm really desperate. I wrote to you a few weeks ago that the engine in my Golf 3, 81 kW, AFN, is failing. No other defects were found, so the timing belt failure at 80,000 km was the primary cause of the engine damage.
I've now had a replacement engine installed. The engine itself cost 2,500 euros, the small parts cost 300 euros, and the labor cost 640 euros!
The problem is that the performance issues I had before are present again with the new engine. Around 3000 RPM, I end up in limp mode in 3rd and 4th gear. This happens more frequently in hot weather or rain. After restarting the engine, it works again, sometimes only for a short time, sometimes for the rest of the day. The error memory shows something like 'pressure difference regulation error.' The variable turbo geometry (VTG) is working smoothly, the mass airflow sensor (MAF) has been replaced, and the EGR valve has been cleaned. My dealership is convinced that the turbocharger is defective. They say they have had similar problems with other TDI engines, and in those cases, the turbocharger was also defective.
My question is whether the turbocharger is really the problem. Especially considering the cost of the ATM (presumably a repair or part), I don't want to spend another 1000 euros on a turbocharger. However, I want to get the car running again, so I would be willing to do so if everything is finally working properly afterwards.

Please help me, and I promise you this will be the last diesel I buy from VW!!!

Thank you very much, and best regards.

Henning.

Hi,
You probably don't have your own diagnostic capabilities, which is why you're getting this unclear error message.
Here are several options you have:

-You should take your car to a workshop that is equipped to handle the diagnosis and can log and analyze the data from the EDC (Electronic Diesel Control) during a test drive.

-You just collect the data and post it here.

- During a test drive, you should measure the voltage at the LDR yourself using an analog multimeter, and the charging pressure using some kind of pressure gauge.

If you have only moved the VTG manually, you should either apply voltage to the LDR with the engine running or disconnect the connector and see if the VTG reacts to it.

First, check if your vacuum lines are in good condition, and also inspect the entire charge air system for leaks! Check the EPW (magnetic valve for charge air control). Replacing the MAF sensor was pointless!!!!

Best, Ben.

Fidel wrote:

The error memory displays "vacuum regulation difference" or something similar.

Hi Henning,
You clearly belong to the group that should have read the LDA article earlier (click on my signature -> the essentials). Or better yet, read it now rather than later...

Otherwise:
I am unable to access external websites or specific files online, including the URL you provided. Therefore, I cannot translate the text from the German link.

Good luck!

Hi,

All the hoses are leak-proof and have been replaced as part of the engine conversion. However, the problem occurs more frequently (almost always) since the new engine was installed than it did before.
So, you're suggesting I disable the turbocharger, even though my car is jerky and barely produces any power at low RPM. The power loss usually occurs around 2800 to 3000 RPM; after that, a car with 45 horsepower has more power than my lemon. An LDA (Lambda sensor) isn't necessary because the problem already occurs regularly. What's much more important is finding a workshop that actually knows what they're doing!!!
The VTG (Variable Turbine Geometry) was only manually adjusted during the engine rebuild; I'm not sure if it functions automatically. If I were to replace the LDR (Lambda Dynamic Sensor) or the EPW (Exhaust Pressure Wave sensor), I'd probably end up replacing everything. I should really do some test drives with a computer diagnostic tool, but unfortunately, I don't have one.

Quote:

The error memory displays "vacuum regulation difference" or something similar

.

You never really know for sure... If it was a 'intake manifold pressure control differential', then the boost pressure is generally too high.
Possible sources of error:
- VTG - Adjustment difficult when hot.
- Vacuum cylinder for VTG (German railway company) - Malfunction in adjustment.
- Faulty solenoid valve for turbocharger pressure regulation.

Possible, but unlikely, sources of error:
- The boost pressure sensor is measuring waste.

As long as the turbocharger doesn't require oil and the variable geometry turbine (VGT) vanes aren't mechanically damaged, I wouldn't bother replacing it.

Best regards, Rainer.

The error code indicates 'vacuum pressure difference' or something similar .

You never really know for sure... If it was a 'intake manifold pressure regulation difference', then the boost pressure is generally too high.



The error code 'boost pressure control, deviation from regulation' can indicate either 'below' or 'above' the specified value. This needs to be determined first. If the deviation is negative (below), the actual boost pressure is not reaching the target value, which is usually due to a leak on either the high-pressure or low-pressure side.
If the deviation from the set rule is positive (i.e., the value is exceeded), the turbocharger anti-lag (ATL) system will, over a period longer than 10 seconds, generate excessive boost pressure (approximately 200-300 mbar too much). The cause of this could be a kinked vacuum line, a faulty electronic wastegate (EPW) (also check the EPW's venting!!!), or a stuck adjustment of the ATL system.

Okay,

Today, I looked into the VTG (Vertical Travel Gauge). I read something in this forum about being able to move the rod by 1 cm. I could only push it in a maximum of 5 mm. I created a vacuum in the hose using a syringe (and also by mouth). The rod moves. When I moved it manually, I was surprised by how difficult it was.
Is it normal for it to be relatively difficult with a working distance of only 5 mm, or could this be a reason for the poor performance?
I then replaced the hose from the turbocharger pressure control valve to the vacuum reservoir and took it for a test drive. For the first 5 kilometers, it drove like a car with 60 horsepower, and I had two instances where it went into limp mode. Then, once it was warm, it ran smoothly and responsively.
I have no idea what else to do. If I knew a good workshop, I would have already gone there. I'm not going to replace the turbocharger just yet.
I'd like to inquire about the prices for the wastegate valve and the VTG (variable turbine geometry) module today.
However, the spare parts expert had no idea.
Does anyone know the VW part numbers for the larger container, the heat shield, and the valve?

Best regards,

Henning.

'In my opinion, you can't buy the U-Dose separately, because adjusting the mounting would also change the charging rate. No reputable ATL manufacturer would allow that.'

It's normal that you might have difficulty pressing it manually, as you're pushing against a spring that is quite stiff. If your U-shaped vacuum gauge were defective, you wouldn't be able to move the rod at all. At approximately 600 mbar of vacuum, your gauge is at its limit. Now you can calculate the force required based on the area of the membrane in the U-shaped gauge! I doubt you can apply that force with your bare thumb. However, you can try pressing the lever down with a large screwdriver; it will be much easier that way.

You should perform an actuator test. This will allow you to see if the adjustment mechanism is working. However, this typically requires a VAG tester or other software tools that simulate a tester.

Ben1972 wrote:

In my opinion, you won't be able to get the U-Dose individually, because adjusting the loader during installation would change its settings. No ATL manufacturer would allow that. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. You should perform an actuator diagnosis;

this will allow you to see if the adjustment is working.

Quote:

However, this can only be done with a VAG tester or with other software-based tools that simulate a tester.

Hi Ben,

Here are my experiences again:
/viewtopic.php?t=3004
I even got a "dummy" casing from Schlütter for my VNT 15...

@Henning:
I have no idea what else I should do .
Are }all }the tips in the link too complicated for you, or do you also (sometimes?) only pay attention to what you are directly told?

Hi,
I have intentionally kept it brief.
You can find all the details, especially regarding the movement of the VTG (e.g., using indicator lights), in the specialized articles and older posts.

Okay,

I was able to move the rod with my bare thumb, but now I have blisters on my thumb because of it!
Regarding Ulf: I appreciate any advice you can offer, but my options are quite limited, so I'm starting by looking for the simplest solutions for self-diagnosis. I've printed out the rest and will show it to my mechanic. Since my action yesterday, it's running again. I don't have much hope that it will last, but you've at least saved me from buying a turbocharger and the potentially arbitrary decisions of my mechanic. Now, I'll be looking for a mechanic who has the appropriate experience and equipment to find the underlying problem.

Thank you very much.

Henning.