Audi A4 2.0 TDI, BPW Turbocharger Boost Pressure Limit Exceeded

Hello!
I've recently experienced a massive fuel pressure problem with my Audi.
I hope someone here can help me.

Recently, the STG has been constantly switching the engine into the emergency mode during the final phase. Also, without the emergency mode, there is a lack of torque throughout the entire speed range.
The fault memory has recorded the following: "Boost pressure regulation limit exceeded."

Today, I started checking the underpressure system for the boost pressure regulation, suspecting a problem.

1.) VTG vacuum chamber with vacuum pump checked.
= No pressure drop - ok.
2.) VTG Cable movement checked
= The cable pulls and then returns to its original position in a uniform manner.
3.) Vacuum measured on the vacuum pump while the motor is running
= Measurement 900mbar - seems to be normal
4.) Diagnostic Test VCDS
= N75 is proceeding. The pressure drop at 95% PWM is approximately 800 mbar.
5.) The entire underpressure section is checked for leaks.
= seals.
6.) Loading area visual inspection for external damage to the extent of
available for viewing
= seems to be okay.

I conducted a LOG drive with the following results:

I have re-uploaded the LOG file in PDF format.
If the CSV file is not displayed correctly.
I am still in the job search phase

What does the turbocharger's housing look like?
Exhaust system clear? To test, you can remove the front tube and drive about 50 meters.
Suction system free of foreign objects, hose sealed?

Ok, so the carrot builds up a maximum of 100 mbar of pressure in the log.

Unfortunately, the logic is not optimal. However, please take a look at the technical article on creating the logic. There is a specific request for a Log with a speed range of 1.500-4.000 rpm, with 100% throttle, and using gear positions 3, 8, and 11.
With you, there is only a short section with 100% throttle (125-132 seconds). The amount of fuel injected and the air mass are not visible. So ists ein wenig Glaskugeln.

However, in the full throttle stage, the TL control seems strange to me: Initially, the values are still around ~80%, but the last four measurements with 100% throttle at 131-132 seconds suddenly show only 9% TL control. However, the initial emergency shutdown after 6 seconds could also be a more pronounced LD deviation.

Do you have the possibility to measure the boost pressure at the turbocharger during the test run? This is how we could catch a "turbo" (likely referring to someone involved in illegal activities related to turbochargers).

Greetings
Guste

Thank you very much for the answers.

So, wie gesagt. I am currently in the process of getting familiar with the VCDS and Dieselschrauber communities.

I will be putting a new LOG in again. However, it will be difficult to reach the 4000 rpm for the LOG, as the emergency shutdown program will be activated (9.9% PWM) at a maximum of 2500 rpm.
The hose appears to be sealed, and at idle, the pressure is 0.8 bar at the VTG.
Exhaust system is also free.
I will also take a look at the running shoes soon.
I also need to mention that the charger was recently replaced, approximately 6 months ago.
The battery is recharged. When driving with the new turbocharger, I've also noticed that it seems to come on quite late (around 3000 rpm), but once I repeatedly press the accelerator pedal above 2200 rpm, the turbocharger immediately spools up fully.
For the past two days, I haven't been able to achieve any load pressure.

Quote:

I also want to mention that the battery was recently replaced, approximately 6 months ago. The battery is recharged. While driving with the new turbocharger, I've also noticed that it seems to come on quite late (around 3000 rpm), but once I repeatedly press the accelerator pedal above 2200 rpm, the turbocharger immediately spools up fully.

This sounds like a defective turbocharger, or one that has been over-revved in an unprofessional manner. We have unfortunately discussed these issues here before. Unfortunately, some providers are unserious.

--> Expand and claim... or replace with an original part.

I have the same suspicion.
I just took another trip recently.
This time, a new problem... Particle Filter Warning Light.
Here are some data from the trip... I hope they were successful.


LG Robert

To achieve turbo speed, I stick to my own quote:

guste100 wrote:

Do you have the possibility to measure the boost pressure at the turbocharger during the drive, as a test?

This would ensure that the control signal remains intact and that the TL-press does not malfunction due to this (=TL malfunction).


Regarding the DPF: 83g at 60g max is a clear indication... How many miles has the BPW tractor actually run?

Greetings
Guste

Yes, I'm feeling sick... I see it exactly the same way.
The car has now reached 265,000 miles.
So, then it seems the matter is quite clear... new air filter and new particulate filter.

Do you know of any reputable suppliers for turbochargers and diesel particulate filters?
where you don't necessarily have to pay for audio prices?
Can you make a mistake when regenerating a filter?

Best regards, Robert

So, I would start slowly at first. verschandeln the DPF (If you do it yourself, there are instructions available, otherwise you can find professional companies on Google).
Not two things at the same time. There is a possibility that the TL is not actually defective; there is a chance.

At 83gr of ash, it is 80-90% full. Regeneration will then take place every 100 km.
Nevertheless, some additional pressure should still be built up.

If the DPF is a filter that uses an additive (Satacen)
Cleaning becomes difficult to impossible if the surface has been regenerated. (For example, in the case of the Passat 3B6). It only reaches around 350 degrees in normal operation.
Without sufficient pressure, regeneration will definitely not occur, therefore the warning light.

I would like to loosen the front pipe and then drive 50 meters with a pressure gauge.

No no, the particulate filter cleans itself without additives.
How do you mean by measuring the vacuum and driving 50m?
And how should I interpret the differential pressure in your log?
It is specified in a 3-digit mbar range. In my LOG, I only see readings from 40 to a maximum of 70 mbar?

LG

Quote:

And how should I interpret the differential pressure in the log?

Is without any meaningful data without the corresponding air mass flow rate (emergency mode).

Look:
/viewtopic.php?t=24222

In the log, it appears that no boost pressure is being built, i.e., I would first check whether the VTG (Variable Turbine Geometry) is actually being controlled by the turbocharger (check for vacuum), and perform a control element diagnosis in the engine control unit.

If the VTG control is functioning and the rest of the charger is also working, then you can focus on the likely severely clogged DPF.

Everything has already been checked... see above...

Hello,

I can hardly imagine that the DPF should suddenly be so severe. There shouldn't have been any oil leaks or anything else into the exhaust system, right?

Look, maybe something has come loose at the VTG, the adjustment lever isn't being held by the lever because there's no clip?

Quote:

The cable pulls and returns smoothly to its original position

Adjustable range? Approximately 1cm is expected.

Best regards, Rainer

I believe this is a result of the faulty charger, as the reconditioned charger did not deliver the desired performance even after installation. (Full boost pressure only achieved after repeatedly pressing the accelerator pedal from 2000rpm in 2nd or 3rd gear).

I will remove the air filter and the particulate filter on Saturday.
I will send the filter in for regeneration.

I will report back to you later.

Best regards, Robert