TDI 96kW: Top Speed 130 km/h

Hello!

My 96 kW TDI has been running since yesterday as if it only has 40 horsepower. It doesn't have the usual power, and when I floor it, it only goes about 130-140 km/h (consuming approximately 6.2 liters according to the MFA).
At VW, you suspected the mass airflow sensor, but it's not the problem. During a test drive with a measuring device to read out data blocks, it was observed that there is no pressure (around 1030 mbar, I believe, at full throttle and approximately 3000 RPM, which is what the device indicates). All the hoses are connected, and now they suspect the turbocharger.
What do you think all of this could be?

After already dealing with endless idling vibrations, I'm now wondering if there might be a connection, such that some part has never worked correctly and has now completely given up (9 months: 21,000 km). However, after calming down a bit, I'm once again astonished by the VW quality (I just read an interview with Dr. B. Pischetsrieder, quote: 'FOR ME, A CAR IS GOOD WHEN IT DOES EXACTLY WHAT I WANT IT TO DO, AND NOT WHAT THE CAR THINKS IS RIGHT' !!!! So. Reality: He doesn't even deem it necessary to respond to my writing about the idling vibrations on my new TDI (or to have someone else respond... ). Or he believes that a car should sometimes vibrate when idling.
Well, I really miss my 110 hp TDI engine (AHF; 180,000 km with absolutely no vibrations, with significantly lower fuel consumption, and without ever having to accept any loss of power, or even breaking down, or having the turbocharger or anything else fail after only 20,000 km...).

Greetings.

Thomas.

Hello,

It sounds like it's in emergency mode. Does the filament glow continuously?
Did they also read the error memory at VW?

Hello,

'No, the glow plug isn't lighting up; it only does so briefly when starting, as usual. Otherwise, the car is running normally. There was an error code stored in the system. From memory, it was something like: 'Boost pressure limit exceeded' or something similar. I should have written it down. The VW technician said that there's no pressure being generated, always around 1020 mbar, even at full throttle and higher RPMs...'

Regards,

Thomas.

Thomas TDI130 wrote:

There was an error in the error memory. From memory, it was something like: "Boost pressure limit exceeded" or something similar. I should have written it down. The VW person said that there was no pressure, always something around 1020 mbar, even at full throttle and higher RPMs...

Hi Thomas,

Then, it's likely that no more boost pressure will be generated.

In the simplest case, only a turbocharger hose has come loose; in the worst case, the turbocharger is broken. In any case, the loss of power without boost pressure is completely normal.

Hello everyone,

Could it be the charge pressure control valve (that's what VW claims, anyway). They want to replace it...

Regards,

Thomas.

Hello,

Before we start replacing parts randomly, let's perform a diagnostic test. The data for this test can be found in the error database.
This should help narrow down the error.

Hello Michael,

Perhaps this is a silly question, but don't you think that the VW executives already conducted a similar test drive?

Regards,

Thomas.

Hello,

Based on my experience, VW mechanics often know the least (unfortunately). As many posts in the forum show, their assumptions can sometimes be quite outlandish.
I would specifically request a measurement run with a log and a printout of the error memory.
Important: Always stay focused and make sure that the conditions of the measurement run (see error database) are strictly adhered to. By the way, this is a very common mistake in workshops.
Make sure the mechanics don't simply delete errors; always keep an eye on what they're doing.
With this data, we can definitely narrow down the source of the error.

Hello!

Replacing the boost pressure limiting valve didn't help. The error memory indicates:

1 error detected.

17964 P1556 035
Boost pressure control.
Limit exceeded.

Read measurement block 10.

406 mg/H 989 mbar 982 0.0%

What does that say to you?

After the VW technicians performed a 'guided troubleshooting' process using their VAS 5051 diagnostic tool, which only pointed to the aforementioned valve, and if that's okay, they suggest a faulty turbocharger. Now, they want to replace the turbocharger on Monday.

'Honestly, I don't really mind (because I'm definitely getting new chargers for free), since everything is covered by the warranty, but I'd really like to be properly mobile again as soon as possible, without having to constantly swap one part for another for days on end. Unfortunately, I don't have the equipment (or repair manuals) to troubleshoot the problem myself.'
Do you think there's a way to test the charger without immediately replacing it?

Regards,

Thomas.

Hi,

Sure, but only with a boost pressure gauge or diagnostic tool.
Secure the VTG (Variable Turbine Geometry) at the turbocharger using a wire loop (which is pulled to the maximum position during engine start, unless a vacuum hose has a leak ).
Carefully start driving, and gradually increase the gas pedal.
When the engine starts to load, a boost pressure of 1.3 bar should be reached relatively quickly. At the latest when the boost pressure reaches 1.5 bar, the gas should be removed .
Mechanical testing of the charger:
- Remove the intake manifold.
- Insert your finger and check that the loading shaft rotates easily; a small amount of radial play is normal.

Best regards, Rainer.

Hi.

It was definitely the charger (9 months, 23000 km !!!!! ). I think I figured it out through trial and error (well, the 5051 was also right (coincidence?!)).

Unfortunately, the vibrations are still present, but he's scheduled for a special treatment soon...

Regards,

Thomas.

What exactly was broken on the loader?

Hi,

Unfortunately, I don't know either; I would have been interested to find out.
The VW employee just said that externally, there was nothing visible, and that having some oil inside was normal.

Anyway, it seems like he has rediscovered his form, and the problem seems to be gone.

Soon (when the weather is better, and I'm taking a longer highway drive), I'll check to see if there have been any changes to the top speed. Before, he sometimes had trouble reaching 220 km/h on the speedometer, while others with the 96 kW engine always claim to easily reach that speed.

Anyway, I will definitely report here what VW WOB or Bosch in Stuttgart says about the vibrating PDs (i.e., mine).

Regards,
Thomas.