Allroad AKE V6 2,5TDI keine Leistung unter 2500 u/min | Posts 16+

@dieselschrauber:
Hi,
Okay, so the charger has been replaced... The behavior is identical with different chargers.

Regards,
Okay, please provide the German text you would like me to translate into English.

Hello everyone, is my assumption correct?
If I remove the catalytic converter from the loader, will that resolve the lack of power, assuming the problem is caused by a clogged exhaust? Or will there also be a problem due to the complete lack of water pressure?

Regards,
Okay, please provide the German text you would like me to translate into English.

altonno wrote:

Hello everyone, is my assumption correct? If I remove the catalytic converter from the loader, will that resolve the lack of power, assuming the problem is caused by a clogged exhaust? Or will there also be a problem due to the complete lack of water pressure? Regards, Al

.
No, in that case, the part should work and start producing gas earlier.

So, should the almost full power be available then?
I had tried it, and I couldn't really notice any difference.

Okay, so it seems like the troubleshooting should now focus more on the VEP (Visual Evoked Potential) tests?


Regards,
Okay, please provide the German text you would like me to translate into English.

dieselschrauber wrote:

Hello. It's possible that the VTG (variable turbine geometry) is not properly adjusted on the turbocharger. If the AGR (exhaust gas recirculation), MAF (mass airflow sensor), and vacuum system are all functioning correctly, this is something that should be checked. You can quickly see what the VTG's duty cycle is. Since I didn't find any significant issues in the log I was reviewing, please mark the length of the VTG adjustment rod (precisely! Use a color mark on the adjustment nut, and measure the rod length) and shorten it by one (1) revolution. Then, test drive. Best regards, Rainer

Hello Rainer, I have already read about the VTG adjustment and I have not ignored it .
The issue was that I had replaced the charger just last week with a "new" refurbished one. And the behavior hadn't improved. Therefore, I came to the conclusion that the problem wasn't the charger. "Of course, I could reinstall the old one and try adjusting it a bit."

Regards,
Okay, please provide the German text you would like me to translate into English.

If you don't want to look for the cause, then just keep trying different things...

Hi Rainer,
Sure, I want to find the root cause... that's what I'm aiming for. I'm also very grateful for any input you can provide. I just wanted to say that the charger has already been replaced, so the question is whether there's a high probability that something is actually wrong with the charger.

Okay, please don't misunderstand my responses.

I'm going to reinstall the old loader and then try out different settings.

Regards,
Okay, please provide the German text you would like me to translate into English.

The goal is to determine whether a more precise control of the VTG (Variable Track Geometry) system is sufficient to achieve good driving characteristics.

Then you know in which direction you need to continue searching, or whether you should just leave it as it is.

Okay, I'll try that now!

Hi,
"In addition, you can perform the test described in the second link above - /viewtopic.php?t=10810 - to check for misadjustment of the VTG (Variable Turbine Geometry). When there is suspicion of a misadjusted turbocharger, you can use VCDS in the basic settings mode of the engine control module (ECM) 11 (or the dropdown selection for newer engines) to quickly check whether the VTG is working and whether the setting for the closed position is correct. ..."
In my opinion, the problem clearly lies with the turbocharger, and it would be quite misguided to look for issues with the fuel injection pump or the mass airflow sensor.
hg
Herbert.

Hello and thank you again... I've read it through again and I think I understand everything so far. Unfortunately, I'll be away for a few days and won't be able to get to the car. I'll try it out sometime towards the end of next week.

Regards,
Okay, please provide the German text you would like me to translate into English.

Hello everyone,

I finally had some time again and was able to put the tips into practice.

I swapped the turbocharger back again. While doing that, I noticed that the pipe between the turbocharger outlet and the EGR valve was broken! I have no idea how I could have missed that last time. I even specifically looked at it. However, it's blocked again now.

I also shortened the connecting rod by exactly one rotation, as suggested. After assembly, the car is now "driveable," definitely much better. Now, of course, I don't know for sure whether it was primarily due to the leak being fixed, or to the adjustment of the tie rod.

Unfortunately, I didn't have a tester available to log the result. However, starting at 2000 RPM, there was a noticeable and significant increase in torque.

I then, as a test, shortened the tie rod by another full rotation, but nothing noticeably changed. Attached is the log from the version with the tie rod shortened by two rotations. You can now clearly see a significant overshoot.

I would now turn the rod back one more revolution and test it again.

What the logs now show (and what is also felt in reality) is that not much happens below 2000 RPM.

But, as I said, purely in terms of performance, the vehicle is now significantly more powerful and responsive.

Attached is a Screenshot of the log.

Shouldn't the boost pressure be significantly higher than 2000? Is that correct? Where else could I start?

Looking at the N75, it operates at under 2000 RPM at around 80%. Doesn't it open up to 100%? Then, according to my understanding, the AGR position would be somewhat more aggressive, wouldn't it?

Best regards, Al.

Hello,

Thank you for the feedback. But two bad things at once.

Quote:

I swapped the turbocharger back to the original one again.

Never requested. If you have a new one, then you just leave it in.

Quote:

I then, as a test, shortened the tie rod by another full rotation, but nothing noticeably changed.

I said *one* revolution, and I emphasized "one" because if the overspeed is too high, the turbine shaft can break from the compressor. Puff, broken, engine failure.

At least you checked how the wastegate looks; it's now as expected, too high. Also, I suspect the old (carbonized) turbocharger has been reinstalled, which seems to be causing the VTG (variable turbine geometry) to jam. The boost pressure drops almost abruptly from 2500 mbar to 2000 mbar. The target boost pressure is still not being reached at 2000 rpm.

Quote:

While doing that, I noticed that the pipe between the turbocharger inlet and the EGR valve was broken! I have no idea how I could have missed that last time.

Yes, I have no idea. Usually, you don't even need to see it, because you can already hear the loud hissing sound when you accelerate.

Best regards, Rainer.