81kW TDI Drehmomentschwäche unter 2000U/min | Posts 16+

siliconsensing wrote:

I've been working on this issue with my 81kw G4 AHF for a while now and haven't found anything concrete. It has extreme acceleration problems up to 1900 rpm; after that, it runs as it should. The fuel consumption is 5.6 liters. VTG canister and hoses are in good condition. I'm starting to think I might not have enough compression, and that's why it feels weak at the bottom end. It has quite a few miles on it, over 320,000 km, and it's never had... What was traded (besides the mass airflow sensor and peanuts)? Ich hoffe ich komm irgendwann drauf.........

Have you ever driven a car without a license?

Hello,

Okay, the loader is back inside now.
I shortened the VTG rod by one millimeter. When in its relaxed position, the rod had too much play with the lever. I have now adjusted the rod to create a slight preload.
When idling, the linkage is pulled completely against its stop.

Subjectively, the torque now comes on earlier. In 4th gear, with the tuning applied, the strong increase in torque occurs at approximately 60 km/h.
Subjectively, it still takes 1-2 seconds for the turbo to kick in, but once it engages in third gear or higher, it's consistent because you don't notice it as much in the higher gears.

But my actual problem is still there.
In the first and second gears, it doesn't rev up as quickly as it should. Then, around 2200 RPM, it starts to jerk.
While it's not as pronounced now due to the temporarily deactivated automatic air recirculation system, it is still noticeable.

I briefly suspected the magnetic valve, but the VTG rod is being pulled all the way in at idle.

Was kann denn da noch in Frage kommen?

"Kat is still installed, but it broke during the winter, with dramatic consequences. The car's top speed didn't exceed 130 km/h, and it went into limp mode above 3500 RPM. The friendly... charged me €700 for that. I probably should have just installed a dummy pipe."

Andi.

Hello,

Today, I used a measuring device to check the vacuum pressure at the VTG valve.
The displayed value drops from 998 mbar (ambient pressure) to 510 mbar at the VTG sensor, resulting in a differential pressure of 488 mbar.

Is this within the normal range? Unfortunately, I couldn't find anything relevant when scanning the threads.

Greetings.

Andi.

Tip: Pay attention to the limitation related to air mass in the low torque range.

Best regards, Rainer.

Rainer K. wrote:

Tipp: beobachte mal die Begrenzung über die Luftmasse im schwachen Drehmomentbereich.

What do you mean? I could measure the boost pressure with my gauge, but right now I don't see a way to connect it. In principle, there should be some kind of small connector somewhere, right?
I don't have a VAG-Com device, so it will be difficult for me to do anything about the diagnosis.

Best regards, Andi.

Quote:

VAG-Com habe ich nicht, daher eher schwer für mich über die Diagnose was zu machen.

Then it won't just be difficult to determine a diagnosis, but getting any diagnosis at all will be very challenging...