TDI Power Loss: Troubleshooting & Solutions

Hello!

Ich war gestern auf einem Leistungsprüfstand mit meinem A3 96kw TDI PD. Leider hat sich wohl herrausgestellt, das mein A3 einen defekten LMM hat. Das Diagramm zeigt drei "Nasen" die nicht so toll sind. Direkte Aussage von Manthey .... LMM failure.
Okay, so I went to Audi today and had them read the LLM (air mass sensor). According to Audi, the LLM is fine. So, I called another tuner. I sent him the performance graph, and he said it's definitely an LLM issue. I replied that I had already been to Audi, and they said the LLM was okay. He then asked for the values of the measuring blocks and said that Audi had messed something up. Specifically, they should have read measuring block 10 at 100% throttle position, but it was only showing 24.5%. In measuring block 3, the target value is 850mg/H, while the actual value is 1014mg/H.

Which measurement block do I need to read to finally determine if the mass airflow sensor (MAF) is faulty? Or, what do you think about the "spikes" in the diagram?


Here is the performance chart: http://home.t-online.de/home/raoul.lehnertz/dia/l-diagramm.jpg


Regards,

Raoul.

Hello Raoul,

The target data can be found in the "Troubleshooting and Guides" section. This section also includes the relevant conditions and parameters. There are more than enough posts on the topics of performance loss and mass airflow sensor (MAF). Please take a quick look.

Hi Raoul,

As far as I know, VAG testers don't allow for continuous data logging (like VAGCOM), but only provide a snapshot. If the MAF sensor value happens to be within the acceptable range at the time of the test, then, from your perspective, the Audi people might be right...

Okay, first of all, thank you. I've found the target values.

Here are the readings I obtained from Block 10. This should be the correct block to determine if the mass flow meter is still functioning.

Reading measurement block 10.

298mg/H 999mbar 1275 24.7%

975mg/H 999mbar 2386 100.0%


Why are there two lines?? I can't make sense of it... What else could be the reason for the "noise"? Especially the one at around 2000 rpm is very noticeable!
I mean, if two mechanics say it will be the mass airflow sensor, I think they're saying that for a reason. *g*
I'll probably get some goodwill compensation, but Audi first needs to determine if the issue is actually a defect.


Raoul.