wiedermal probleme v6 TDI / nagelt, raucht, wenig Leistung | Posts 16+

Hello,

The values for the injection start time look good!
Due to the different noises, please check the values of the idle speed control.
Knocking can, of course, also be knocking... if you accelerate, the engine might slightly twist in the bearings, so it's not impossible that only a part of it hits somewhere, and it sounds like knocking due to the engine vibrations.

Best regards, Rainer.

Hello,

'The values look good, as Rainer already mentioned. I'll log the same values tomorrow and see what comes out. Regarding the vibrations and the excessive smoke (and only then, meaning a brief puff of smoke followed by zero power), have you tried disconnecting the AGR valve as a test? It's possible that the AGR valve is sticking intermittently. If the AGR is not already deactivated, a VAG-COM log of measurement group 3 at the time of the jerking would be helpful. If the MAF sensor is definitely new and working correctly, then, in my opinion, the MAF sensor values at the time of the jerking should be significantly below the target value because a portion of the fresh air is being incorrectly replaced by exhaust gases, or the charge air is being partially bypassed through the AGR due to its higher pressure.' The result would be stuttering and a lot of smoke under load. At some point, the engine control unit (ECU) likely adjusted the fuel injection amount to compensate for the reduced mass airflow (MAF) value, resulting in a loss of power and excessive smoke until the EGR system recovered. (This is just a theory, please correct me if I'm wrong).

After skiing on Sunday evening, I tried tinkering with it again, but nothing works!
I had already disabled the AGR (Abgasrückführung) last week, using a 1.5 mm aluminum sheet.
However, nothing has changed, neither in terms of the drilling nor the vibrations.
I don't know what to do anymore... *sigh*
'Also, der Motor läuft auch im Leerlauf rauer als vergleichbare V6 TDI engines... I'm already really starting to worry. Every time a B5 2.5 TDI drives past me, I listen carefully, and they all seem quieter than mine, or they don't have that knocking sound.'

Greetings from the Allgäu region.

Markus.

Hi,

Here's an excerpt from the private message sent to Merlin, for the forum:
Did you read the idle speed control values as recommended?
Significant variations in the performance of individual cylinders can be an indication of faulty fuel injectors (clarification can be achieved through subsequent compression tests and injector leak-off tests).
What often causes a knocking or rattling sound: slightly leaky exhaust manifold gaskets on the cylinder head or cracks in the exhaust manifold.

Best regards, Rainer.

Thank you for the clarification. I wouldn't have thought it had two. Is one for the left side and the other for the right side?

Greetings, WarLord.

Hi Warlord,

AFB/AKN engines have a timing belt specifically for the ESP (electronic stability program) and another one for the camshaft drive.

Hi Rainer,
Please don't hit me right away... because of. Values for the idle speed control... which measurement block do I need to access to get those?
Thank you very much.

merlin