Audi A4 TDI: Engine Misfire/Vibration at Idle

Hello friends!

I'm having the following problem!
My old Audi A4 2.0 TDI (BPW engine) is starting to show its age.
When the engine is at operating temperature, it starts to shake excessively when idling.
Minor glitches can also be observed during the warm-up phase.
During the load phase, vibrations also occur in the engine when it is at operating temperature.
I'm sure the problem lies in the area of PDEs.

I used VCDS to display the following values from measuring block 13, but I'm not 100% sure how to interpret these results.
One thing I'm sure of... Something isn't right .
The images should be viewed in reverse order.

I hope someone can help .

Has the PD cable harness already been replaced?

Not yet...
My suspicion is also in that direction.
I definitely want to replace the wiring harness on Saturday and install new gasket sets on all the PDEs.
Let's see if it helps.

Hi,

Please check the following:
/viewtopic.php?t=29489&highlight=bre+unsteady+operation

Best regards, Rainer.

Aua... It looks bad.
Well, I'll find out this weekend.
Thank you for that. I will report .

Okay, so last week I disassembled the injectors. Afterwards, I cleaned them in an ultrasonic bath at 70°C using the appropriate ultrasonic cleaning concentrate (Tickopur Tr 13) for about 10 minutes. I didn't notice anything visually unusual about the injectors. The pressure cones at the top of the nozzles were slightly worn compared to new ones, which isn't surprising after 350,000 km. The injector bodies had some carbon buildup... but that's also normal, I would say. There were some slight crescent-shaped scratches on the injector bodies caused by the one-sided mounting of the injectors in the cylinder head... but I've seen it worse even with less mileage.
The sealing rings were completely replaced, and the wiring harness was also renewed.
The wiring harness is really difficult to install and remove, because the engine is mounted longitudinally and the access opening is located on the side of the fender.

After the engine finally started after a long period of struggling, I immediately noticed a smoother and quieter engine operation compared to before.
"Meanwhile, I've been driving again for a week, and the engine is running perfectly in all operating conditions."

I can't say for sure what ultimately fixed the problem, but I think it's definitely a good idea to participate in all these activities if you're already there.

Until then .

Hi R0bÄrt!

First of all, thank you very much for your feedback!

Could you please provide us with logs or at least photos of the current values of the MWBs 13/18/23, so that future generations can also have something to compare the "before and after" with?
The PDEs were reportedly (?!?) correctly assembled and adjusted according to the manufacturer's instructions.

I think it was probably the aged and worn sealing rings, rather than the pressure pieces – although, according to the manufacturer's instructions, the pressure pieces should always be replaced when working on positive displacement elements.

Best regards from Passau!