Unruhiger Leerlauf, 2.0 TDI, Pumpe-Düse, BRE | Posts 16+

Okay, I will try it out in the next few days and then let you know briefly how it goes.

Okay, so yesterday I disconnected the plug from the EGR valve. The engine immediately idles about 100 RPM faster. In my opinion, there's still some instability. After 1-2 minutes, the exhaust smell is noticeable again (possibly due to incomplete combustion, since the EGR rate is essentially zero). From a feeling perspective, I don't sense any improvement. I reconnected the EGR plug.
I then created a log file. I started the engine with a cold temperature and let it warm up to 50°C, measuring the temperature, target AGR value, actual AGR value, twist angle, actual air mass, actual boost pressure, and deviation for cylinders 1 through 4.
It is noticeable that cylinder 4 deviates significantly. It increases from 0.85 mg/H to 2.2 mg/H and then drops to 1.08 mg/H. After a gas injection (lines 507-509), the value for cylinder 4 rises again to 2, and cylinder 1 goes from negative values (-0.42) to positive values (0.87). I have no explanation for this.
I would like to add that I replaced the injector (cylinder 4) with a new one (not refurbished), because cylinder 4 in the engine always seemed to be the weakest.

Best regards, audifriend.

Hi,

I think you can rule out the AGR (Abgasrückführung) with that. Regarding the timing belt drive, is the belt tension okay, and are there any issues with the pulleys? Does it make any noises?
Does the timing belt run smoothly at idle and without any fluttering?

Best regards, Rainer.

Thank you for the quick response, Rainer.

I notice that you still suspect the timing belt drive. Therefore, I will take the time to examine it more closely again, and also check for any signs of "flutter." I will let you know what I find.

I just checked the timing belt drive. There are no noises and the belt is not fluttering. The indicator on the tensioner is 2mm to the left of the gap (in the marking position when stationary). However, when idling, it is exactly in the gap.

Hello everyone,
I was hoping someone would respond to my post and maybe have a tip for me. Or is this a lost cause? Did I do something wrong?

Best regards, audifriend.

Hi,

I'm slowly running out of ideas. Either there's something loose or intermittent issues with the rotating components, a software problem, or air bubbles in the fuel tank related to the diesel system. However, this is contradicted by the fact that the engine reaches its full power; if it were any of those things, it would be much more noticeable under heavy load and high fuel consumption.
AGR has already been ruled out.

It doesn't really make sense to re-flash the software or remove the transmission control module just based on a suspicion.

Is the load on the Lima (alternator) also not subject to significant fluctuations? Large fluctuations in electricity demand naturally also cause load fluctuations on the drive system. Perhaps it's worth checking the cable connections as well.

At this point in time, the best course of action would be to continue monitoring the situation and only resume the search when something changes.

Best regards,

Thank you for the feedback!
I feel the same way – I'm also out of ideas. I could go to the doctor, but I don't think they'll be able to help either.
I will follow your advice and simply continue to observe.

Best regards,