Lupo 1.7 SDI: Jerky, Low Power - Troubleshooting

Hello and good morning.

My sister's Lupo (model 6X, 44 kW, manufactured in 2000, naturally aspirated diesel engine, without a mass airflow sensor) has been experiencing problems recently.
Unfortunately, no error codes are stored in the system's memory. The car had already been checked for this issue two days ago.
at the VW dealership, where no fault could be detected (showroom effect).
A major inspection (including timing belt replacement) was recently performed.
The error had occurred sporadically before, but recently it has been happening more and more frequently.

Symptom:
Unexpectedly, the engine starts to sputter, and the vehicle then reaches a certain speed.
from a maximum of 80 km/h. Shortly after, he recovers and everything goes back to normal.

Does anyone have any advice?

Regards,
gobedi

How many kilometers has it been driven? Is there air in the diesel lines? Any leaks? Is the diesel filter sealed properly?
Is he smoking while doing that? Is the AGR (Exhaust Gas Recirculation) system functional, leak-free, and clean? That's all an SDI engine really has.

For the records, it should be an AKU.

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It has now been driven approximately 92,000 kilometers.
There are no visible leaks, and it's not producing any smoke.
We also suspect that the AGR (Advanced Gas-cooled Reactor) is the problem, and we will probably have to take it offline.

The error occurs more frequently at high ambient temperatures, but less often on cooler days.
Sometimes, not at all.

Regards,
gobedi

Okay, everyone, please check all the points, especially for any leaks. Otherwise, we're just guessing here.

Thank you for the feedback.

Then we'll get into this vehicle, which we affectionately call the "Tuckelauto."
we need to examine it more closely.

Regards,
gobedi

Hello, I'm experiencing the same symptoms with my Skoda Fabia 1.9 SDI (ASY).
Do you know what the problem is? I've already replaced the diesel filter, and there's no error code.

hey

I currently have a 1.7 Lupo (AKU) with 228,000 kilometers on the odometer.
I'm having a similar problem, but it's a bit more severe.

The engine has absolutely no power and is producing a lot of black smoke. The error code reader shows no errors, but when I run the timing checker, it indicates that the injection timing is far too late. However, adjusting the fuel pump doesn't change this.

I've already tried a few things, like disconnecting the AGR valve, disconnecting the temperature sensors, and the "throttle valve"?

Unfortunately, there was no improvement; on the contrary, it got worse.
Currently, almost pure diesel exhaust is coming from the intake manifold; it's as if the engine isn't getting any air at all.

Does anyone have any ideas?

Let's keep it simple. Are the intake passages clear? Is the air filter okay?

It's been clarified; the cat was closed.