AXR Motor: Rough running at low speeds during driving

Hello everyone,

Yesterday, I disassembled and repaired my windshield wiper linkage. To do this, I logically had to remove the entire fresh air intake system and the engine control unit (ECU) from the 9N with 1.9TDI AXR, due to space constraints.
Today, I noticed that the engine runs quite rough between 1200-1400 rpm when accelerating. I have already checked all the hoses and cables that were nearby. All error codes are clear. No perceptible performance loss, no idling issues, same problem with both cold and hot engine.
Unfortunately, I couldn't find a suitable article here in the forum. Does anyone perhaps have an idea of what I could check?

Thank you and best regards.
Maximilian

Hello,

- Are all the vacuum hoses connected?
- Did you forget to connect the crankcase ventilation to the intake manifold?
- Is the intake pipe correctly connected to the compressor?
- Intake pipe is bent, is it vibrating somewhere on it now?

Leaks in the intake air path are not only an acoustic problem; foreign objects (sand/dirt) sucked in can quickly damage the compressor and/or engine.

Hi, Rainer

Hello Rainer,

I thank you for your response. I have just checked everything again. Since I only removed things from the driver's side, because I only slightly shifted the front panel, I didn't touch the loading area.
Nevertheless, I have checked everything again, and it is all correct. I haven't found any cracks or anything like that either.
Maybe it will help if I can define this "roughness" a bit more precisely. I notice this "roughness" when accelerating at the above-mentioned RPM range. It feels like a very old diesel engine, and it's really "smooth".
That's not the case anymore. So, wie gesagt, ich bin etwas verwundert.
Do you perhaps have another idea?

Hi,
Maximilian

Since I also drive an AFN (in addition to the AXR),
I have extensive experience in this area.
"Collecting data on under load at 1400 RPM"
It was always due to vibrations in the area of Lufi to Turbo.
Experiment with using cable ties and foam supports.
for Lufi, and so on, to see if there is a positive effect.

Hello Klaus

Hello Klaus,

I checked all the hoses I had touched during the weekend and reconnected them. Afterwards, everything was normal again. I thought that was good . I don't understand it.
But I also checked for vibrations before. Still, thank you for the tip.

Best regards and thank you for your help
Maximilian