ESP Replacement: Lingering Shaking (B4, 1Z)

After the ESP was replaced, a slight jerking sensation, accompanied by a very rough/rumbling engine sound, remains in the range of 1300 RPM.
Dies war neben dem Ruckeln bis 1900 u/min bereits vor dem Pumpentausch vorhanden. Ich hatte gehofft, dass dies ebenfalls an der Pumpe liegen würde. Unfortunately not.
The engine hum is present, regardless of the load conditions.
The slight vibration is only noticeable in the lower load range.
The valve timing was checked after the pump was replaced and was found to be correct.
How can the LMM (likely referring to a mass airflow sensor) be tested, and could it be the cause of the stuttering/jerking? I still have the older version with the air mass sensor.
How about the boost pressure sensor? Isn't that the RPM at which the turbocharger slowly starts to build up some pressure? How can the sensor be tested?
Can the old LMM version be replaced with the new one without much effort? Does anyone perhaps have an old version lying around, or would someone be willing to provide it for testing purposes?

Alternative:
What other options are there for achieving smooth partial-load rocking, or who can assist with testing?

Thank you and best regards.
Hermann.

I just ran a few more tests.
NHG connector disconnected: --> Still running roughly, with slight jerking, but with reduced power. Error message displayed in the cockpit.
LMM plug disconnected: --> Still rough running, with slight jerking and pulsating engine power (2 seconds more power, 2 seconds less power), no error message displayed.
The turbocharger wastegate valve is also new.

I'll probably look for someone in the area who has the same car and then gradually replace the remaining parts.

'Nevertheless, I would be grateful for any tips.'
Now, the pump can definitely be ruled out .

Regards,
Hermann.

hello
I have the same car, but it's a 1994 model without a chip.
I've gotten rid of my stutter almost completely (about 90%).
Sure, here is the translation of the text from German to English:

'wie folgt' translates to 'as follows' or 'the following'.

Timing belt replaced and adjusted - it was overdue and stretched.
LMM replaced - first, the old one was cleaned with gasoline, which helped a little. Then, since a replacement LMM costs 84 euros from Audi, it was replaced.

'Flange sealed at the intake manifold bend.'
'The intake manifold was cleaned - without being completely disassembled - only as far as possible after removing the upper bend. It had a build-up of oil carbon up to 8 mm thick. Afterwards, the EGR valve was closed off with a metal plate.'

'Air hoses, 5 mm in diameter, were shortened at the pressure switches, and the connection points were leaking.'
Replaced the needle lifter with a used one.
Fuel injection valves disassembled and drilled holes (0.2mm) inspected and cleaned.

Each individual adjustment influenced, reduced, or altered the shaking/vibration.

Initially, the car was almost undrivable at engine speeds of 1500-2000 RPM.
Now it's only 'noticeable' occasionally - only when easing off the gas pedal slightly in 4th or 5th gear - and it's not really bothersome anymore.

Yes, and also, I was able to reduce the fuel consumption by about a liter.

I also plan to check the accelerator pedal and the potentiometer in the ESP system.
best regards, georg

Hi Georg.

First of all, thank you for the tips.
Regarding this, I can say the following:
'I still have the older LMM model with the status disc; you already have the newer model. However, next weekend I have the opportunity to test a similar (older version).'
2. I have already fitted an original gasket to the flange on the intake manifold.
3. The intake manifold has been cleaned.
4. AGR is discontinued (due to bronchitis ).
5. Air hoses are leak-proof.
6. I'm getting a used NHG next week to test (I suspect there's a defect with mine).
7. I definitely will NOT be connecting the ESP to the potentiometer; the pump is only a week old.

Let's wait and see next week.
I reinstalled the original chip again to narrow down the possibilities. It's working better now. However, there's still a slight jerkiness at a constant speed of 1200 RPM in the 4th or 5th gear. If I accelerate, everything is fine.

It's possible that the engine control unit (ECU) is also the problem. However, I can test it, just like the mass airflow sensor (MAF), next weekend.

Regards,
Hermann.

There's a suitable mass airflow sensor available at the well-known auction house: 2471722884.
It might go for a very cheap price, because these things rarely break.

I have once again implanted the original chip, just to narrow down the possibilities.

@palmstrollo

I would be very grateful if you could tell me how to do it, as I have never done anything like this before. What should I be careful of, or is it simply a matter of flipping them over? As far as I know, the previous owner soldered two sockets onto the board, so you only need to flip the chips over, but can they be swapped or inserted the wrong way around? Thank you very much in advance!

Best regards, Torsten.

@ Torsten.

I sent you a private message because that doesn't belong in this thread.

Regards,
Hermann.