Audi A3 TDI: Rough Running at 1900-2300 RPM

Hello,

I'm having this problem that no workshop (three different ones) has been able to fix.
When I accelerate from 1500 RPM to 1900 RPM in gears 2 through 6, the engine feels rough and underpowered. The power delivery isn't right. Even if I press the accelerator at 1800 RPM, the same thing happens... regardless of the gear! This rough behavior is especially noticeable when accelerating uphill. From approximately 2200-2400 RPM, the engine runs smoothly again and pulls strongly, although it's quite loud. The car also makes a humming noise, which can be heard even at 130 km/h in 6th gear when accelerating. Sometimes, I notice that the turbo doesn't engage when I accelerate, so I briefly release the accelerator and then press it again, and then the turbo kicks in. Furthermore, in the first two gears, the engine sounds like a vacuum cleaner during acceleration, and between 2500-3500 RPM, there are brief power interruptions and small jerks.
'I test drove the same engine in an A3 a week ago for comparison, but it had 500 km less mileage (mine has about 24,000 km). It ran smoothly through the same RPM range, and the engine felt much more refined. Also, there was absolutely no noticeable noise or vibration inside the cabin.'
Note: Replacing the LMM (mass airflow sensor) didn't solve the problem, and disconnecting the EGR valve also didn't fix it. It only resulted in reduced power and a noise when turning off the engine that sounded like the turbocharger was decompressing (which is no longer present after reconnecting the EGR valve).
I hope you can help me. I'm at my wit's end, or rather, I'm completely stuck with these workshops.

Sure, here is the translation of the text from German to English:

'CU Thomas' translates to 'See you, Thomas.'

moby wrote:

I hope you can help me. I'm at the end of my rope, or rather, with the workshops.

Well then, take matters into your own hands and put pressure on the EDC (most workshops will give up as soon as the mass airflow sensor and turbocharger are replaced).

A LDA (even if only temporarily) would already be a good start.

Otherwise:
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.
Okay, I'm ready. Please provide the German text you want me to translate into English.

Hello!
It seems like you're experiencing the same problem as I am! What's strange is that yours uses a pump-injector system, while mine still has a distributor injection pump (A3 110PS TDI). In my case, this humming starts around 2000 RPM and disappears again at approximately 2300 RPM. It also occurs in every gear (which at least rules out the transmission! ). For me too, it's particularly noticeable when driving uphill (especially in second gear). However, the performance isn't noticeably bad. Although my results are on the lower end during a power test, there's no immediate cause for concern. I have deactivated the AGR valve, the VTG is working without any issues, and the injection pump has been replaced and re-calibrated (although perhaps not correctly ).
Besides that, I couldn't find any errors, and I've also already posted here in this forum without success .
For me, fuel injectors are almost the only option left. My car now has over 152,000 kilometers on the odometer. However, these things are quite expensive, and it's hard to justify spending that much money just to see if the noise goes away...
Perhaps someone else is experiencing this or similar problems .

Hello,
Is my problem that rare? I assume it is, because if not, someone would have already solved it by now. This includes my mechanic's shop.
The boost pressure control valve was broken. After I installed a new valve (about 4 weeks ago), the fuel consumption increased from approximately 5.2 to 6 liters at 130 km/h. It ran great for 2 weeks, but now it's running poorly again for the past 2 weeks. When accelerating hard, there's occasional hesitation between 2500-3500 rpm, and it feels strange when reaching higher speeds. A light touch on the accelerator doesn't engage the turbo. And the fuel consumption has been around 7.8-8 liters for the last two tanks! According to the workshop, the mass airflow sensor is fine, but I have serious doubts about that. Besides that, my car still makes a loud rumbling noise and vibrates between 1900-2200 rpm as if it's about to stall, especially noticeable when going uphill, which I mentioned earlier.

a) I'm wondering why my car is making a buzzing noise.
b) I'm wondering why it ran perfectly for only 2 weeks.
c) I'm wondering why the fuel consumption is so high.
d) Are there any benchmark values for fuel consumption? (My current consumption is, for example, X liters per 100 km at 130 km/h in 6th gear, or Y liters per 100 km at 70 km/h in 4th gear.)

I hope you can help a desperate Audi A3 driver *please*.

Sure, here is the translation of the text from German to English:

'CU Thomas' translates to 'See you, Thomas.'

If you've ruled out any engine-related issues through testing (including using a tool like VAGCOM), then I would investigate the exhaust system as the source of the humming noise.

In a golf car, shifting the exhaust hanger on the front center muffler (where that strange bracket with two rubber pieces is located) by just 2-3 mm can create a noise inside the vehicle's cabin, as if the car has no sound insulation whatsoever.
Perhaps something shifted over time, became misaligned, the rubber parts slowly deteriorated, or something similar happened.

Since the A3 and the Golf have a lot in common, that might be a good starting point.

How do you mean that with a shift of 2-3 mm?
I'm also having the same problem – mine is much too loud, but I hadn't even thought about that.

Hello,
Okay, the engine mounts were replaced because there was a significant amount of play in the clutch system.
The exhaust was also checked. I had a power test done before the turbocharger pressure control valve was replaced. The results were: 149.6 horsepower and 342 Nm of torque. Is that normal with a faulty turbocharger pressure control valve? It seems strange to me. The car is not tuned. I specifically asked the seller if it was tuned, and he said no. By the way, my car has 33,000 kilometers on it *smiles*.

Sure, here is the translation of the text from German to English:

'CU Thomas' translates to 'See you, Thomas.'

moby wrote:

I had a power test done before the turbocharger boost control valve was replaced. The results were: 149.6 horsepower, and 342 Nm of torque. Is that normal with a faulty turbocharger boost control valve?

In this role, almost everything is normal...

Hey Moby, what kind of engine do you have?

Hello.
I have the ASZ engine in my Audi A3, manufactured in July 2002. It's the 131 hp common rail diesel engine. (Diesel, of course.)

33,333 km driven

Sure, here is the translation of the text from German to English:

'CU Thomas' translates to 'See you, Thomas.'

Hello,

What is that sound you hear about a minute after turning off the engine? It sounds like two creaking doors closing, with about a 10-second interval between them. And is it normal to feel a jolt when you turn off the automatic climate control while standing still? Does this happen until you turn it back on? Also, is it normal to hear a buzzing sound coming from the speakers for about 10 seconds after getting in the car without doing anything? When I remove the ignition key, there's also always a crackling sound from the speakers. This has been happening since the day the passenger-side airbag broke for an unknown reason.

I also have a fuel consumption of approximately 7.7 to 8.2 liters (not a Quattro or Tiptronic).

I hope you might have a solution... I've been to the workshop countless times and I'm starting to lose my patience.

Sure, here is the translation of the text from German to English:

'CU Thomas' translates to 'See you, Thomas.'

Where does this creaking sound that you mentioned come from?

Hello,
The noise is coming from the engine compartment. I haven't been able to pinpoint exactly where it's coming from within the engine bay yet, but I will try to figure it out.

Sure, here is the translation of the text from German to English:

'CU Thomas' translates to 'See you, Thomas.'

Hi!
I've already commented at the top because I'm experiencing similar symptoms in my A3. I initially ruled out the transmission as the cause. However, I'm starting to doubt that now. First, I thoroughly checked the engine using a diagnostic tool and couldn't find any abnormalities related to the rough running (turbo pressure, injection timing/amount, etc. --> OK).
However, I've noticed that I can largely prevent this humming sound by holding the gear stick firmly. Or, if I push the gear stick against its stop (e.g., in second gear), the humming is significantly reduced. While this doesn't fix the underlying cause, I suspect there might be a problem with the gearbox itself. Since it occurs in every gear and within the same RPM range, it likely originates from somewhere near the gearbox input.
I'm just not sure if it will eventually lead to a bigger problem. I've actually had that humming noise since I owned the car. Now, I've been driving about 65,000 km with the humming without anything getting worse. (Total mileage: 163,000 km)
Since I'm not an expert when it comes to transmissions, I'm hoping for some tips from the forum. Maybe there's a simpler solution than replacing the entire transmission...

Sure, here is the translation of the text from German to English:

"MFG" stands for "Mit freundlichen Grüßen," which translates to "Sincerely" or "Best regards" in English. It is a common way to end a formal letter or email.

Hello,
Regarding this, I've also noticed something on the transmission.
'When I press the clutch and engage first gear, I feel a vibration in the area around the transmission for a moment, and you can hear a brief humming sound inside the car. If I then shift back to neutral and re-engage first gear without releasing the clutch, it doesn't happen. However, if I release the clutch again and press it down, then engage first gear, the humming sound returns for a moment.'
The buzzing sound starts approximately halfway through the shifting process.


Sure, here is the translation of the text from German to English:

'CU Thomas' translates to 'See you, Thomas.'

Hello,
I drive a Golf GTI TDI, AFN with 110 horsepower; It's strange because I've also been experiencing the vibration problem for about 5-6 days. I've already been to 2 different workshops, but no luck . The vibration occurs at approximately 2000 RPM in all gears. Everything that is fixed vibrates: the steering wheel, seats, gear stick, all trim pieces, and the dashboard. I've also noticed that the engine has become louder. However, there hasn't been any loss of power yet, thankfully! Both mechanics suspected a problem with the front engine mounts. They are quite expensive, 160€ (because they are hydraulic!). But suspicion is not the same as certainty. Most likely, what I suspect is that the transmission is failing.
As I mentioned, about 5-6 days ago, I was driving home from work (about 2 miles) and, while turning right from the fourth lane (speed limit 60 km/h) into the third lane, I ran a red light.
(Reduced to 40 km/h) to pass the wave, and at that moment I heard a strange noise (2 seconds long), as if a can of soda was rolling under the car. Since then, this vibration in the car has been bothering me.
Is it the transmission or the engine mount? Who can answer this question for me and my colleagues?

Thank you in advance.

Regards,
wiarsix - High School.