Welcher Zusammenhang besteht zw. Klimaanlage und Leistung ? | Posts 16+

Hi, I forgot to mention something. I'm hearing a howling noise around 2500 RPM in 2nd and 3rd gear. It appears about 3 seconds after I press the accelerator and it's a gradually increasing sound. This howling noise completely disappeared when I installed a nearly new mass airflow sensor (MAF) that a colleague gave me. But when I put the old MAF sensor back in, it suddenly started howling extremely loudly in 1st gear, which it never did before. What could it be?

cu moby

moby wrote:

In my opinion, the mass airflow sensor is not defective. See here: https://community.dieselschrauber.org/en/viewtopic.php?t=18274

Following the logic, I agree with you.

I don't understand why such significant differences occurred during the LMM switch. I also have no idea what's causing the howling.

moby wrote:

I'm hearing a howling sound around 2500 RPM in 2nd and 3rd gear. It appears about 3 seconds after I press the accelerator and is a gradually increasing sound. This howling was completely gone with the almost new mass airflow sensor (MAF) that I installed, which a colleague provided. When I reinstalled the old MAF, it suddenly started howling extremely in 1st gear, which it never did before. What could it be?

When I hear "strange howling," the EGR valve comes to mind, as it can produce some resonance noises in certain models: then, the diaphragm in the resonator vibrates in sync with the magnetic valve control, if I remember correctly.
Since the mass airflow sensor (MAF) is part of the EGR control system, the noise may change when the MAF is replaced.
Test: Disabling the AGR (Abgasrückführung) by disconnecting the valve and sealing the control hose.

I'm experiencing a howling sound around 2500 RPM in 2nd and 3rd gear. It appears about 3 seconds after I press the accelerator and is a gradually increasing tone. This howling completely disappeared when I installed a nearly new mass airflow sensor (MAF) that a colleague provided. When I reinstalled the old MAF, it suddenly started howling extremely loudly in 1st gear, which it never did before. What could it be?When I hear 'strange howling,' the EGR valve comes to mind, as it can produce certain resonance noises in some models: the diaphragm in the valve then vibrates in sync with the magnetic valve control, if I recall correctly.
Since the mass airflow sensor (MAF) is part of the EGR control system, the noise may change when the MAF is replaced.
Test: Disabling the AGR system by disconnecting the valve and sealing the control hose.

I've had issues with the AGR (Abgasrückführung) system before, and the AGR valve has already been replaced, as well as the pressure pipe leading to the AGR valve. The pressure pipe was loose, causing oil to leak out.

cu moby

Hallo, im Anhang seht Ihr das AGR-Ventil das innen an manchen Stellen abgeschliffen ist wie auch das Druckrohr zum AGR-Ventil hin dessen Verankerungen komplett abgeschliffen wurden. Welche Ursache könnte dies haben ? Too much pressure?

cu moby

moby wrote:

The AGR valve has already been replaced, as well as the pressure pipe leading to the AGR valve. This pipe was so loose that oil was leaking out. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. Hello, in the attachment, you will see the EGR valve, which has been worn down on some internal surfaces, as well as the pressure pipe leading to the EGR valve, where the mounting points have been completely worn away. What could be the cause of this?

No, it's simply the accumulated motor vibrations over the mileage.
These clip connections are almost always a bit loose and tend to leak oil. As long as the sealing ring at the front of the hose fitting is intact all around, and the two locking tabs haven't been worn down so much that the hose can slip out under pressure, then everything is "normal."

Here's a tip as a replacement for the worn-out "centering knobs": Wrap enough fabric or crepe tape around the degreased aluminum piece so that the hose fits snugly and securely in the AGR valve (making sure not to cover the locking tabs).

Near the air filter box, there's a buzzing sound at idle that's been present since I've owned the car... This buzzing only exists on my ASZ engine. If you press the lever on the EGR valve slightly downwards, the buzzing disappears. No buzzing can be detected at all on other comparable vehicles. Could the problem be located here? And if so, exactly where?If you're referring to the lever for the shut-off valve (which is operated by a small diaphragm and a flimsy plastic rod):
If the exhaust manifold (AK) closes partially during operation, it generally creates a lack of air, which can explain a loss of power, rough running, visible soot, etc.
A valve that is fluttering in the intake air stream can theoretically also produce humming noises, but it should normally be identifiable by an oscillating external lever - unless the connection between the valve and its rotating shaft, or the rotating shaft and the lever, is loose.

The membrane dosing holder can be adjusted by loosening the screws, allowing you to adjust the maximum spring force of the dosing unit towards the 'AK open' position. It's perfectly fine to experiment with this.
Of course, this also doesn't really help if the can, while driving, receives enough vacuum due to pneumatic malfunctions to turn the throttle valve away from the open position -> to be sure, additionally, as a test, disconnect the hose from the can (carefully, to avoid tearing off its nipple) and seal it.

Hello, I just tested the AGR valve in the basic settings mode (MWB 3). I can't hear anything... the air mass is always 490-500 mg/stroke... and when I turn off the engine, the lever makes a clicking sound with a delay of 2-3 seconds after the engine is turned off, moving upwards.
Is it even worth doing any of the things mentioned right now? By the way, the EGR valve is relatively new, and the problem started immediately after the replacement, but the workshop itself didn't know why. So, replacing the EGR valve didn't change anything at all. Is it possible to disable something like that in the engine control unit? They contacted Audi in Ingolstadt, and they said that there was something wrong with my engine control unit, that the values weren't correct... but I don't know exactly what. I looked at the adaptation channels and compared them to a similar car, but I didn't see any difference. Did they say anything else?

cu moby

moby wrote:

Hello, I just tested the AGR valve in the basic settings mode MWB 3. You don't hear ANYTHING... the air mass is always 490-500 mg/stroke... the AGR valve is relatively new, and the problem existed immediately after the replacement, but the workshop itself didn't know why that was the case. So, simply replacing the AGR valve didn't change anything at all. Is it possible to deactivate this in the engine control unit? They contacted Audi in Ingolstadt and said that everything was messed up in my engine control unit... the values weren't correct... but I don't know exactly what. I looked at the adaptation channels and compared them to a similar car... but I didn't see any difference. Did they say anything else?

Yes: probably chip tuning! To confirm, please log the MWB3 during a short drive with little gas, including about 10 seconds of idle in neutral.

ulf wrote:

The membrane disc holder can be adjusted by loosening the screws, allowing you to adjust the maximum spring force of the disc towards the "AK open" position: there is no harm in trying this. Of course, this also doesn't really help if the can, while driving, receives enough vacuum due to pneumatic malfunctions to turn the throttle valve away from the open position -> to be sure, additionally disconnect the hose from the can (carefully, to avoid tearing off its nipple) and seal it.

Quote:

When you turn off the engine, the lever makes a clicking sound and moves upwards with a delay of 2-3 seconds after the engine is turned off. Does it make any sense to carry out the above-mentioned things at this moment?

The lever must be pulled firmly towards the canister when the ignition is off, and it should automatically spring back when the engine is not running.

You should definitely try taking off the hose sometime.

Hello, I forgot to mention something important. The car started slowing down immediately after picking it up from the workshop. I was surprised at the time and thought it would resolve itself.

According to my repair history, the following parts were replaced:

Job titles:
Removed and installed one turbocharger.
2. Install/remove pumps/nozzles.

Part positions:
1 Gaiter (045115677A)
2 oil pipes (038145771AA)
3 Poetry (028145757)
4-piece gasket set (038198051C)
5 x Injector nozzle (038130079BX)
6 Turbol.agk (038253016FX)
7 Poetry (037253039D)
8 Poetry (3A0253115)
9 Sealing ring (N 0138123) (PD)
10 slices (N 90095501) (PD)
11 Mother (N 90200201)
12 screws (038103714A) (PD)

'Interestingly, I have the same entries again for the same day, but this time they are broken down in more detail regarding job positions. I've added '(PD)' in parentheses to make it clear what was exchanged in relation to the PDE.'

Can we infer from the replaced parts which of them might have caused problems from the beginning and led to this phenomenon? Also, what was removed during the turbo and PDE replacement, such as hoses, seals, control valves, etc., which may not even be directly related to the replacement itself?

At least with this, I can limit the time and the actions performed on the vehicle that led to this problem.

'At the time, the shaking problem couldn't be fixed with new PDEs... but temporarily, a new dual-mass flywheel (DMF) helped. After approximately 1.5 years and 15,000 kilometers driven after the DMF replacement, the shaking problem reappeared sporadically. After driving a total of 19,000 kilometers since the DMF replacement, I visited the workshop several times and complained about the shaking. However, they said it wasn't coming from the DMF and that a DMF wouldn't fail after only 19,000 kilometers. They wanted to replace the engine control unit (ECU), but I didn't want to, because the problem had been resolved with a DMF replacement before. So, it's probably not the ECU, right? On the other hand, my ECU is supposed to cause shaking during the warm-up phase due to the high EGR rate (according to ELSAWIN). However, the high EGR rate only appeared later, as I have a record from my seller (Audi workshop) showing that the intake air mass was 245 mg/stroke, which was fine. So, either the ECU is broken – there are some strange entries in the ECU after the PDE and turbo replacement, such as 'corporate data bus comfort, no communication, sporadic' or 'speed sensor right/left, mechanical defect, immobilizer diagnosis not possible,' which might indicate a problem – or something was done wrong during the replacement (e.g., a hose was swapped) or something broke... that's the question.'

I hope you can help me.

I'm going to meet someone later who has the exact same car, and I'm going to examine the vacuum hoses closely. I don't want them to have swapped a hose or drilled a small hole in one . What should the diameter of the hoses be if I decide to replace them? Can hoses from other MBKs be used?

cu moby

Hello, I met someone yesterday who owns the same car, and we compared them. The hoses seem to be fine, but we found several things that are concerning. Below, the transmission was visible because the round cover was missing. They probably forgot to put it back on a year ago when they were looking at the dual-mass flywheel. Furthermore, there was oil leaking from the hose located about 20 cm above the engine block, near the oil filler cap... this has been happening for a while... we always thought it was coming from the oil filler cap because there's also oil there... On the Y-connector that connects directly to the EGR valve and the turbocharger, there was oil residue. However, it wasn't the typical oily residue that attracts dirt... The solenoid valve was pressing on it because it wasn't in the correct position, and the hose wasn't fully inserted into the EGR valve... On the right side of the engine block, there's a hose that is completely full of oil, and it has even migrated upwards and formed a crust... this is about 20 cm from the hole near the transmission, which is open... However, the rod below it is not full of oil... No wonder my oil consumption is so high . I've always had very little consumption, and suddenly it's much higher.
Is the problem with the non-functional EGR valve located at the Y-connector?

cu moby

moby wrote:

Furthermore, there is oil leaking from the hose approximately 20 cm above the oil filler neck on the engine block... this has been happening for a while... we always thought it was coming from the oil filler neck because there is also oil there... At the Y-junction that connects directly to the AGR valve and the turbocharger pressure valve, there was oil residue. However, it wasn't the typical oily residue that attracts dirt... The solenoid valve was pressing on it because it wasn't in the correct position, and the hose at the AGR valve wasn't fully inserted... On the right side of the engine block, there is a hose that is completely full of oil, and it has even migrated upwards and formed a crust... This is about 20 cm from the hole near the transmission, which is open... 3 hoses and 1 hole, and there is no indication of which part is specifically meant: in this way,

I cannot help you.

Furthermore, there is oil leaking from the hose approximately 20 cm above the oil filler neck on the engine block... this has been happening for a while... we always thought it was coming from the oil filler neck because there is also oil there... At the Y-junction that connects directly to the AGR valve and the turbocharger pressure valve, there was oil residue. However, it wasn't the typical oily residue that attracts dirt... The solenoid valve was pressing on it because it wasn't in the correct position, and the hose at the AGR valve wasn't fully inserted... On the right side of the engine block, there is a hose that is completely full of oil, and it has even migrated upwards and formed a crust... This is about 20 cm from the hole near the transmission, which is open... 3 hoses and 1 hole, and there is no indication of which part is specifically meant: in this case, I can't help you.

Hello, sorry for being unclear... I meant the Y-shaped piece that's located between the EGR control valve and the boost pressure control valve, right underneath the solenoid valve. If it's still unclear, I'll take some pictures of everything tomorrow.

cu moby

moby wrote:

If it's still unclear, I'll take some pictures of everything tomorrow.

Yes, please do... and it would be best to write directly on the pictures which "intended" hose goes where - especially if it's not about obviously recognizable parts, like the thick air intake to the engine.

If it's still unclear, I'll take some photos of everything tomorrow. Yes, please do... and it would be best to write directly on the photos which 'intended' hose goes where - especially if it's not about obviously recognizable parts, like the thick air intake to the engine.

Hi, speaking of hose thickness... the control valves have 3 hoses connected to them... in my opinion, in both vehicles, 2 of the hoses were stiffer and one was softer. However, the softer hose on my colleague's car is connected differently than mine. Nothing has been done in that area on his car at the workshop yet. Could the cable have been swapped in my car? Or does the softer hose indicate a different average thickness of the cable?

cu moby

moby wrote:

There are 3 hoses connected to the control valves... in my opinion, in both vehicles, 2 of the hoses were harder and one was softer. However, the softer hose on my colleague's car is connected differently than mine. Nothing has been done in the workshop on that area of his car yet. Could the cable have been swapped in my car? Or does the softer hose indicate a different average thickness of the cable?

I have no idea, but the function of the system will certainly not be affected by a +/- 1mm internal dimension of the control hoses.
If you want to check your hose connections, refer to the pneumatic-FA .

Hello, I just tested the AGR valve in the basic settings mode MWB 3. You don't hear ANYTHING... the air mass is always 490-500 mg/stroke... the AGR valve is relatively new, and the problem existed immediately after the replacement, but the workshop itself didn't know why that was the case. So, simply replacing the AGR valve didn't change anything at all. Is it possible to deactivate this in the engine control unit? They contacted Audi in Ingolstadt and said that everything was messed up in my engine control unit... the values weren't correct... but I don't know exactly what. I looked at the adaptation channels and compared them to a similar car... but I didn't see any difference. Did they say anything else?Yes: probably chip tuning! To confirm, please log the MWB3 during a short drive with little gas, including about 10 seconds of idle in neutral.

The membrane disc holder can be adjusted by loosening the screws, allowing you to adjust the maximum spring force of the disc towards the 'AK open' position: there is no harm in trying this.
Of course, this also doesn't really help if the can, while driving, receives enough vacuum due to pneumatic malfunctions to turn the throttle valve away from the open position -> to be sure, additionally disconnect the hose from the can (carefully, to avoid tearing off its nipple) and seal it.
When you turn off the engine, the lever makes a clicking sound and moves upwards with a delay of 2-3 seconds after the engine is turned off.
Does it make any sense to carry out the above-mentioned things at this moment?
The lever must be pulled firmly towards the canister when the ignition is off, and it should automatically spring back when the engine is not running.

You can definitely try taking off the hose sometime.

Hello, I drove the car a few meters in the 30 km/h zone in second gear with very little gas. So, I was just cruising . I also logged the basic settings mode MWB 3.

Please refer to the appendix for values. For the leisurely stroll, please go to line 440.

I've noticed something strange. This problem has been 100% worse since last Saturday when we were working on the car and I turned the solenoid valve upside down (apparently, it's supposed to click if it's defective, but only the cap was rattling). By 'sorted,' I mean I only disconnected the hose leading to the air filter box so that the hoses could be arranged neatly.

The problem now is this: When you give it a little gas in second gear, and at around 2000 RPM, it completely cuts off the gas for a moment. But it also happened at higher RPMs, around 3000, but only in the first two gears. It's quite a funny experience *laughs*. Especially when you're slowly rolling in first gear and then suddenly press the gas pedal halfway, and the car develops so much power that only the wheels spin, and the ESP can't react quickly enough, and you feel like it's staying still with the spinning wheels. I immediately take my foot off the gas, but the car continues to accelerate for a little longer, as if the gas pedal was stuck for a moment. So, something is reacting with a delay, and the gas is completely cut off for a short time during acceleration. Did we break something during our work on it? Although I had this problem in a milder form before.