Druckprüfung Ladedrucksystem | Posts 16+

klopfer wrote:

Column 3 (Is this the actual pressure?) shows a value of 1.030 mbar, which however drops to 989 mbar, thus creating a vacuum in the system. Is that even possible?

Sure, besides the air filter, there's also this "air measurement flap." It's equipped with a fairly stiff spring, so it will also create a corresponding pressure loss.

...or such trivial things as aftermarket air filters or modified intake paths...

Even a heavily loaded vehicle can act as an air brake when idling.

CU Gremlin.

@Gremlin

The air filter was replaced approximately 2,000 km ago as part of the 15,000 km service, which also included an oil change with new filters and draining of the diesel fuel filter. I didn't notice any altered intake paths during that process.

@diesel.gustav (in case you still want to respond)

Which statement from my first post in this thread are you referring to? I'm a little confused.

@donalexo

"The AGR valve has been stuck closed for about 12,000 kilometers. What if the high value reported by the mass airflow sensor (MAF) is incorrect? The engine control unit (ECU) would then release an injection amount based on this potentially too-high value, which could lead to smoke because too much fuel would be injected for the amount of air."

Best regards,

I'm also experiencing a strange noise when accelerating right now; let's see if it's the valve.
"In my car, the boost pressure rises to 1.1 bar and then drops back down to 0.5 bar. This happens about twice per second when I'm at full throttle in 5th gear, above 2500 RPM."

Oops, something seems to have gone wrong.

Hello everyone,
I need to bump this thread again because I'm experiencing the same issue, but there isn't a solution posted here yet.
'I'm seeing the same discrepancies in the load values at idle, and even at 3500 RPM, I still have a difference of 1700 target vs. 1350 actual (without any load; I don't have a laptop to read the data). I can't find any leaks. I checked this because the car is now consuming more than 9 liters of fuel (it used to be 7.5 liters), and you can no longer really feel the turbo boost. I can't check the maximum speed, as my winter tires only go up to 190 km/h, but it seems like it's still reaching that speed.'
The knob turns easily with your finger, and to avoid any losses in the EGR system, I initially put a piece of metal inside it.

@klopfer: Hast Du es hin gekriegt? What was it?

Regards,
Kai.

No, I haven't managed to do it yet. I was also on vacation for a while, and since I didn't have any other options, I had to carry out all my experiments outdoors, but the weather hasn't been suitable lately.

If I happen to find a solution, I will definitely post it.

Hello.
Thomas.

Hello Thomas,
So, you've been dealing with this issue since the beginning of December. What about your fuel consumption? For example, my maximum consumption in 6th gear has increased from 15.5 (full throttle, 225 km/h) to 17.5. Also, it reacts very sensitively to acceleration, but only on the MFA (Multi-Function Display), which doesn't translate into actual acceleration.

To all AEL drivers: What is your target value for boost pressure at idle?

Regards,
Kai.

Hello Kai,

Let's say I've known the child's name since early December, but I don't know how long the error has been there.

My fuel consumption is between 7.5 and 8 liters. Since I don't have an MFA (Multifunction Display), I can't give you any real-time data on fuel consumption. However, I only manage to reach just over 200 km/h very cautiously, but I also attribute that to my tires (235/45/17). My winter tires are only rated up to a maximum of 190 km/h; however, I have to admit that I don't want to push the engine too hard considering its mileage and the fact that I've only owned the car for 14 months and 20,000 kilometers.

If the weather permits, I'll go hunting again.

Regards,
Thomas.

I'm also experiencing a problem where my desired pressure is SIGNIFICANTLY higher than the actual pressure. Additionally, I've noticed that there's something happening in block...
"The last digit is almost always around 5.1%, except when under full load on the highway. Sometimes, the boost pressure is also close to..."
Boost pressure, even at low RPMs – in some cases, values exceeding 5.1% can be observed.
Since it sometimes reaches pressure, the issue shouldn't be with the charger, right? The EGR valve is still connected.
Here's an example of a test drive report:

Regards,
Ronny.

Could you please share the data logs from the dyno test (boost pressure, MAF sensor readings, etc.)?
They are then more informative than just a snapshot.

What is your make and model (MKB) and mileage?

Can VW check the turbocharger's boost pressure system for leaks, or at least test the intercooler?
Mine has a nice dent in it with some of the "chambers" bent out of shape.

Hello AndreasG,

Unfortunately, I can't perform the acceleration test because the automatic transmission is interfering .

I once tried to replicate the drag test in gear position D, but I only applied enough throttle so that the automatic transmission wouldn't downshift. I knew this wasn't an "Ulfscher Test" because I was also testing against air resistance.
Actually, I'm mainly concerned about the lower RPM ranges; I find the slow build-up of boost annoying – is that normal?

The MKB engine has AAT (air intake temperature) sensor. The turbocharger was replaced 30,000 km ago (with a new part), and the valve seats on the cylinder head were reworked (new stem seals were also installed). The turbocharger, along with the cylinder head and fuel injection pump, has a mileage of 280,000 km.

Best regards and thank you.
Ronny.

Here are the test results:

AndreasG wrote:

Please post the measurement data blocks from the dyno test (boost pressure, mass airflow sensor readings, etc.). They are then more informative than just a snapshot. What is your engine code and mileage?

ronny252 wrote:

I also have the problem that my set pressure is SIGNIFICANTLY higher than the actual pressure. Also, I noticed that in block... "The last digit is almost always around 5.1%, except when under full load on the highway. Sometimes, the boost pressure is also close to..." Boost pressure, even at low RPMs – in some cases, values exceeding 5.1% can be observed. Since it sometimes reaches pressure, the issue shouldn't be with the charger, right? The EGR valve is still connected. Here's an example of a test drive report: Regards, Ronny.

Hi, the 5.1% value in the last MWB11 reading indicates that the engine control unit is trying to maximize the boost pressure. However, it's not succeeding. How about you check everything related to the boost pressure regulation? Things like the solenoid valve, vacuum actuator, and hoses...

Today, I spent a long time troubleshooting a lack of boost pressure on an AEL engine. During the process, I noticed that the target boost at idle is 1250 mbar. I pressure-tested the entire turbocharging system and found no leaks. Voltage is present at the boost control valve. The duty cycle remains consistently at 5%. When I apply pressure to the hose leading to the boost pressure sensor, the wastegate actuator (LDR.AGR) also seems to function correctly. The turbine shaft also appears to be okay. I suspect a problem with the wastegate valve. I'll check it next week.