Leistungsmangel / Rauchbegrenzung AVF | Posts 32+

Hello there!

Unfortunately, strengthening your turnips won't help in this case.
I've only owned the car for a year, and it has 30,000 kilometers on it now (current mileage is 230,000 km), and during that time, the turbocharger hasn't been replaced or repaired.
Was vorher war, kann ich leider nicht sagen und auch nicht nachfragen da ich den Wagen von Privat habe und die Nummer von dem Typen nicht mehr. Sorry!

Now, your signature is kicking in, unfortunately...


I once compared the performance data from "chli1976".
Then I placed a trend display on my N75 valve and noticed that the value is constantly increasing, which indicates an adjustment of the valve's control range. Does a high value mean that the impeller blades are more closed?


It's so stupid, but also, just problems with this thing...

Hello,

Quote:

I've only had the car for a year and 30,000 km.

Has the problem been present since you've owned the car, or did it develop gradually or suddenly?

Best regards, Rainer.

Hi.

The problem has only appeared for about 5000 km.
It didn't exist from the very beginning!

The logs from April also show that the car is capable of something different!

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

"Best regards," or "Sincerely,"

Hello, it's me again.

Am I already annoying you?


So, this morning I browsed through the data blocks.
While doing this, I noticed that the engine temperature is constantly at 36°!

However, my dashboard and the climate control system's diagnostic menu show readings of 88-92°C.
I always thought that the climate control system got its temperature reading from the engine control unit, but now I know better...

The error memory indicates that the sensor occasionally experiences a short circuit to ground.
If I press the accelerator now and move the engine, I will also get a higher temperature reading.
Okay, so: Cable break! (That's what I would say as a mechatronics engineer right now.)
Because the sensor shouldn't actually be defective, since if it were, it could also display higher values!

Okay, does anyone have an idea what resistance a temperature sensor would output at 90 degrees Celsius? I could temporarily put in a resistor to simulate that temperature for testing purposes.
I will address the problem (on Sunday) and check the cables and connectors. It's really difficult to access everything! Should I replace the sensor at the same time?

Does the engine limit performance if the temperature is not correct? Actually, it shouldn't, right?

Best regards,
Florian

Gilliearnie wrote:

The error memory also indicates that the sensor occasionally has a short circuit to ground. If I press the accelerator now and move the engine, I will also get a higher temperature reading. Okay, so: Cable break! (That's what I would say as a mechatronics engineer right now.) Because the sensor shouldn't actually be defective, since it could then also display higher values!

In the case of a cable break, the error message should more accurately indicate an "open circuit" rather than a "short circuit," IMO.
While the bearings are unfortunately known to be wear-prone parts, given your symptoms, I would also tend to suspect a cable problem.

Quote:

Does the engine limit power if the temperature is not correct? Actually, it shouldn't, right?

There are indeed temperature-dependent power limitations (high coolant temperature limits, boil-over protection, etc.).
But none of them, as far as I know, distort the LuMa/LD relationship in the way that is visible in your logs. And somewhere there lies the cause, in my opinion.

EDIT
What does the valve timing look like? Sometimes the camshaft lobes and the sliding surfaces of the hydraulic lifters wear out, and as a result, the affected valves barely open anymore -> this throttles the flow of air/fuel mixture. This would therefore also perfectly match your symptoms...

Hello,

Quote:

Because the sensor shouldn't actually be defective, since it could then also display higher values!

The coolant temperature sensor has two senders; one is used by the engine control unit (ECU), and the other is used by the instrument cluster. Which of the two is used for the air conditioning system would need to be checked. However, it wouldn't surprise me if the air conditioning system uses calculated values (e.g., engine running time) that have nothing to do with the actual measured values.

Best regards, Rainer.

Yes, I've also figured out that it's a dual-temperature sensor.

However, since the reading on the climate control display (I believe it's a value of 46) also fluctuates, specifically whenever the temperature valve opens and closes, the temperature varies between 88° and 92°. Therefore, you can clearly observe the opening and closing of the secondary cooling circuit.

Well, nevertheless, I logged the MWB 007 data (which includes coolant temperature and intake air temperature), and there was a brief spike in the coolant temperature to about 80°C for approximately 0.2 seconds.
Is 39.6° a standard value that the engine reads when the temperature sensor is not connected?
I will definitely look into the problem and try to figure out what's causing it.
Let's see what happens, but if Ulf already thinks that the cooling temperature probably doesn't have a big impact, I'm not entirely convinced myself!

Good morning to all the helpers.

I have found my power loss (at least theoretically)!

Yesterday evening, I did the following again:
- EGR system truly sealed with platelets.
- The throttle stop valve is fixed in the open position.
- Reinstalled the old LMM (Ladedruckmessmodul/boost pressure sensor).
- Removed the crankcase ventilation system, sealed the intake manifold, and placed a cloth over the end of the crankcase ventilation hose.

I suppose the power loss was caused by the bypass valve.
It was quite easy to move, and it's possible that the high flow rates caused the valve to close slightly.

I hope there isn't any problem in the area of the crankshaft housing.
That would be kind of silly!

The master mechanic in the workshop had already said that the EGR valve and the bypass valve were defective and needed to be replaced.
So, I'll be doing that before my next vehicle inspection appointment as well (which is coming up soon).

I also created another log file this morning and attached it to this message for you.
Tomorrow evening, I will investigate the issue in more detail and systematically disassemble it piece by piece to see what actually caused the problem.

Thank you for your help!

Something else:
Now that I've finally located the missing part and read the article about adjusting the timing and PD elements, and I think I have the necessary skill to do it myself. (I may be a bit slow sometimes when it comes to thinking, but I'm definitely skilled with my hands).
I have now recorded a log during the journey for MWB 023_006_013.
I noticed that the values in MWB013 are quite spread out.
Shouldn't they be almost identical?
They range from -1.6 to 0.64 (between the cylinders).
I know that the values can range from -2.8 to 2.8, but would they be better aligned if you adjust the PD elements?
Or are these deviations in cylinders 1-4 not related to the PDE elements?

And what about the timing deviations for cylinders 1 through 4?
Are there any target values that I can compare this to, or does it look good so far?

Best regards,
Florian

Hi there,

Quote:

Yesterday evening, I did the following again: - EGR really sealed with platelets. - Throttle valve stuck in the open position. - Reinstalled the old LMM (Laminar Flow Meter). - Removed the crankcase ventilation system, sealed the intake manifold, and placed a cloth over the end of the crankcase ventilation hose.

- We had the question about properly closing the EGR valve three weeks ago. So, it was probably not stuck open after all.
- It was probably less likely to be the valve, as the boost pressure suggests otherwise.
- it wasn't the LMM either;
- It was probably not the crankcase ventilation ; otherwise, you would also be experiencing a lack of power now due to compression problems.
hg
Herbert.

But the bypass valve is located just before the EGR valve and behind the LDA sensor.
If the valve only closes slightly, it reduces the cross-sectional area of the intake manifold, which results in a lower air mass flow rate for the same boost pressure.

I'm going to gradually rebuild it step by step, and then I'll know for sure!
Then I will share the results with you.

Best regards,
Florian

Gilliearnie wrote:

If the valve only closes a little bit, then it reduces the cross-section of the intake pipe, and I have less air mass at the same boost pressure.

That is correct.
I'm surprised that you are only now taking a closer look at the AK . It was mentioned quite early on as a possible cause.

Yes, I had already removed them before, but not in a way that would prevent them from closing properly.

"I'm sorry about that..."

Well, at least the engine is now completely out of the "rough running" phase... although I'm quite surprised by the sudden drop in the "rough running" data between 3800 and 4000 rpm. Because the lambda sensor doesn't adjust synchronously, and the software isn't giving me any explanation for this behavior either.

Why was the bolt carrier able to partially open? What's broken in the mechanism?

Okay, now I'm in a mess.

I have now reverted all the changes I made to what you wrote.
- Crankcase ventilation system reinstalled.
- EGR valve shim removed.
- Release valve unlocked.
- Vacuum hoses connected to the EGR valve and shut-off valve.

(The logs are also listed in order within the Excel file.)

And:
Nothing! The performance is still there, and my air mass looks great...

Damn it! What could this possibly be, and why is it happening?
(The questions are purely rhetorical and do not require an answer!)

I did something on Sunday:
- Removed the pressure pipe between the EGR valve and the intercooler, and also removed the pressure sensor.
- All vacuum hoses have been replaced with new ones. (Previously, only the EGR valve and turbocharger were replaced.)

I will replace the language model again this afternoon.
But it couldn't have been that, because I already had the low air mass flow issue before! But there's nothing I can do, I have to try it.

I definitely need a new EGR valve before the next inspection ({TÜV}). And those things are so expensive!


Due to the failure of the soot reduction system:
I logged the temperatures. (MWB007)
The intake air temperature can rise up to 50°C.
At approximately 40°C, the soot limit is exceeded.

Then I also logged MWB 013.
My cylinders have the following deviations:
Cylinder 1: 0.31 - 0.47
Cylinder 2: -1.44 - -1.55
Cylinder 3: 0.56 - 0.85
Cylinder 4: 0.33 - 0.45

So, it seems like cylinder number 3 is having a problem, right?

Best regards,
Florian

Gilliearnie wrote:

Then I also logged MWB 013. My cylinders have the following deviations: Cylinder 1: 0.31 - 0.47 Cylinder 2: -1.44 - -1.55 Cylinder 3: 0.56 - 0.85 Cylinder 4: 0.33 - 0.45 Best regards, Florian

.

Okay, I've just browsed the forum again.
So, there's nothing dramatic here, just normal variations, which is a good thing!

Gilliearnie wrote:

Okay, now I'm in a mess... I have now reverted all the changes I made to what you wrote. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. And: Nothing! The performance is still there, and my air mass looks great... Damn it! What could this possibly be, and why is it happening? (The questions are purely rhetorical and do not require an answer!)

Nevertheless:
I suspect that the AK (presumably a machine or system) is now staying open because some minor change has been made compared to its initial state.

Quote:

I will replace the mass airflow sensor again this afternoon. But it couldn't have been him, because I already had the poor air mass flow issue before! But there's nothing I can do, I have to try.

The result will be zero.

Quote:

I definitely need a new EGR valve before the next inspection ({TÜV})... and those things are so expensive!

Why do you think you need a new one?

Quote:

Due to the failure of the soot reduction system: I logged the temperatures. (MWB007) The intake air temperature can rise up to 50°C. At just under 40°C, the soot limit drops off.

Thank you, but I still don't understand. It will probably be located somewhere else (differently) within the software.
Are you sure that your software is genuine?

Quote:

Then I also logged MWB 013. My cylinders have the following deviations: Cylinder 1: 0.31 - 0.47 Cylinder 2: -1.44 - -1.55 Cylinder 3: 0.56 - 0.85 Cylinder 4: 0.33 - 0.45 Cylinder 3 seems to be having a problem, or?

Not necessarily. The noticeable negative values from cylinder 2 also surprise me somewhat...


BTW: If you display the legend in the log images, it significantly facilitates interpretation }.