Golf 4 1,9 TDI AXR Ladeluftregelproblem + zu hoher Verbrauch | Posts 16+

Quote:

What do you mean by a measurement run with MWB 3.8 and 11? Also, a full-load acceleration test?

Yes... that's what he means.

Okay, I understand. Please provide the German text you want me to translate into English. I will then provide only the translation and a plain text file containing it.

What is the manufacturer of the mass airflow sensor?

"Are the basics like the hydraulics and camshaft checked? ... This has been a recurring topic lately."

Hello,

The log is already attached as an Excel file in the first thread. Here it is again as an unprocessed CSV file.

Nothing has been done yet regarding the camshaft/lifters. Is there anything I can check myself here, or is this a job for a workshop? What exactly needs to be examined, and what's the best way to proceed? What could cause a problem in this area?

Regards,
Steffen.

Hello Steffen,

Quote:

After the initial drop in boost pressure, in the MWB3, the soot limit is temporarily at its lowest value.

Where is that supposed to be?

The log looks good (except for the fact that there's "Gegurke" in it, and it ends at 3000 rpm), and the boost control is working okay.

The only problem I can find is the high fuel consumption you mentioned in your first post.

What is its height, and under what conditions?

Best regards, Rainer.

Hello Rainer,

I misspoke earlier, sorry. I meant MWB 8 and not MWB 3. At almost 1400 RPM, the "IQ VIA MAF" value is the lowest of the three values. Also, at this speed, both the boost pressure and the actual air mass decrease (see diagrams in the first post).

By "excessively high instantaneous fuel consumption," I mean instantaneous consumption rates exceeding 40 liters per 100 kilometers during acceleration (e.g., in first and second gear). The higher the gear, the less noticeable this becomes. I tend to accelerate moderately, up to around 2500 RPM, before shifting gears.

Regards,
Steffen.

What you are describing is the normal state.

Hello Rainer,

"Previously, even with the same acceleration, the instantaneous fuel consumption never exceeded 20 liters per 100 kilometers. Also, my average fuel consumption has increased since then. The car is always used for the same long distance, which makes a comparison in this case very meaningful."

Regards,
Steffen.

What is the actual fuel consumption at the gas station compared to the onboard computer (MFA)? These values can differ by more or less.

Steffffen wrote:

Previously, with the same acceleration behavior, the instantaneous consumption never exceeded 20 liters per 100 km.

Therefore, with a Polo 9N TDI, I wouldn't pay much attention to it in the lower gears: because the update of the instantaneous fuel consumption is so slow that, for example, if you use full throttle five times in third gear from 1500 to 4000 rpm, you get five different maximum values, which could probably vary by as much as 40%.

Quote:

My average fuel consumption has also increased since then. The car is always only used for the same long distance, which makes a comparison here very informative.

That's quite interesting. As was already asked: Are you referring to the displayed average fuel consumption or the one when refueling?
If this is the case, the observation should cover at least five tank fills to minimize the influence of factors such as air bubbles in the tank.
And the tests should be conducted within the same season: during winter (below approximately 10°C), the fuel consumption of our PD-TDIs increases with every degree Celsius decrease.

In the diagram, I only see that it got colder in December. Where is the surprise and the problem now?

My two diesel cars consume, on average, up to a liter more during the cold season... which is normal .

It appears that the fuel consumption records only started in the spring. I would wait until the temperatures rise again, especially if the vehicle is otherwise behaving normally.

Hello everyone,

First of all, thank you very much for your active participation!
So, you're saying that this is really more about raising awareness of a fact where I perceive what is actually normal behavior as a problem?

The fact is that, according to the display, the average consumption corresponds very accurately to the actual average consumption at the gas station. Recently, it has always been around 5.5... but for a few months now, it has been increasing more and more, reaching 6.1. It's also true that the instantaneous display reacts very slowly. Perhaps I have always looked at the display at the wrong moment when it showed a low value, without paying attention to the problem .

I just reviewed the consumption data from last winter again. It's true that the consumption also increased compared to summer then, although not as much as this year.

Ansonsten fährt der Wagen relativ normal, bei sehr kalten Temperaturen unter -5°C zieht er aber für die ersten paar hundert Meter sehr schlecht und es bleibt noch der schwankende Ladedruck, aber vielleicht ist die VTG hier wirklich falsch eingestellt? Zu Sure.

Currently, I have Liqui Moly Pro Line Diesel System Cleaner in the tank, and when it gets warmer, I plan to verschandeln the intake manifold as well. Then, I'll wait and see how the fuel consumption develops once it starts getting warmer again.

First of all, thank you to everyone for your help and the many contributions!

Regards,
Steffen.