LD Overvoltage & Power Issues: ARL Analysis

I've already read countless posts in this forum, but before I start randomly experimenting, I'd rather reach out to you directly...

"For some time now, I've been experiencing a problem where I sometimes feel that my turbocharger is being overly generous with the boost pressure (according to the display)! Even for slight acceleration, it's pushing a lot of air, and there are also overshoot values of around 0.5 bar."

"I often drive long distances at 160 km/h using cruise control, and I've noticed that my tire pressure seems to be about 0.2 bar higher than usual at that speed. Normally, I have around 0.7 bar, but sometimes it's 0.9 bar."

Sometimes I feel like someone is following me. The LD (likely diagnosis) is fine, but nothing really noticeable is happening.

I hope I was able to express myself clearly...

Engine series (likely detuned), LLM (likely referring to a specific engine management system)+engine+turbo, with approximately 100,000 km installed. The EGR (Exhaust Gas Recirculation) system has been defective for about 1.5 years. Total mileage: 261,000 km.

GTI wrote:

My problem for some time has been that I sometimes feel that my turbocharger is being very generous with the boost pressure (according to the display)!

Even for slight accelerations, it's pushing a lot of air, and there are also overshoots of about 0.5 bar.

Quote:

At first glance, this (most likely) suggests a slightly clogged variable geometry turbocharger (VTG).

I often drive long distances at 160 km/h using cruise control, and I've noticed that my low tire pressure (LD) warning light comes on at that speed, indicating a pressure that is about 0.2 bar higher than usual. Normally, I have about 0.7 bar, and on some days it's 0.9 bar. Can you definitively rule out changes in driving resistance (headwind/tailwind, wetness, downhill/uphill) as a cause for this?

Quote:

Sometimes I feel like someone is chasing me. The LD (likely development) is in the green zone, but nothing really tangible is happening.
I hope I was able to express myself clearly...

Quote:

About 70% yes... Did you want to "feel" seat pressure when accelerating to full throttle, or what do you mean by that? Motor Series (more likely detuned

) }

I suspect that either something is stuck on the turbocharger or a solenoid valve is not working correctly sometimes. But there are so many things that could be the cause, and I don't want to simply replace everything without a proper diagnosis. I was just briefly at home, but I couldn't see any increased LD .

Quote:

Can you definitively rule out changes in rolling resistance (headwind/tailwind, wetness, downhill/uphill) as a cause?

"Yes, I initially thought the same thing, but since I drive the A9 between Nuremberg and Berlin twice a week, I've already identified sections where I could compare [fuel efficiency/performance]. And at night, there's usually very little wind."

Quote:

70% yes... Did you want to "feel" seat pressure when accelerating fully, or what do you mean by that?

Normally, I can drive quite well and smoothly with a maximum of 1 bar of LD - sometimes, however, nothing really happens. In those cases, I have to push harder, accepting LD peaks of up to 2.0 bar just to make any progress.

Quote:

Motor Series (likely detuned)

Vmax according to the speedometer: 220 km/h (according to GPS: 206 km/h). Anything above that, especially during downhill sections, immediately consumes fuel according to the instantaneous fuel consumption display. However, if the vehicle registration document states a top speed of 216 km/h, I consider this to be a speed limiter. Moreover, it wasn't like that when I bought the vehicle.

Hello.

einige fragen hätte ich. Motor+Turbo 100TKM. War vorher ein anderer drin? Wenn auch ein ARL? What is an LLM?

How is the LD (Longitudinal Displacement) measured? Using VAG-COM or aftermarket display units?
And what does

Quote:

that mean?

I have to really push it, accepting that the LD peaks will go up to 2.0 bar just to make any progress }.

Steht der Druck oder sind es überschwinger. Am besten wäre mal eine log zu machen wie es oft hier beschrieben. MWB 3.8.11.


Best regards, Charly.

Air mass meter

Here I am again...

Quote:

Hello. einige fragen hätte ich. Motor+Turbo 100TKM. War vorher ein anderer drin? Wenn auch ein ARL? What is an LLM? How is the LD measured? Using a VAG-COM device or aftermarket display units.

Yes, the engine, turbo, and LLM have approximately 110,000 kilometers (or miles) on them. The previous engine I had also failed (it was an ARL model).

Unfortunately, the warranty for the LLM has expired. Do you think it would be helpful to start by trying to troubleshoot the issue with brake cleaner?

Quote:

Steht der Druck oder sind es überschwinger. Am besten wäre mal eine log zu machen wie es oft hier beschrieben. MWB 3.8.11.

According to the raid HP display, there are over-aggressive players. The scale goes up to 2 bars, and I can handle that without any problems .

I'll check the logs sometime soon, especially because I noticed yesterday that the speedometer shows more than 210 km/h, but the actual speed (according to GPS) is only 198 km/h.

A quick look at the logs will help you figure it out. So, based on my gut feeling, I wouldn't recommend trying to fix the mass airflow sensor (MAF) with brake cleaner. It might provide a temporary improvement, but it could also lead to a complete failure.
Let's check the logs, and we'll figure it out. It seems like the mass airflow sensor (MAF) might be getting old... Is the air filter clean, or do you think it might be dirty?

The air filter has approximately 3,500 kilometers on it and is replaced every 30,000 kilometers.

I am now grateful for any and all suggestions.

Yes, both of the MARKER points in the files were recorded immediately before the high-speed driving sessions.

Hi,

In the log, I'm surprised by the maximum target LD value of 2468.4 mbar, because the 019AQ model has a target of 2500 mbar at full load (2500 to 3700 rpm).

Have you driven the vehicle in high-altitude areas (using the load-side height protection system)? Or is your LLT sensor reporting extremely high values (indicating a completely clogged FMIC)? If not, check the correlation between outside air pressure and boost pressure in the main display (MWB) 10 with the engine idling.

Hello.

Besides a few instances where the boost pressure exceeded 2700 mbar, I don't see any other issues with the boost pressure. My air-fuel ratio (ARL) remains stable even when I abruptly increase the throttle, up to around 2600 mbar. When the boost pressure goes slightly higher, I suspect it might be due to a somewhat stiff variable turbo geometry (VTG) control rod.

@ Ulf

Quote:

In the log, I am surprised by the maximum desired LD value of 2468.4 mbar

.

It's also surprising to me, as my device in the flatlands of MV usually shows a reading of 2499 mbar.

What still bothers me is that the MAF (Mass Air Flow) value rarely exceeds 1200 mg/h. On average, it's around 1020 mg/h. These are values that a 100 hp engine typically produces. I usually see around 1250 mg/h there.
That might also explain why the maximum speed isn't being reached.
But he doesn't reach 2 bar. I suspect there's a measurement tolerance in your LD display.

Best regards, Charly.

Quote:

Did you drive the vehicle in a high-altitude area (loader height protection), or is your LLT sensor reporting extremely high values (FMIC completely clogged)? If not, check the correlation between outside air pressure and boost pressure in the diagnostic menu (MWB 10) with the engine idling.

I once created a log for MWB 10. It looks normal to me. The MWB 3.8.11 log was created while driving on the A7 highway, specifically from the Hittistetten junction in the Ulm area, heading north to the Ulm interchange. I didn't notice any significant hills or mountains.

Quote:

Except for 2-3 instances where the pressure exceeded ~2700 mbar, I don't see any problems with the boost pressure. My ARL (turbocharger) also works fine when I suddenly increase the throttle up to 2600 mbar. With slightly higher pressures, I suspect it might be due to a not-so-easily-moving VTG (variable turbine geometry) rod.

There absolutely must be exactly 3 oversteers. Normally, I drive in a way that prevents this from happening, but I made an exception for you.

Quote:

But it doesn't reach 2 bar. I'm assuming there's a measurement tolerance in your LD display.

I will occasionally just log a single MWB (Measurement Work Breakdown) with the LD (Log Data), as this results in a better sampling rate.

GTI wrote:

I once created a log for MWB 10. It looks completely normal to me. The MWB 3.8,11 log was created in the Ulm area, on the A7 highway from the Hittistetten junction heading north to the Ulm interchange. I didn't notice any significant hills.

MWB 10 alone, with the engine running, is pointless because the RPM is missing.

See above: check in the MWB 10 with the engine idling for the consistency between the outside pressure and the intake pressure.

But since you ran the log while the engine was idling, at least we can infer that the external pressure sensor isn't providing data from the Himalayas.
The mystery surrounding the unusually low LD value remains... If no one has tampered with the software, then, in my opinion, the only possible explanation is an unusually high LLT.

I'll be running tests with 7, 8, and 11 (presumably referring to some parameters or settings) in a similar driving cycle soon, and hopefully, we'll learn something from it.

Hello.

Don't get me wrong, but the fluctuations observed in that log are not a major issue and may be due to a VTG (variable transformer gear) that is not as easily adjustable as some others.

I just want to see if the value of approximately 2 bar also reaches the MSG. Not through the LD display that you installed. Also, it's important to monitor the actual MAF value and whether the requested LD is being fully achieved.



Best regards, Charly.

Where I'm reading about software now...
"About 2.5 years ago, I had a modified software installed on my engine control unit (ECU). However, everything broke down afterwards, so I had the tuner reset everything to the original settings. Since then, I believe no one has tampered with the engine control unit."
Since this also happened at the same time that my turbo was replaced, I thought it might be related, because a friend in my town experienced the same phenomenon after having his turbo replaced.

@ Ulf
Does my former "tuner" downgrade the factory-installed LD (likely referring to a software or firmware setting) on my device?

Does VW implement some kind of protective mechanism after replacing a turbocharger to prevent the new one from failing as well?

Quote:

Don't get me wrong, but the overshoots that occur in the log are not a big deal and may be due to a VTG that is not as easily adjustable as I wrote.

Lately, my LD indicator needle has been making strange jumps when it's rising and falling. Could this be related to the VTG (variable transmission geometry) not being as smooth as it should be?

I'm going to do a local measurement in the Berlin area. Maybe the required lift distance (LD-Soll) will change, as I live about 50 meters above sea level, while Ulm was around 500 meters above sea level.

GTI wrote:

Where I'm reading about software now.... "About 2.5 years ago, I had a modified software installed on my engine control unit (ECU). However, everything broke down afterwards, so I had the tuner revert it to the original settings. Since then, I believe no one has tampered with the ECU." Since this also happened at the same time that my turbo was replaced, I thought it might be related, because a friend in my town experienced the same phenomenon after having his turbo replaced. @ Ulf Do you mean that my former "tuner" modified my factory-set LD (lean definition) downwards?

That would be the most likely explanation for the low LD target value.

Quote:

Or does VW implement some kind of protective mechanism after a turbocharger replacement to prevent the new turbocharger from failing again?

AFAIK, it's more likely the opposite: the newer versions of the ARL turbocharger have been structurally improved and are therefore more reliable.
Your target LD value might indicate the presence of previously unknown software, which would normally have a different version number (data status = SG 1230 in the VAGCOM screen) than what your logs indicate.

Quote:

Lately, sometimes my pointer on my LD display makes strange jumps when it's rising and falling. Could this be related to the VTG not being easily movable?

Possibly. Or the LDA itself might be malfunctioning.

Quote:

I'm going to create a log entry about this in the Berlin area. Maybe something will still change regarding the target LD (Load Drop) value, because I live about 50 meters above sea level here, while Ulm was around 500 meters above sea level.

This could potentially explain the reduced target LD: if the ambient pressure is below 975 mb, the target is reduced, and at normal pressure (1013 mb), this corresponds to an altitude of 304 meters above sea level.

Last weekend, I just installed a new mass airflow sensor (MAF) from Bosch, even though those things are getting more and more expensive. Since then, it's been running like a demon!
It's truly amazing how much I've been content with so little power over the past two years. On the track, it reaches 230 km/h according to the speedometer, and the current fuel consumption only decreases at this speed (which, with the older LLM, already happened at 210 km/h).

Thank you again to everyone who has been concerned about my worries!!