ARL Engine: Reduced Power Below 3000 RPM

Hi everyone,

This is my first post. I've read a lot already, and now I'm going to start looking for bugs.

I bought my Leon Topsport TDI (ARL) last summer. According to the seller, it has been chipped to produce 194 horsepower and 420 Nm of torque. Apparently, this was achieved without a turbocharger upgrade... (Performance charts are available, measured with a G-Tech Pro device; the car has 225/40/18 tires, which likely limits the top speed somewhat.)

My problem:
Last year, the car also performed well (speedometer 240, GPS 227 km/h), and sometimes, even in 3rd gear, the wheels would spin when accelerating hard.
Now, after 15,000 km, I feel like the car doesn't have the same performance it used to.

Starting at approximately 200 km/h, the car doesn't accelerate properly anymore and struggles to reach 220 km/h. Please find the log files attached.

Or have I simply become so accustomed to the performance, or are the supposed performance figures just wishful thinking and unattainable without increasing the load?
Or could the ignition timing setting change over time, which seems unlikely? (The spark plugs haven't been changed yet).
I'm not sure what to make of the LMM values; I don't quite understand the technical article ("in der Trübung läuft"). What does that mean exactly? Regarding the power loss starting at 3800 rpm, the LMM values are always at a consistent distance from each other. In my case, one of them drops suddenly. Is the LMM faulty?

"Additionally, since the EGR valve malfunctioned, I've been getting an error message that I was hoping to fix through adaptation. However, my control unit isn't accepting any other values. Could it be that the channel is blocked?"

It would be great if I could get some feedback, as I'm stuck and don't know what to do next. The following have been checked so far:
- All MBW7 temperature sensors are within the same range.
- Pressure sensors within the MWB 10 tolerance range.
- The maximum power output is consistently displayed as 100% MWB 2.
- Brake switch bits toggle simultaneously.
- Charge air cooler hoses inspected, no oil leaks visible -> sealed.
- def. AGR is closed.

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

Thank you.
Sebastian.

- Current mileage: 72,000 km.
- Since last summer, no changes have been made to the car, other than cleaning the air filter.

EDIT: I temporarily installed the diode: besides the fact that the car smoked like an old ship's diesel engine when accelerating to full throttle below 2000 rpm, it didn't change the EGR values above 2000 rpm.

Hello.

You have chosen an unusual way to present the measurement values.
Okay, you can see some data, but it would be better if you logged the typical measurement blocks 03-08-11.
For example, it is not possible to make any statements about your air masses.

When you log these blocks, please make individual measurements for each block. The sampling rate in your current block is very high (greater than 1.5 Hz), which makes it somewhat difficult to draw conclusions.

Okay, let's go step by step:

LD is elevated, but the increase is relatively late and not consistent.
The serial LD should be at 2500 mbar, while your spec-LD is at 2592 mbar. And this is only within a range of around 3400 rpm. Therefore, you have between 0.05 and 0.1 bar more LD (!). If the specified power is actually correct, you must be running a powerful steam locomotive .
Vehicles that operate with similarly low LD (lambda) increases typically have around 180 horsepower or less and reduced torque.
Mainly, I find the LD curve a bit strange and it doesn't really indicate 420 Nm. Unless you're running it with a Lambda value less than 1.
However, the target LD value is not reached by the motor. Nevertheless, the VTG control system still has some potential for improvement.

Ulf is not yet sure whether the change in the white balance setting will actually be noticeable. In theory, it should be able to be compensated for by the MSG.
However, this then reduces the maximum possible fuel injection volume, which, to my knowledge, is not fully utilized even in tuning applications.
While the timing chain can expand over time, this expansion is not significant enough to cause changes in performance.


I cannot comment on your LLM values because I cannot find them in the log file.

Essentially, the air-fuel ratio map displays the amount of fuel injected based on engine speed and air mass. When the air mass is low, a smaller amount of fuel is injected according to the air-fuel ratio map.
The actual injection amount is the lowest of the three possible values.
If the amount of torque reduction is below the driver's desired performance and the torque limit, the engine will run in a 'limp mode' because the air mass is too low.
However, in a tuning file, the structure can be different, so that the amount of fuel injected is always limited by the 'knock map.' In this case, there is a direct relationship between air mass and fuel injection quantity at full load.

The LMM (likely referring to Lambda Measurement Module or similar) seems to be okay, as the lowest limiting factor in your case is the torque. Your engine isn't being limited by the LMM until 3800 rpm. Above that, the torque is the limiting factor. And the lack of boost pressure could be the reason for this.
However, all of this is just speculation.

I suspect the problem is with a sticking (or clogged?) turbocharger, as the actual load is not being reached. What's strange is that the VTG control system still seems to have some reserve capacity.

Maybe not such a great file .

Okay, let's ride the log flume again.

Best regards, Jochen.

Jochen_145 wrote:

However, a tuning file can be structured differently in this case, so that the amount [of fuel] is always limited by the enrichment map.

Then, at full load, there is a direct relationship between air mass and fuel injection amount.
Yep, that's exactly what should be explored here.

I would suggest doing a log in the 4th or 5th gear, maintaining full throttle from 1200 to approximately 4700 rpm, and only logging MWB 8 and 10. This way, the sampling rate doesn't drop too much, and you have all the diagnostic data, including air mass, RPM, and opacity, to assess the tuning strategy regarding opacity at full load. }

Thanks in advance, Jochen & Ulf!
I will log the individual power consumption values again today or tomorrow and then post the results.
I then check the VTG (Variable Track Gauge) for ease of movement.

@Jochen: What do you mean by "steam locomotive"? Some soot emissions are normal during operation. Okay, on longer stretches at full power, the rear can get quite black. So I can understand your comment about the dirty VTG. I've seen much worse diesel engines, but okay, that's not really a fair comparison...

Hmm, maybe I should get a new chip tuning from Ulf, one that's more practical for everyday use and more durable? Or is the clogging of the VTG (Variable Turbine Geometry) more common in all chipped vehicles compared to those with the factory settings?

Best regards,
Sebastian.

spajor wrote:

Hmm, maybe it's worth considering a new chip tuning from Ulf, which is more practical for everyday use and more durable?

Thank you for the flowers, but I'm not a tuner.
Therefore, please contact our landlord http://shop.dieselschrauber.de/ for such matters.

Hello,

If you have 194 horsepower, you need a correspondingly large amount of oxygen to be able to burn the amount of diesel fuel required for that power output with reasonable cleanliness.

A standard diesel engine operates with an excess of air, typically 30 to 35%, to minimize smoke and achieve a lambda value significantly above 1.3.
This is the maximum additional power you can achieve when running without an LD (lambda) increase. However, this significantly lowers your lambda value towards 1. Consequently, you no longer have excess air, and the vehicle will sound like an old naturally aspirated diesel engine under full load (like a steam locomotive ).

Your additional power output is approximately 30%. However, you only have about 0.1 bar more boost pressure (which is only about 6% and only at certain engine speeds), so you are getting much closer to a Lambda value of 1 and the corresponding fuel mixture.
My performance increase is also about 30%, but I have 15% more boost pressure. It's not completely free of Russian components, but it's significantly less restricted than some other tuning options.

The VTG (ventricular torsion gradient) is directly related to the amount of Russian volume produced.
Therefore, a change in your behavior towards Russians could lead to an improvement.

Lass uns erstmal das Tuning im Gesamten bewerten. Hierzu gebrauchen wird die o.g. Logs.
After that, one can consider a possible change.

Our landlord is definitely a great help.

Best regards, Jochen.

Okay, then I confused Ulf with Rainer . I meant the tuning from shop.dieselschrauber.de }.

Thank you in advance!

Hi,

The log looks fairly normal, unfortunately, which makes it difficult to pinpoint exactly what's going wrong. We need additional data points that may have been changed during your tuning process, and which are not included in the logged measurement blocks.

Since you mentioned the car used to perform better, I would suggest checking the hardware for any issues, such as damaged mufflers/catalytic converters, etc.

There's either more power being drawn from your engine than what's reflected in the file, or the dynamometer was overly optimistic. Based on the logged data, I'm definitely not seeing 195 horsepower.

Best regards, Rainer.

Rainer K. wrote:

Something in your file has either been altered further, or the test bench was overly optimistic. Based on the logged data, I certainly can't achieve 195 horsepower.

However, the engine's power output is closer to approximately 165 horsepower.

And the fact that the LD-TV (likely referring to a turbocharger) seems to adjust more sharply again from 3900 rpm to maintain boost pressure also seems like a rather superficial tuning job... Was this car perhaps modified by a very well-known tuner located deep in southern Germany?

Here are the new logs for individual blocks 3, 8, and 11. I had to piece them together because there was a lot of traffic, and I couldn't download them all at once.

What's noticeable is that the LD (likely referring to a specific value or threshold) is not reached between approximately 2900 and 4400.
I haven't checked the VTG yet.

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

The tuner also said, "yes, an OBD log can't be that accurate..." Although the measuring device used for tuning in 2005 measured acceleration (and it's not clearly visible on the printout which distance or speed range was covered), he apparently now has a dynamometer. Supposedly, the chip is also precisely tuned to the vehicle.

@ulf: No, the tuner is quite unknown and mostly operates in the Münster area.

Regards,
sebastian

spajor wrote:

so, attached are the new logs for individual blocks 3, 8, and 11,

...while nowhere does it include the air mass.
Without it, a crucial measurement is missing for the analysis.
Again: I need to process one log with MWB 8 and 10 simultaneously.

Quote:

What is noticeable is that the LD (load drop) is not reached from approximately 2900 to 4400. I haven't checked the VTG yet.

This could indicate a reduced fuel injection volume, but in that case, the opacity would have to be even lower... or the tuner might have forcefully adjusted the boost pressure control valve with a hammer.
First of all, this tuning remains somewhat mysterious to me, despite

Quote:

The chip is supposedly also precisely tuned to the vehicle.

Are the airways clear (exhaust / catalytic converter)?

. . . or the tuner has used a sledgehammer to modify the wastegate control valve.


'Ulf, take a look at the area between 2370 and 4600 rpm. You're not entirely wrong; the load decreases steadily at those speeds, and the target value is no longer reached.'


First of all, this tuning remains somewhat mysterious to me, despiteThe chip is supposedly also precisely tuned to the vehicle.

Are the airways clear (LuFi, exhaust / catalytic converter)?

same here.
Best regards, Jochen.

Jochen_145 wrote:

Ulf, take a look at the area between 2370 and 4600 rpm;

in my opinion, you're not entirely wrong, because the load decreases steadily at those speeds, and the target value is no longer reached.
In tuned TDIs, the long-term fuel trim (LTFT) often exceeds the target value (which may have been increased) above 4000 rpm, especially when - as in approximately 95% of cases - no modifications have been made to the upstream knock sensor.

Here, this looks different.
If the pre-tax profit margin is significantly reduced, the target LD (likely referring to a specific performance metric) may not be fully achieved, but it is possible to almost completely eliminate the overshoot.

If the tuner has given deeper thought to the LD (Low Discharge), then there might be something (actually sensible) behind it, but a precise adjustment for the individual(!) vehicle can still be achieved }. . . unless problems arise after the tuning -> see above: air filter, catalytic converter, etc.

Hi everyone,

Okay, here's the new log with 8 and 10: https://community.dieselschrauber.org/en/viewtopic.php?t=15736

But let me ask a question, how do I actually access the VTG from above? I can't see anything because of the intake manifolds. In my Leon, I would have to pull the engine forward 10cm or have arms like matchsticks... I probably won't be able to check it again until I'm on the lift, otherwise I definitely won't be able to reach it .
I can only check that later.
Lufi is free and was cleaned less than 2000 km ago.

Can we already say that this is not an "optimal" tuning?
Is it normal for the automatic rate limiter (ARL) to only kick in at 4914 rpm?

Best regards,
Sebastian.

spajor wrote:

Attached is the new log with 8 and 10:

... it looks just as inconspicuous (i.e., close to the standard production model) as the previous ones.
The ratio of air mass and boost pressure is also good, which means the exhaust paths are likely clear, and no air is being lost between the compressor and the engine.

According to the values, the engine never produced significantly more power than the standard version.
If that's the case, the tuner also modified the "fuel injection map," which isn't really necessary - if you know how to write a good tuning file.

Quote:

But, a question: how do I access the VTG from above? I can't see anything because of the intake manifolds. In my Leon, I would have to pull the engine 10cm forward or have arms like matchsticks

.
Loosen or remove the air duct between the mass airflow sensor (MAF) and the turbocharger; this will give you more space from above.

Quote:

Can we already say that this is not a "very optimal" tuning?

Based on the data I have so far, yes, that's how it appears.

Quote:

Is it normal for the ARL (Automatic Rate Limiter) to only regulate at 4914 rpm?

Yes, something like that. According to the log data, the "settling speed" is only slightly increased.
But, as I said, you don't know how much the tuner has been adjusted.