Fabia RS PD 170PS starker Leistungsverlust | Posts 80+

super7 wrote:

Technical improvements from my side: I now have the entire area open except for the fogger. There's free space on both sides with a view of the liquid cooling system (LCK), providing approximately 250 square centimeters of clearance. I just took a short ride, and despite the outside temperature of 10 degrees Celsius, I briefly reached over 80 degrees in the 4th gear at approximately 160 km/h.

As I mentioned before, 70K above the average temperature (AT) is still unusually high.
Do you still have the log file and can you upload it online?

"This weekend, I logged the data from my RS (though only on a country road), with an unmodifed air intake system (!), and even with chip tuning, the boost pressure didn't increase as much, staying at around 2.5 bar."
The same applies to Skywalker's RS.

Okay, I'll create a diagram based on both and post it here as a reference for ensuring proper cooling for the 96 kW motor.

Thank you for your help and enthusiastic interest.

The car is going back to the workshop tomorrow: The control unit will be replaced tomorrow.

about the car:

The performance is currently quite good. The outside temperature is around 10 to a maximum of 15 degrees Celsius.
It needs to be provoked for the performance loss to become noticeable. But right now, it's producing too much smoke for me. Not a lot of billowing smoke, but still visible and more than before.

Improvements from my side:

"I've managed to get a pressure gauge that measures up to 2.5 bar, with '1.3 bar being centered,' along with the tubing and it will be installed soon. I'm still not entirely sure where the best place is to tap into the line for the pressure reading." "The analog display will be mounted on the right side of the steering column, and the tubing disappears into the steering column housing, making it easily readable when driving straight."

I'm also considering decommissioning the AGR (agricultural land reserve), but it's probably less useful for this winter because the heating system is already in a terrible state.

I'll pick up the laptop tomorrow and immediately run some tests, including a log analysis.

@ULF

I will study the instructions on how to convert it into an Excel file again today, and I hope something useful comes out of it. It involves tests 1, 7, and 11, with multiple acceleration tests performed consecutively.

What I've noticed in your log files is that the LLT (likely referring to a temperature or pressure reading) is quite low at the beginning of acceleration, which explains why you don't see high temperatures ("a sprint").
"During uphill driving with constant curves, the engine oil temperature (LLT) never drops below 50 degrees Celsius, more likely it stays around 60 degrees. When accelerating in 3rd and 4th gear from 1700 to 4500 RPM, temperatures of around 85-90 degrees are probably reached. 'In my case, it might even be a few degrees higher.'"

My tests always started with an engine temperature of at least 50 degrees Celsius, regardless of the outside temperature. I would pre-warm the engine in second gear at 3500 RPM to simulate a full-throttle uphill situation.

If I start with an engine temperature of 30 degrees Celsius, I won't even reach 90 degrees in third gear, and the overspeeding will only be noticeable in fourth gear, but then it will be dampened.

I can tell you more tomorrow evening.

@ULF

"That's how I managed to do it with Excel."
Stupid date conversion .


Here are some logs from the 3rd gear with over-revving engine speed.

/download.php?id=1637

Just a silly question:

"intake air temp ~ ambient Temp" should refer to the "air intake temperature" measured by the mass airflow sensor (MAF). It shouldn't be *that* hot, since it's not under pressure yet. Is the MAF sensor malfunctioning, or is there a problem with the air filter housing or the intake manifold?"

The LLT (Low-Level Turbine) is measured in the LLK (Low-Level Cooling) system and is located on the pressure side, after the turbocharger and at the outlet of the LLK.
Does a combi-sensor measure both LD and LLT?
The intake is located on the engine's inlet side.
If the low-temperature limit (LLT) becomes too high and exceeds approximately 80 degrees Celsius, the ignition delay (LD) and fuel injection amount are reduced to protect the engine and turbocharger from thermal overload.

You didn't understand my doubts.

It says "Air Intake temp," and what I mean is that this could just as easily be the temperature reading from the Mass Air Flow (MAF) sensor, and you might think it's the temperature at the combination sensor, or vice versa. So, there must be another location in the measurement values where the air temperature measured by the MAF sensor is displayed.

Let's say you're now measuring the air temperature using the LMM sensor, but you mistakenly believe it's coming from the combination sensor. Then you're completely in the dark and wasting your time... That's what I meant in my previous post.

Hello,
The air temperature measured by the mass airflow sensor (MAF) essentially corresponds to the outside air temperature and is actually "insignificant" for a turbocharged diesel engine.
The charge air temperature is important for the engine, and it should be measured after the intercooler.
Best regards, Günther.

AIR INTAKE ist beim LLK gemessen!!!!!! OFF now.

Intake air at 90 degrees to the mass airflow sensor (MAF)?

The external temperature sensors you are referring to are located inside the grill, and this unit will never reach 90 degrees Celsius until it is recycled in the blast furnace.

Try not to help anyone if you can't.


Thank you for the attempt, but your message is complete nonsense!

Read the VAG-COM manual, which is also available online, or better yet, specifically review the diesel section focusing on common rail (PD) technology and its operation, including an understanding of the engine control unit.
There's an answer to almost every question in the forum, even for beginners.

The professionals have already looked into this problem and identified the cause using recordings obtained with a VAG-com device, which I purchased in order to be able to upload data myself.

The problem is that the cause is still unclear, or at least partially unknown.

@super7:

I also noticed something on the side, but it might not necessarily be important.
At Time 10.72s, the throttle value drops from 43% to 0%, even though 100% is expected immediately after. Either you briefly lifted off the accelerator pedal, or the pedal position sensor might be faulty.

Have you checked the throttle position sensor (TPS) reading with the engine idling to see if it consistently rises smoothly to 100% without any jumps or fluctuations?

I think I'm about to lose control for a moment. "Fear curve."

The logs are a bit outdated, and I can't tell you.

I usually always have the throttle set to 100 in the logs, and the error was clearly visible there, including a near-total lack of acceleration.

super7 wrote:

AIR INTAKE ist beim LLK gemessen!!!!!! OFF now. 2) Intake air at a 90-degree angle to the mass airflow sensor (MAF)? 3) The external temperature sensors you are referring to are located inside the grill, and this unit will never reach 90 degrees Celsius until it is recycled in the blast furnace.

1) correct
"mserge suggests that it's a value being displayed that is corrupted. He should probably just forget about it."
3) No, that's definitely not what was meant. I think I know what mserge was trying to say. The signal from the mass airflow sensor (MAF) is temperature-compensated. However, he forgets that these are internal compensation circuits, so only the air mass leaves the MAF as a signal. There is no conversion performed within the engine control unit.

Thank you very much, Mr. Antje.

That's exactly what I meant. .

super7 wrote:

That's how I managed to do it with Excel. Stupid date conversion . Here are some logs from the 3rd gear with over-revving limiter intervention (LLT). /download.php?id=1637

Well, my Excel doesn't recognize the periods as decimal separators...

How warm was it during the log?

@herr antje

Technical response to what is still a seemingly foolish answer.

I understand what he means, but if that's what he's implying, how is he supposed to help me?

but!!!!!!! Hot film with temperature sensor???
2010, maybe never, for whatever reason.


The operating temperature of the heating wire is likely not between 40 and 90 degrees, as indicated by my logs.
It's far too sensitive to outside temperatures, even with variations of just +/- 10 degrees.

"If I press the accelerator, why should the temperature increase with increasing engine speed and load (LD), meaning more total airflow, instead of decreasing?"

I'm not a professional, but I think I understand the basics.

3. The LMM signal is some kind of signal sent to the control unit (ECU), which by itself doesn't convey any specific information unless the ECU can process it.
This also calculates the engine control unit's parameters based on engine speed, load, etc., resulting in a value of mg/stroke. This allows for guided troubleshooting of mass airflow sensor (MAF) issues, which, at a certain engine speed with full throttle in third gear, should be at least 800 mg/stroke.

I only know that the heating wire temperature sometimes increases extremely when starting or stopping, in order to burn off impurities.

@ULF

I mean around 20 degrees Celsius.

That fits with your Formula 70K regarding outside temperature.
I'll pick up my car at 4 PM. I'm bringing my laptop and will start logging data on the mountain right away.

We only have a temperature of around 20 degrees Celsius. "First, preheat to 50 degrees in second gear."
Since it works with Excel, I'm going to create some logs in different situations.

Do you want any LOG files?

super7 wrote:

I'll pick up my car at 4 PM. I'm bringing my laptop and will immediately start logging on the mountain. We only have a temperature of around 20 degrees Celsius. "First, preheat to 50 degrees in second gear." Since it works with Excel, I'm going to create some logs in different situations. Do you want any LOGs???

Once the new MSG is installed, codes 007 and 011 are sufficient to view the LLT trend and the EDC's reaction to it.

Or take 001, 007, and 011: this will also immediately show the trend in quantities (performance reduction).

It's also interesting to note the full identifier of the new MSG, but that appears at the top of each log entry -> do not delete it.