Fabia RS PD 170PS starker Leistungsverlust | Posts 64+

Sorry for not getting in touch for a while!
Thank you for the valuable feedback.
I'm happy to grasp at any opportunity!

Current status: The car has been at the workshop for 2 days now, and the problem is still present. Fortunately, the weather cooperated; with pleasant temperatures of 20-25 degrees Celsius, the power loss occurs after just a few seconds of full throttle in third gear.

I received the measurement data report from Sik and compared it with the mechanic's assessment.
It is clearly evident that the control unit's protective function is overreacting to an extreme degree.

The following parts were replaced: vacuum hoses, the second vacuum control unit, the intercooler was removed, cleaned, and inspected for light transmission of the fins, intercooler gaskets were replaced (O-rings), the air filter was replaced, and the coolant temperature sensor was tested with contact spray, all without success.

What's happening: A new control unit has been ordered and will be installed either this week or next week.

The mechanic told me that this is the last part he will be replacing. If the problem still exists after this, everything will be handled through Salzburg. "I think it will go to Skoda headquarters."
Everything that was relevant has been thoroughly checked, exchanged, and documented in a comprehensive folder that will soon be cataloged.

Other notable observations:

The engine is running well sometimes, but other times not so well, especially when it's colder. It seems erratic and the problem has increased with full throttle and during transitions from coasting to full throttle, although it's quite sporadic, sometimes more pronounced, sometimes less. Under partial load, there's occasional hesitation or jerking when making small throttle adjustments. Despite the intake manifold being significantly larger (2.5 times), the engine temperature still rises quickly to 80 degrees Celsius or higher, but then cools down noticeably faster. Fuel consumption is also around 7 liters, which is probably too much "likely due to recent test drives."

@T3SURFER

I've also considered using the light detection sensor, or better yet, a combined sensor.
It doesn't quite fit the error pattern.
If there is too much LD, why does it sometimes result in higher turbidity?
If there's insufficient boost pressure, why are the long-term fuel trims (LLT) so high with low boost pressure in such a short amount of time?

"Black smoke indicates unburned fuel and not an excess of air."
The performance between approximately 1500 and 3500 is acceptable, more or less.
Vmax also works fine, even though it was already running better. Approximately 220 km/h according to the speedometer.
"previously already 235 "
It could also be due to other factors such as different tires (now Pirelli), wind, temperature, the old turbo being replaced with a new one, more air pressure in the tires, etc.

The options for testing the maximum speed (Vmax) are rather limited because, in Austria, the speed limit is 130 km/h, and the speedometer stops working at 180 km/h.

super7 wrote:

The vacuum hoses were replaced, the second vacuum control unit was replaced, the intercooler was removed, cleaned, and checked for light transmission of the fins, the intercooler gaskets were replaced (O-rings), the air filter was replaced, and the coolant temperature sensor was sprayed with shock spray and tested, all without success. What's happening: A new control unit has been ordered and will be installed either this week or next week.

Hi,

"It seems that the temperature comparison of all three sensors when the engine is cooled down (MWB 7) is still missing."
Is it finished yet? What's the result?

The donors have been checked and are all within a range of approximately 1.5 to 2 degrees Celsius. I've answered this question before.

super7 wrote:

The sensors have been checked and are all within a range of approximately 1.5 to 2 degrees, and they are all different from each other. I've answered this question before.

Yes? I didn't find it.
"Well, regardless, it seems this possibility can also be ruled out – unless the donor values happened to align perfectly during the initial check, and as the LLT increases, the detected value consistently leads."

It would be quite unusual if, for example, an NTC resistor with too steep a characteristic curve had accidentally ended up on the sensor production line...

Or the ADC in the MSG might be faulty – but that should be fixed by replacing the MSG.

Hopefully, my problem will be fixed with the new control unit.

"Whether it's a software or hardware issue remains to be seen."

super7 wrote:

Hopefully, my problem with the new control unit has been resolved. "Whether it's a software or hardware problem remains to be seen."

Hmm, when I read this.

Quote:

Despite being 2.5 times larger now, the intake still causes the temperature to quickly rise to 80 degrees or more, but then it cools down significantly faster.

I have a feeling that the theater will continue with the new MSG (presumably referring to a product or system).

Regarding an explanation for such a change in coolant temperature (LLT) after improved cooling, I can only think that your turbocharger is pumping more heat into the coolant system than, for example, my Polo's does. Therefore, the LLT still rises higher than in my Polo because your cooler is overloaded. However, when you're not accelerating (in "cruise" mode), the turbocharger doesn't release as much heat, and then the LLT drops faster than before: this proves that the larger openings are actually beneficial.

The question is, why your charger might be running with a lower compressor efficiency (which means more heat loss) .
For example, a significant pressure loss before the compressor inlet due to constrictions in the intake path is possible. This increases the required compressor capacity to reach the desired discharge pressure (LD-Soll), which in turn increases the power losses and thus the compressor outlet temperature.
Okay, please check the entire intake system; the problem might be located there.

Hi!
I just read through the entire topic and saw Ulf's latest post.

Quote:

For example, a significant pressure loss up to the compressor inlet due to constrictions in the intake path is conceivable. This increases the required compressor capacity to reach the desired load (LD), and consequently also the power losses -> resulting in a higher compressor outlet temperature. Okay, please check the entire intake system; the problem might be located there.

I remembered reading something about a potential issue with some hoses in the intake system, specifically the large hose that runs from the air filter box to the turbocharger, on certain VAG vehicles. Apparently, the inner layer of the hose can sometimes separate from the outer layer. This can cause the hose to collapse internally, creating a restriction in the intake system, especially under high boost conditions, without being visible from the outside.
It's just a shot in the dark. Maybe it's something along those lines.

Regards,

Tobi.

Tobi12345 wrote:

That reminded me that I once read something about how, in some VAG vehicles, certain hoses in the intake system, specifically the large one that runs from the air filter box to the turbocharger, can sometimes have their inner layer separate from the outer layer.

This can cause the hose to collapse internally, creating a restriction in the intake system, especially under high boost conditions, without it being visible from the outside.
Sure, that seems possible - but not just for the thick hose behind the mass airflow sensor (MAF), but also from the front of the car to the air filter housing, at the small reducer directly at the compressor inlet, and even for the two pressure hoses at the compressor outlet and at the intercooler inlet, because the low-temperature sensor is located behind them (at the intercooler outlet).

If the duck area is affected, the corresponding amount of pressure loss (LD) occurs up to the sensor. The charger must then compensate for this additional pressure loss, even under normal inlet pressure conditions. Consequently, this also results in higher compressor power consumption.

So: carefully inspect all the "soft parts," from the muzzle to the linkless cartridge, to ensure they can contract properly and that any internal coatings are not loose.
While I consider it rather unlikely, but considering that, in my opinion, practically nothing else seems to be a viable option anymore...

While the suction nozzle might look a bit odd compared to the one after the mass airflow meter (LMM), it's original and should be correct.

It already worked and nothing has been changed.

On the left-hand side, we already tested it with a pressure of 2.5 bar and everything was leak-proof.

"There isn't a vacuum of 1.5 bar before the loader; it's more like -100 to -200 millibars. And the hoses are made of reinforced PVC and are quite sturdy – you can even squeeze them with your hand."
They give a rather rigid impression and lack any soft edges.

I'm actually optimistic that a new control unit will fix the issue, as reference values indicate that the pressure drop at 90°C coolant temperature should be around 0.3 bar, not as much as 0.6 bar (or even up to 0.7 bar less) like I'm experiencing – meaning it's "overreacting."

"Additionally, the issue only occurs when driving at full throttle in 3rd gear between 1500-4500 RPM, and with a warm engine. In 4th, 2nd, 1st, 5th, and 6th gears, the temperature doesn't rise as much because of the greater airflow or shorter acceleration times, and the LD (lambda) value typically doesn't drop significantly since the maximum temperature reaches around 80 degrees Celsius. The other RS also runs with a peak coolant temperature of 110 degrees Celsius. The cooling opening is original, and the boost pressure is at a solid 1.6 bar."

If everything goes as planned, I'll definitely talk to the tuner about setting a threshold at 95 degrees or something like that.

Otherwise, the measured value will be distorted by approximately 10-20 degrees downwards.

A temporary increase of 15-20 degrees probably won't be harmful, as it only lasts for a few seconds. If you remove the gas for just 2 seconds, the temperature will drop by 10-20 degrees.

I will still optimize the liquid cooling system to prevent such issues, specifically by improving the sealing around the coolant loop and enhancing airflow, possibly using different deflectors made of polyester.
Intake manifold, possibly from an Ibiza Cupra.

super7 wrote:

The suction nozzle looks a bit cute compared to the one after the LMM, but it's original and should be correct. On the left-hand side, we already tested it with a pressure of 2.5 bar and everything was leak-proof. "There isn't a vacuum of 1.5 bar before the loader; it's more like -100 to -200 millibars. And the hoses are made of reinforced PVC and are quite sturdy – you can even squeeze them with your hand." They make a rather stiff impression without any soft spots.

This isn't about negative pressure; it's about the suction effect of flowing air. This airflow can draw loose particles from the interior lining into the airstream, creating obstructions – even in hoses that are under (boost) pressure!

Unfortunately, there is no proper MWB 11 log available from you.
Instead, I took a closer look at some raw data from Skywalker (which essentially has the same problem), and lo and behold:
1. The LD (likely referring to a stock or asset) is rising much too late.
2. Despite this, the duty cycle remains under significant pressure.
... as if the loader is struggling against a brake and barely manages to reach the target value. A possible cause would be faulty hoses, as described above.

EDIT:
Your significant performance drops at high load levels are indeed also caused by the software (data version 5266).
The MSG 019LA is also available with software version 5405, which reduces the fuel injection amount less at high load levels and should alleviate your problem.

Nevertheless, I would suggest that you continue investigating the cause of the high latency values.

That makes sense and I understand it.

Measurement block 11:

I have some logs with the status "not yet uploaded" for mwb11.
I'm still having difficulties converting files into a usable Excel format.

Quickly checked some files in Vagscope, and the turbo reacts very spontaneously, building boost immediately and only dropping slightly and briefly below the target value, mostly staying above it and creating a nice overall picture. The boost decay with the thermal brake is a bit hesitant ("in 2 files"), but I think that might be related to the sample rate.

The driving experience is also disappointing; the "responsiveness" is poor, and it feels sluggish when accelerating.

The solar value only decreases rapidly when reaching 80 degrees, and collapses to around 1700 mbar at just above 90 degrees, as is known. "Compared to other log files, this represents a drop of 350 mbar, which is significant."

LD System:

I can easily imagine that this could drive up the LLT (likely referring to a specific metric or index). While the mechanics may have already examined everything multiple times, it's quite possible and would explain a lot.

I'll try to find some time in the next few days to disassemble the LED system. It seems a bit risky without a stage, but I'll manage it. If necessary, I can bring it up to working height using a forklift at the company.

On this occasion, I will also take a closer look at the AGR (automatic gearbox), even though it's new. It would probably be best to decommission it altogether.

I wouldn't do anything else until the control unit is replaced. You've already tried everything else, right? If it doesn't work with a new control unit, then you can continue searching for solutions, but I would wait and see first...

@super7
Has the MSG software ever been updated to the latest version on your system? Check what version is installed after the update.

Does anyone happen to know what the latest software version is for the Fabia RS ASZ engine?

skywalker wrote:

Does anyone happen to know what the latest version is for the Fabia RS ASZ engine?

I am familiar with the 019NF SG 5839, which has an emergency braking system (LLT), but it corresponds to the 019LA SG 5405. I don't know if anything followed after that.
The 019NJ is already compatible with the BLT (EU4).

@skywalker

The device is still in its factory default settings.

I once talked to a mechanic about a software update while he was troubleshooting an issue a few weeks ago.

He stated that there was no need for action because there were no known software-related issues with ASZ control units, and the workshop would have been notified if such a problem existed.

I will contact him again when the new message arrives. Otherwise, I will discuss a software update and potential adjustments to the LLT threshold and improvements to the LLK with a tuner.