Fabia RS: Lacking Power? Performance Review

Hello, I've been following the Diesel Mechanics Forum for a while now, and especially the threads about vehicles with underperforming ASZ engines.

"I'm experiencing similar issues with my RS (10/03, long gearbox, no chip, 75,000 km). It generally runs fine, but it just doesn't feel right. Especially at higher RPMs, the power is lacking, and I'm not reaching the top speed."
"There's no soot at high RPMs, but it tends to produce black smoke, especially when shifting into a higher gear around 2000 rpm. My gut feeling is that it might be lacking boost pressure, or the variable geometry turbocharger (VTG) could be sticking."

I want to get to the bottom of this issue, so I bought an original interface with the latest VAG-COM software, which should arrive within the next few days.

Before I do anything wrong, I'd like to ask how best to proceed with the test run, especially which measurement data should be logged simultaneously. Perhaps someone can give me some brief, structured advice!

In previous posts, I've seen the following combinations mentioned: 3-8-11 and 1-7-8.

What is meaningful?

samoht wrote:

Before I do anything wrong, I would like to ask how best to proceed with the measurement run, especially which Measurement Data Blocks (MWBs) should be logged simultaneously? Perhaps someone can give me some brief, structured help! In previous posts: I have read the following combinations: 3-8-11 and 1-7-8.

Hi,

First, check the MSG screen to see what software number (SGxxxx) is displayed there.
At 5266, you have the version that drastically reduces performance at high LLT (Load Limit Threshold).
Depending on the external contamination of the lubricating oil, this can even happen in winter after just a few seconds of full throttle and high engine speeds.
To specifically monitor the engine's performance, it would be helpful to record data points 1, 7, and 8 while driving in 4th gear at full throttle, starting around 2500 rpm and ideally reaching up to approximately 4300 rpm.

For SG 5405, the LLT (Low Load Torque) is hardly a relevant factor; I would rather start with values of 8 and 10. Often, parameters like air mass, actual boost pressure, and limitations are sufficient to determine where further investigation is needed.

Approximately how fast does the vehicle travel on a flat surface with no wind?
Tire size? Roof rack or giant spoiler?

Quote:

It particularly tends to emit black puffs of smoke when shifting into a higher gear at engine speeds around 2000 rpm.

Have you ever checked the intercooler piping for leaks (and looked for any external oil seepage)?

Hello Ulf, thank you for your quick reply. I found some oil leaking at a connection point in the intercooler system.
After that, I replaced the rubber seals. Unfortunately, it didn't make a difference; it still leaks slightly, and the performance hasn't improved as a result.
Both the Volkswagen and Škoda workshops I trust said that "this is normal" and that they would always leak a little, but that it wouldn't cause any loss of performance.

My argument that the turbocharger might need to spin faster to compensate for potential pressure losses, and that this could lead to premature wear and tear, was not really well-received.

The Fabia comes with 17-inch 205 tires in the summer and can reach approximately 195 km/h in 5th gear, according to the speedometer (which is quite accurate compared to the actual speed measured by GPS).

"Somehow, the car lacks punch throughout the entire rev range (even with 15-inch winter tires!). It simply doesn't feel as responsive and, in my opinion, pulls uphill somewhat reluctantly. Around 2000 rpm, where you would expect a noticeable surge of power, the engine characteristics are surprisingly balanced and quite uncharacteristic for a diesel. I'm not sure to what extent the long gear ratio plays a role in this."

Hi,
I also think you should keep looking. A well-maintained 74 kW TDI estate can also reach speeds of 195 km/h. However, the standard (5-speed) transmission has a different gear ratio.
It's amazing that the GPS and speedometer are matching. I know of a case where the speedometer was off by 10%.
Here are some posts about the oil leak and the LL track.
haithamina

'...The speedometers on TDI cars, calibrated up to 260 km/h, are quite accurately scaled.'
However, even in the Ibiza 6L, I have a speedometer overreading of 3%.

Darius.

With the 17-inch wheels, there might be a difference of about 3 km/h (195 GPS vs. 198 speedometer). With the 15-inch winter tires, the difference is significantly larger (10-15 km/h?). Apparently, they have a smaller circumference, or rather, the 17-inch wheels have a slightly larger circumference than the standard 16-inch wheels.

I hope I can finish the logs by Saturday. Hopefully, everything will work correctly with VAG-Com; I'm a beginner in this field .

I will also post my MST number and an Autoscan as soon as possible.

Thank you for your comments.

samoht wrote:

Somehow, the car lacks power across the entire rev range (even with 15" winter tires!). It simply isn't as responsive and, in my opinion, feels somewhat reluctant to accelerate. Especially around 2000 rpm, where a "kick" should be felt, the engine characteristics are almost unusually balanced and quite un-diesel-like.

With which cars (model, engine type) are you comparing your RS to, in order to arrive at these statements?

If the 205 tires are indeed significantly larger than the WR tires, then with the longer gearing, the 5th gear will definitely become the top speed gear (standard: 200 km/h in reality at 4000 rpm)!
By the way, I'm surprised you got a listing for such large flip-flops... what exactly is the size?

Hi Ulf, the size is 205/40 R17. That's a common size for the Fabia.
Let's hope the delivery service brings the VAG-Com interface today!

samoht wrote:

Hello Ulf, they are 205/40 R 17. That is a common size for the Fabia. With the 17" wheels, there might be a difference of 3 km/h (195 GPS to 198 speedometer). With the 15" winter tires, the difference is significantly larger (10-15 km/h?). Apparently, they have a smaller circumference, or rather, the 17" wheels have a slightly larger circumference than the standard 16" wheels.

Well...

The size differences between the 205/40 R17 and 185/55 R15 tire sizes (which are among the smallest winter tire sizes available for the Polo 9N / Ibiza 6L and Fabia) are only about 2%.
205/45 R16 tires are pretty much in the middle [of a range].

Within the range of approximately 200 km/h, the actual speed (with the same engine RPM and gear) would likely only vary by about 4 km/h between the 205s and the 185s. Therefore, for example, a car with 205 tires might have a theoretical speed advantage of 7 km/h compared to one with 185 tires, whereas it would be only 3 km/h with the 205s.

If you then add in slight speedometer reading errors and/or tolerances in the rolling circumference (up to 4% is allowed, which equates to 8 km/h around a speed of 200 km/h), discrepancies of over 10 km/h between different tire types can easily occur.

So, the Fabia RS, with its standard output of 130 horsepower, has a stated top speed of 206 km/h.
Die erreicht er in der Regel ganz locker und die meisten Fabia RS gehen noch weit über 210km/h. Bei deinem RS ist allerdings das Getriebe verlängert worden. Die Frage ist nun ob nur der 6. Gang geändert wurde oder auch noch der 5. GaSure, here is the translation of the text from German to English:

"ng?"
If it's struggling to get going properly even in 5th gear, you could suspect a problem. If there are no symptoms typical of a heavy load VTG (Variable Turbine Geometry) system in the lower gears, and it doesn't go into limp mode at higher RPMs, I would lean towards a Mass Air Flow sensor (MAF) issue. However, a more precise diagnosis can only be made after a diagnostic run using VAG-COM.

The original tires on the Fabia RS are 205/45 R 16 83W. I don't think the tires have any influence on the problem. In any case, they don't cause a loss of more than 10 km/h in speed.

CU, thanks.

No, the transmission has not been modified.

The first Fabia RS models had a long gearbox, where the 6th gear essentially functions as an "ECO" gear. However, due to the excessively long gearing of the 6th gear, the top speed is only reached in 5th gear. Nevertheless, this allows for significant fuel savings.

Die neueren Fabia RS haben das kurze 6-Gang Getriebe verbaut, sie erreichen die Vmax im 6. Okay.

The VAG-COM has just arrived; I'll probably be doing the test drives on Saturday.
I will post my version of the MSG tonight; it's a quick process.

Best regards.

@ulf: I might be mistaken about the different deviations, as I'm just guessing based on memory. Right now, I have 185/55R15 winter tires installed. I'll try it again to see how big the deviation is with those.

Okay, so it seems they've come to the realization that an RS doesn't necessarily have to be a sporty car and also a diesel fuel-efficiency champion.

Bei wie viel rpm macht er denn im 5. Is your gait unsteady?

CU, thanks.

Just now, I used VAG-Com for the first time to access some data.

Unfortunately, the software version of the MSG is 5266. I'll probably have it updated during my next inspection.

The diagnostic scan revealed an error:

Quote:

1 Fault Found: 18263 - Powertrain Data Bus: Software Version Monitoring. P1855 - 35-10 - - - Intermittent Readiness: 0 0 0 0 0

And this issue, even though it occurs sporadically, cannot be resolved?
My car dealership had previously pointed out this issue to me, but they didn't consider it particularly significant. Also, when I inquired about it, Sebastian also classified the error as non-critical.

Besides that, I noticed two more things during the inspection in the garage, following the instructions in the technical article:

Quote:

-> In MWB 6, both brake switch bits should change state simultaneously and indicate that the clutch is being engaged.

My display is changing from 0 0 0 to 1 0 0?!

Quote:

-> In MWB 10, the charging pressure and external pressure should be approximately equal within 20 mbar when the engine is stationary.

OK.

Quote:

-> In MWB 7, the temperatures should be within +/- 3°C of each other when the engine is cooled down (!), and they should be plausible during operation.

It's showing 15°C on my device, even though the outside temperature is only 4°C?! Does a motor cool down after just 2 hours? Maybe not. I'll check it again next weekend.

Otherwise, I have auto-locking and auto-unlocking enabled. It worked perfectly right away.

This weekend, there are logging trips available. Now, let's finish exploring Germany and Switzerland.

samoht wrote:

Unfortunately, the software version of the MSG is 5266. I'll probably have an update installed during my next inspection.

Okay, have fun trying to get the update: I suspect it won't be easy through Skoda, because the explanation "Software version 5405 doesn't open the valve as much at high load levels" will probably just raise eyebrows there.
As a response, you'll likely hear something like: "Where did this information come from?"
"From a diesel mechanic."
"Oh, from the internet? There's so much nonsense on there..."

You probably won't have as many problems with a chip tuner. Our host lives not too far from Aachen and can certainly help you.
But then we'll miss the "comedy" at Skoda...

However, the performance reduction caused by LLT may not be the cause of your problem.
First, create a log with the format "1-7-8" because you can clearly see it in that format.

Quote:

-> In MWB 6, both brake switch bits should change state simultaneously and indicate that the clutch is being engaged. In my case, the display changes from 0 0 0 to 1 0 0 ?!

... when coupling. When braking, the last two components should click into place.

Quote:

Does a motor cool down after just 2 hours?

No, more like after 6 hours or even longer.

ulf wrote:

However, the performance reduction caused by LLT may not be the cause of your problem. First, create a log with the format "1-7-8" because you can clearly see it in that format.

I completely agree. He isn't chipped, so he shouldn't "technically" have any problems with the low-temperature limit.

I'm driving the car on Friday.

Thank you for your help already.

samoht wrote:

He is not chipped and therefore should "actually" not have any problems with the traffic light system.

... as long as the cooling air path is clear through the SMIC.

Experience shows that this is often only a temporary condition in new cars. As soon as the cooling system starts to become clogged, the LLT (Low Temperature Limit) increases accordingly, and the software 5266 consequently responds with increasing power reduction above certain thresholds, in order to keep combustion chamber and exhaust temperatures within an acceptable range.

[Speculation ON]
The search for the actual cause (namely, the dirty SMIC) likely overwhelmed so many dealers and workshops that, under the pressure of countless "unsolvable" customer complaints regarding new cars, software version 5405 was soon used instead of making a design change to the front bumper to improve cooling airflow to the SMIC.
[Speculation OFF]

The 5405 allows for higher LLT (Low Load Temperature) values, and consequently, more critical combustion chamber and exhaust gas temperatures, before the fuel supply is shut off, which is done significantly more gently compared to the 5266.
However, if the SMIC (Surface Mount Integrated Circuit) is kept reasonably verschandeln on the outside, one can freely stress the RS (likely referring to a specific component or system) with the 5266 (presumably a testing parameter or device) up to an ambient temperature of approximately 25°C without noticing any performance degradation.
By further optimizing the airflow (removing the misting system, fully opening the spoiler vents, etc.), it's possible to raise the threshold for noticeable performance loss to around 35°C, allowing you to drive with high performance at any time during even the hottest European summers, despite software version 5266.

My sympathy definitely goes to the software 5266, which prioritizes the protection of the material from critical temperatures over the driver's desire for full power at any time, thereby educating him to pay attention to an optimally effective lubricant - provided he understands the background .

It's not meant to be taken personally.
Let's see what your logs tell us...