Performance loss and emergency shutdown in ARL TDI

Hello to all screw experts,


First, please don't judge me if I describe my engine problem in a clumsy way, but I'm not very familiar with the technical details of engines. Hoping you can at least help me a little.

Okay, here's the translation:

Short overview of the basic data: Drive a Skoda Fabia (original). KBST: ATD) converted to ARL with a 6-speed gearbox and all attachments.
But I also installed the motor's control unit. However, the software was completely taken over by ARL. Additionally, an OBD tuning was performed to achieve 180 PS and 400 NM.

Since the renovation, I have driven approximately 5000 km, and everything has gone smoothly and without any problems.

One day, when I gave my engine a real workout for a while, I noticed a strange hissing sound coming from the engine compartment. I initially thought it was the connection between the turbo, intercooler, and EGR valve, but everything is sealed! Ölsiff is also not yet fully understood.
The problem has been getting worse (with increasing noise + performance loss + smoking).
Under partial load, the engine operates normally, but only under full throttle does my control unit switch to limp mode after approximately 4 seconds... After briefly turning off and starting the engine, everything seems to work again initially.
So, I went to the workshop and read out the error codes...


This resulted in the following: +Gas pedal position (due to tuning???)
+Suction Air Temperature
+Engine Temperature (due to tuning???)
+System startup lock
+Brake booster switch pressure (deactivated AGR?)

Furthermore, a deviation of the LMM (0.5-0.6V too high) was already detected while the vehicle was stationary.
Checks of the turbocharger (control of the vacuum system, VTG, and pressure housing) revealed no errors. What many workshops noticed was the excessively loud noise from the pressure housing when purging. But the phenomenon has been present since the beginning. (I suspect it's due to an excessively high build-up of boost pressure???)

VAG - Com is unfortunately not available to me.



Does anyone perhaps have the actual - target data for a 180PS version of the 150PS TDI?

Our theories point towards faulty software in the engine control unit OR some kind of sensor malfunction.

I hope you can understand my description and perhaps offer some diagnostic suggestions. The entire debugging process has now been going on for almost 2 months, and I'm starting to get really fed up



Thank you in advance for your efforts....



Best regards
Martin

Hi

Quote:

Blow-off

is not present in this engine; the boost pressure is normally regulated.
For me, the errors seem more likely to be caused by electrical problems, such as water in the cable harness or control unit.

Without wanting to promote anything: without a diagnostic system, you won't get far here. "The desired and actual values can be read directly from the engine control unit, provided that the tuner hasn't tampered with it."
By the way, temperature sensors often fail, so it's a good idea to check the values in the engine control unit for plausibility.

KAT/Exhaust is ok? If it doesn't allow anything to pass through, it can sometimes make a hissing sound and the engine can overheat...

Hello, Rainer

Will it be reduced?

So, the sound is similar to that of a truck's air pressure release valve. (When the compressor tank is full.) It makes a really loud bang. It can also be compared to the sound of a pop-off valve from a gasoline engine...


Hmm, if the tuner didn't cheat... I think he did. This seems to be the conclusion. I have an appointment with him on Thursday. Let's see what comes out.





Best regards, Martin

Quote:

So, the sound is similar to that of a truck's air pressure release valve. (When the compressor tank is full.) It makes a really loud bang. icon_question.gif It can also be compared to the sound of a pop-off valve from a gasoline engine...

Either a pointless "show-off" pop-off has been installed (-> remove the junk) or there is a fundamental problem (leak in the intake air passage, blockage in the exhaust system).

Hello, Rainer

So, I definitely won't be doing a grand, public performance. Is the original printed cartridge that is installed. (I didn't know that there were such useless things )

Exhaust blockage... The system was only manufactured 1 month ago. Stainless steel complete system. It could be my catalytic converter that is blocked... I need to have that checked, thanks for the tip.




Best regards, Martin

Hello,
Finally, a like-minded person who also drives through the area with an ARL (local public transport) conversion.
I've also occasionally experienced similar issues, which are familiar to me.
First, I completely agree with Rainer. You need VAG Comm or similar diagnostic software, or alternatively, go to a VW dealership and have them print out a copy of the error memory. The sudden, strong hissing that you're describing, in my opinion, is coming from a leak in the boost system on the pressure side. It could just be a small crack that only opens at high pressure, which is then responsible for a sudden pressure release due to the leak. This would also explain your sudden choking and loss of power/limp mode. Please carefully check the hoses on the LLK. My right-hand had a small crack directly under the metal connection on the top side, which exactly caused your problem. A more involved method is using a compressor, but it's very informative. Seal the hose before the turbo (with a rubber stopper), and attach a rubber hose (bicycle inner tube with valve) at the top of the intake pipe and secure it with a hose clamp. Then, apply approximately 1.5-2 bar of pressure with the compressor. If the system cannot maintain this pressure, you have a leak somewhere along the way, or, in the worst case, within the LLK (Long-Term Coolant).
You will need to obtain the diagnostic software in order to be able to help you further.

I can only confirm this.

Take a close look at the charging hoses.
I had this problem once too. In the lower
Normal speed and then with increasing
High RPM results in hissing and soot.

It was the intercooler hose from the turbo.
to the air-to-water heat exchanger. Has a direct connection at the connection point.
Crack (approx. 3cm) I also got when the 2nd one.
looked.

Yes, thank you for the tips!

I'll go to my workshop tomorrow and bring a bicycle inner tube... Then I'll go through each pipe individually. If it's the LLK (likely a leak), I'll have to replace it, which will be expensive. I've often had problems with the hose directly behind the turbo that leads to the intercooler...

I really hope I can find something cheap and unnecessary...
Post again once I've fixed the problem.

Thanks for the generous tips.



Hello

Marv

Marv wrote:

Drive a Skoda Fabia (original) KBST: ATD) converted to ARL with a 6-speed gearbox and all attachments. . .

Hi,

Just one question on the side:

What LLM are you driving with in the Fabia?
I'm actually struggling to figure out how to get a nice, large LK (presumably a specific car model) into my sister model, the Polo (9N).

Regarding your problem, I also suspect a leak somewhere in the "suction" pipe area, or
possibly a "misalignment" of the fuel pump and AGR (Exhaust Gas Recirculation) control -> 2. Posting in /viewtopic.php?t=10246

@ Ulf


I'm using the large LLK from ARL. It was a real challenge to get it working, but it did... However, the front mask had to be completely reworked. Furthermore, we installed the LLK at an angle. Otherwise, it wouldn't have fit...

I have the complete renovation documented as an image!

But I'm just wondering why you want to disable the large LLM. When it comes to performance gains, it's all for naught...


Greetings, Marv

Marv wrote:

I have the complete renovation documented as a photo album!!!

Wow, that's great! Could I have that (PM or email to ubeck13@aol.com)?

Quote:

But I'm just wondering why you want to install the large LLM? When it comes to performance gains, it doesn't really matter...

Not directly, but it improves the thermal health of my engine. I have an engine with approximately 160 horsepower, but I'm still using the small ASZ-SMIC -> LLT system, which operates up to 50K over AT (atmospheric pressure), resulting in temperatures of 80°C or more in the high summer, even with the cooling air intake fully open .

Have you ever logged your LLT (Low Level Temperature) in the Pmax range (and subtracted the ambient temperature)?

Yes, I'd be happy to send them over... No problem.


So, I'm using a WAES injection (water/methanol) system to reduce the intake air temperature.
Essentially, the engine is tricked into believing it has a massive amount of torque, which significantly impacts its performance. Maybe I have an intake temperature of 40°C even in the height of summer!!!
If you want more information about this: www.Turbotuning.net (This is not an advertisement )
By the way, I also made a small video.
While it's only with a smartphone camera, you can really see the performance of the car. If you want, I'll send it to you...



Greetings, Marv

Marv wrote:

Yes, I'd be happy to send them over... no problem.

Thank you

Quote:

By the way, I also made a small video. While it's only with a smartphone camera, you can really see the performance of the car. If you want, I can send it to you...

No, thank you, I don't need it. ... For my performance, a reasonable LLK is sufficient.

Hello,


I just checked the pipe system in my workshop.
The connecting pipe from the LLK (Low-Pressure Turbocharger) to upwards towards the AGR (Exhaust Gas Recirculation) is completely leaking. There is nothing visible. No oil, no cracks, etc. But it starts to blow out at 0.5 bar.

Many thanks to you for the idea of HOW to check everything. Without a bicycle tire and a pump, we would never have found it!



Greetings from Marv!

Marv wrote:

The connecting pipe from the LLK (low-pressure air system) to the AGR (air-gas recirculation) is completely leaking. There is nothing visible. No oil, no cracks, etc. But it starts to blow out at 0.5 bar.

It's great that you found the problem before the compressor failed.
Idiot, that the instant location via oil sensor didn't work

Is your entire other "suction" pipe area also dry?
Or how far does an oil film extend along the inner sides of the pipes?

Hi,


@ulf



Okay, so, the inner pipe is already coated with oil. However, since there is also dirt from the installation on the outside, it doesn't show. What's strange is that the thermal joint behind the sensor (pressure sensor? I'm not sure) is sealed. Behind that is a mounting piece. Apparently, the air is finding its way through the seam. Even the workshop was very surprised.


I'm really impressed with these great Clip Fix connections... This is the final piece!
Do you happen to know a company that offers adapter flanges for the VW system?

I've already contacted Grundler, but their customer service isn't meeting my expectations.
They don't respond to phone calls, nor do they respond to email requests...

Would like to further revise the loading air track during the winter break...





Best regards, Marv