Sharan CFFB regeneriert alle 30km | Posts 16+

Blackfrosch wrote:

Quote: Allerdings hilft auch die Variante mit 2 tatsächlichen physikalischen Anschlüssen am DPF bei dem Fehler nichts, da das Motorsteuergerät nur den Differenzdruck als Signal bekommt, nicht die absolute Höhe der beiden Drucksensoren. Natürlich hilft das: Es geht ja um den Druckabfall überm DPF und der wird immer korrekt erfasst mit 2 Messtellen. ...

"No, I don't think that helps. As far as I know, the differential pressure sensor doesn't transmit Pressure 1 and Pressure 2 to the engine control unit, but rather only the difference between them."
You can certainly try to convince me otherwise, but those two pressures should appear somewhere within the measurement blocks.

This means that a differential pressure sensor connected before and after the DPF doesn't actually measure any differential pressure across the DPF if you put a potato in the exhaust pipe.
That's also correct.

The "economy version" with a connection between the turbocharger and the DPF, and the reference "air pressure" (the second connection from the differential pressure sensor goes to the open air), detects the potato in the exhaust system; it doesn't measure the differential pressure across the DPF but rather the entire remaining exhaust system. And the pressure drop across the "remaining" exhaust system is modeled in the engine control unit, which allows for a relatively accurate estimation of the pressure difference across the DPF.

chli1976 wrote:

The SCR catalyst was clogged,

, Hello, what did you do about the blocked catalytic converter? Did it have to be replaced? I'm having the same problem; the measured soot mass is increasing very quickly, regardless of whether gas is given or the engine is running in coasting mode without gas. The pressure at the differential pressure sensor increases to 600 hPa during acceleration.
Best regards, Jens.

I removed it and took the function out of the software, but you will lose the operating permit.

chli1976 wrote:

I cleared it out and removed the function from the software, but you will lose the operating permit

.

If you want to continue operating legally, you can also purchase refurbished Selective Catalytic Reduction (SCR) catalysts as replacements online. They are typically about half the price of new ones.
I had one of these installed 30,000 km ago, and it's still running without any problems.

Regards,
Ralf.

Thank you for the responses. I've already looked into it, and it seems that the SCR catalytic converter is a rare part for the Audi Q3. I'll see if those from other models with a 2-liter diesel engine might be compatible.
Once I've looked into this matter further, I will provide feedback. I wish everyone a happy start to the new year.

Best regards, Jens.

Hello,
Here's another update on my problem with frequent regenerations.
It wasn't the SCR catalytic converter that was causing the problem, but directly the DPF (Diesel Particulate Filter). To check, the exhaust pipe behind the DPF was disconnected. However, the high pressure difference remained. Then, a nearly new replacement DPF (with approximately 4,000 km of mileage) was purchased and installed. It was an incredibly complex job that took about 10 hours with two people. This is for an Audi Q3 Quattro with a 2-liter CR TDI engine producing 110 kW.
The ash content was then adjusted to 1 gram, and now it runs for approximately 400 kilometers before requiring regeneration. During this period, the measured ash content decreases down to -4 grams during the regeneration process.
Now, the only question that remains is why the old DPF was already so heavily clogged after only 130,000 kilometers.

I hope I can help with that.

Jens Grundmann.

Thank you for the feedback! Inappropriate engine oils that could produce more ash during combustion might be a cause.

Therefore, always use an oil that meets the specified standard.

Hello,
"No problem, someone who's having trouble always looks forward to a final solution. I don't find the car's diagnostic system sufficient for this particular issue."
Regarding oil, I have always used the recommended Liqui Moly 5W30 longlife oil and never experienced significant consumption. I always changed the oil at intervals of 15,000 km. However, I always added an additive to the fuel tank that is supposed to lower the combustion temperature of soot to 400 degrees Celsius. I believe the product is called Eolys and is used by PSA in some models.
Perhaps one shouldn't do something like that .

Best regards, Jens.

No, you shouldn't do that. The system is designed in such a way that it can burn off the produced gas. Since this gas ignites at a certain temperature and oxygen concentration, everything should be fine. However, if your substance accelerates this process, it could lead to excessively high temperatures locally, causing the material to sinter together.

If you still have the DPF: Use an endoscope on the inlet side, or use a flexible tool to open it up. I bet you'll find completely blocked channels.

Generally speaking: To all those who read this: Only the fuel specified for a particular vehicle should be put in its tank. When it comes to engine oil, you should also adhere to the standards and can choose between low viscosity (LL) and "normal" grades according to your preference.

If you don't exclusively drive short or very short distances...

Specifically: Because your issue is unusual in this context, this additional information is certainly a reason for concern. However, there might be another underlying cause (e.g., excessive oil consumption due to a faulty component, a defective fuel injector...). Investigate the matter further; otherwise, you'll likely find yourself back in the same situation soon.
The Russmass value being below 0 is likely due to the loading factor you specified being too low (1). Is this a DPF from "eBay"? They always seem to have only been driven for 4,000 km, which seems rather suspicious.
"Especially with all-wheel drive vehicles that have a transversely mounted engine, any work between the turbocharger and the exhaust system is simply awkward. Therefore, find all the underlying causes, otherwise you'll be doing this again soon."

Thank you for your assessment; there might be something to it. The engine hasn't been consuming excessive amounts of oil, and the injectors are still within normal parameters according to the test results.
ich werde das weiter beobachten und berichten wenn es was Neues gibt. Leider find ich beim VCDS nicht die Funktion zum anlernen der Differenzdruckgeber, da bin ich scheinbar zu blöd.

Best regards, Jens.