A6 4F 3.0 TDI - Exhaust, Diesel Particulate Filter...

Hello everyone,

I'm currently experiencing a problem with an Audi A6 Avant 3.0 TDI from 2006, equipped with a BMK engine. A *** chip tuning system has been installed in the car, starting from the "factory" setting.

The car's exhaust smells quite strong (sweetish), and in some cases, the car is emitting a lot of smoke. The interior sometimes smells quite bad.


I suspect, among other things, that the diesel particulate filter (DPF) is clogged, as it has a relatively high load level. Here's a translation:

"I'll just add some information about the DPF here."

Address 01: Engine Control Module (4F0 910 401 N)
15:13:46

11.8 mbar differential pressure, particulate filter.
0.75 Oil ash volume.
14.1 Loading weight - mass value.
12.3 Loading capacity - mass value.
280 km - Distance since last regeneration.

I will therefore have the filter cleaned or install a replacement filter.

Regarding the injectors, I'd like to mention that the car had its injectors (diesel technology...) refurbished at 52,000 km. I have attached the values as a photo, and the MWB 77 value seems suspicious to me.

Steering Calibration Point 1: 0.0ms
Steering Calibration Point 2: -14.0ms
Steering Calibration Point 2: -6.0ms

Is it normal for values to be at that level with revised injectors after a certain amount of mileage?

It would be great if you could give me some tips.

Hello.


Regarding the values of the injectors:

After 52,000 km, this is not normal, because negative values indicate wear, which means a leak. Unfortunately, it's not just that one injector that's suspected to be faulty.
At the lower pressure settings, it should ideally exhibit slight idle fluctuations due to post-injection. That explains the smell.
Which parts were installed? The BMK (likely referring to a specific engine or component) was very susceptible to issues, which is why the injectors were changed starting in model year '07. The ones from ASB, with 233 horsepower, would be more stable.

The exhaust smell is a common issue with the first-generation CR-V6 diesel engines. The issue is usually caused by a worn-out housing for the AGR valve conversion.
Remove the engine cover. Just to the left of the turbocharger, there's a small black vacuum canister that controls the valve.
The valve housing directs exhaust gases and coolant, but exhaust gases escape from the defective bearing of the shaft.
Usually, everything around it is quite sooty; just take a deep breath near it after a cold start, and you'll immediately smell it .

Unfortunately, the storage compartment cannot be swapped out because the flap inside is welded to the shaft, making it impossible to disassemble.
The new one is 059 131 063 D and costs approximately 130€.

Regards, Mpire.

Hello Mpire,
Thank you for your feedback and information... I'll need to take a look at the AGR cooler tomorrow in daylight. It makes sense, anyway.

Regarding the injectors, I thought about it, but I didn't expect the injectors to "wear out" so quickly again.
According to the wear limits (first value -45, second value -15), they don't need to be replaced yet, right?
What could have caused the premature wear? They were installed last December and haven't been driven for that much, only 50,000 km. It probably doesn't speak very highly of the quality...

Perhaps someone can give me some more information about the log values for Turbo and Mass Air Flow Sensor (MAF).

"Thank you very much..."
Charmilles.

PS: I'm probably not doing well with the particulate filter either; the ash content is very high at 0.75. A forced regeneration would probably no longer be advisable.

charmilles wrote:

PS: I'm probably not doing well with the particulate filter either; the ash content is very high at 0.75. A forced regeneration would probably not be advisable anymore.

Unfortunately, the ash cannot be regenerated, only the soot, which essentially represents the accumulated residue. That's actually quite normal with 14% after 280km; I get something similar with a bit more short-distance driving.
And the 280 km since the last regeneration also suggest that it is still operating normally and regenerating regularly. It would mean that it would self-ignite again after approximately 500 km.

Regarding my experiences with 2.7/3.0 TDI engines and the "actual" ash content (which may not correspond to the calculated value), I can say that the 6-cylinder common-rail (CR) engines tend to have significantly less ash buildup than what is calculated. It can be relatively well identified by the measured differential pressure under load.

...and the two that were actually full also regenerated regularly, although with a significant amount of smoke coming from the back.

According to the Audi guidelines, the value at which the workshop should take action is 0.46.
According to the manual, no error message will be displayed if the ash content exceeds the specified limit, but an error message will be displayed if the soot load exceeds the limit, which is 30%. "The flash point is typically around 25% loading value for me."

Regards, Mpire.

Hello Mpire,
Thanks for your feedback and explanation. The DPF is probably going to fail eventually anyway. I'll get started on the work next weekend. It looks quite "dusty" around the enclosure.

What is the best way to replace the valve? Does the entire AGR cooler need to be removed, or can the work (e.g., swirl flaps, cover, EGR valve) be done while it's still installed?

Thank you for the information!

Best regards,
Charmilles.

PS: What do you think about the turbo and mass airflow sensor values? When I look at them, they don't seem quite right. The turbo has quite a few miles on it now, approximately 370,000 km.