Audi A8 V8 TDI Injector Problems: AKF Engine

Hello everyone,

I own the vehicle mentioned above, and three weeks ago, I experienced an annoying malfunction with it, which was completely unexpected given that it's usually quite reliable.

After turning onto a road with right-of-way, I accelerated, and I felt a slight jolt, followed by a knocking sound coming from the engine compartment. A large amount of white smoke was coming from the exhaust, and it sometimes turned gray when I pressed the accelerator.

The sound was like hammering on an anvil with a thin towel acting as a sound dampener. It's coming from the right bank of cylinders.

The smoke plumes smell like diesel; it's obvious.

Off to the workshop it goes (a long story! you can read about it here:).

Diagnosis: Faulty fuel injector.

The nozzle was replaced, and the engine is running fine. However, during the test drive (which takes longer than expected because the smoke won't stop, presumably due to a lot of fuel in the exhaust), the loud knocking and smoking return.

Diagnosis: 3 more fuel injectors are defective.

All 4 nozzles have been replaced on the same manifold.

The engine is now running perfectly.

At the workshop, they told me that the cause of the injector failure was likely due to a lot of dirt and possibly some water in the diesel fuel. That would have damaged the injectors.
The diesel filter is supposedly completely blocked and probably hasn't been changed. That's not true; the filter was replaced 40,000 km ago!

I'll attach a photo of the nozzles and the open diesel filter.

Question:

Are there any other well-known cases of 'big' CR diesel engines with faulty fuel injectors?
War die Ursache bekannt? Tank leergefahren? Is there water in the tank?

Otherwise, the machine appears to be mechanically sound, with no issues with the camshaft, valves, rocker arms, or hydraulic lifters.

Thank you for any answers regarding the topic!

Stefan . wrote:

Are there any other known cases of the 'large' CR diesel engine with faulty fuel injectors? Was the cause known?

Was the tank completely empty? [url] Was there water in the tank? [/url]
I know that there were problems with debris in the first generation CR systems. My dad's car, at around 100,000 km, had the entire system replaced (under warranty) because it was emitting ESP debris.

I don't have the exact details in my mind right now, but if the injectors are failing one after another, I think a chip-throwing high-pressure pump could be the cause. Just out of curiosity, how many miles does yours have now? My dad's car is now at approximately 270,000 km (which is about 170,000 km with a new injection system) and hasn't had any significant further problems from the injection side. (Only the annoying search for the oil leaks cost us a lot of nerves. In the end, it was primarily the front crankshaft flange and secondarily the right valve cover gasket. See }/viewtopic.php?t=21355&highlight=akf}).

Unfortunately, I don't have any more information to answer your questions.

Regards,
Sure, here's the translation:

"Guste" is a German word that means "gust" or "gust of wind." It can also be used to describe a sudden burst of something, such as laughter or anger.

Hi,

Thank you very much for your answer!

The rolling aluminum box now has 164,000 kilometers on the odometer.

It's a 2002 model (May 2002) and was a special lease vehicle from Audi AG.

I had one injector replaced at 98,000 km, but it didn't make that much noise back then.
A second nozzle was replaced shortly after because the professional mechanics had damaged the high-pressure threads.

I find it interesting that all the ATMs at one particular bank were out of order, while the ATMs at another bank were working fine, even back then.

So far, he doesn't seem to be losing any oil, the valve covers are just slightly damp, and otherwise, there's not much to see, given how it's installed.

Regarding the shavings: Were any visible in the diesel filter? If the high-pressure pump is disintegrating, those shavings should theoretically be present throughout the entire system, including the return line.

The pre-lift pump was replaced once at 105,000 km because it was leaking (diesel was dripping out), and shortly after, it was replaced again because the drive shaft on the new one was broken.

Basically, just trouble with the car...

Stefan.

Stefan . wrote:

It's a 2002 model (May 2002, and it was a special lease vehicle from Audi AG).

My dad's Audi was also a factory vehicle and is two years older than yours (built in July 2000).

Stefan . wrote:

I find it interesting that all the nozzles at one particular gas station were out of order, while the nozzles at another gas station were working fine, even back then.

I can only explain it by assuming that the chips are only coming from one of the high-pressure nozzles. However, the fact that they only appear in one nozzle and not the other seems illogical to me.

Stefan . wrote:

So far, he doesn't seem to be losing any oil, the valve covers are minimally damp, otherwise there's not much to see, considering how it's assembled....

Do you notice, as soon as you have stains on your usual parking spot?

Stefan . wrote:

Regarding the shavings: were any visible in the diesel filter?

They should be present throughout the entire system via the return line if the high-pressure pump is disintegrating.}
Since my dad's car was still under warranty at the time, everything was diagnosed and fixed by Audi. Therefore, I can't comment on any shavings or other debris.