AKF Failure: Cylinder Missing After BAB Run.

Hello!

I've just spent some time reading through this forum, and I haven't found a solution to my problem here.

Okay, here's a question for the experts:

I have an A6 with an AKE engine. It has 160,000 km on it. It runs like a dream. Actually, so far, I haven't had any problems.

However, for the past six months, he has been experiencing the following problem:

You can drive the car at full throttle for about an hour without any problems (if you want), but as soon as you take your foot off the gas (when it's really hot) and then try to accelerate again, the whole car vibrates, and several cylinders (I estimate three) stop working.

'There are no entries in the error memory. The injectors are new because the error code 'Needle position sensor short circuit to positive' was previously stored in the error memory. This error can now be cleared. However, the problem persists.'

The air mass sensor is also new.

I'm now going to check the pump. But I don't really think it's a mechanical defect. I suspect it's more likely to be a problem with the pump control unit.

Has anyone ever experienced this problem before?

Does anyone have spare parts for a pump like this?

Regards,

Knubbi.

...does anyone really have any ideas???


Has anyone ever replaced the fuel pump control module?

My Audi dealer says: 'Replace the pump.' (approximately €1900 for the exchange).

I checked the power consumption of the electric fuel pump again yesterday, just to be sure. It's fine too.

What's also noticeable is that when the hot engine idles for a long time, the adaptation values for the idle speed control of the left cylinder bank go down to -2 to -2.5 mg/H. The cylinders on the right bank are around 0. However, the engine runs smoothly.

I'm really at a loss.

Hi,

To my knowledge, the VP 44 only has one solenoid valve that controls the injection process, and that should only have a driver amplifier in the electronics.
When deactivating individual cylinders, I consider an electronic problem with the ESP to be unlikely.
Perhaps something is getting too hot, causing steam bubbles to form in the fuel?
Or maybe somehow air is being sucked into the ESP system.

Best regards, Rainer.

...ah, at least some information.

'When air is being sucked in, there must be a leak somewhere. But I can't find it.'

Hi Knubbi,

Air can also be drawn in through even the smallest damage to porous seals, which are still too small to allow diesel to pass through. Introducing air into the system would certainly be a possible solution. However, I think the formation of steam bubbles, as Rainer mentioned, is even more likely. Have you rerouted the diesel lines in any way? Did you install a new cover? Even if you think it's unlikely, I once had a 60 horsepower Polo with an AEX engine, and it never gave me any problems. The only problem I had was once when I drove from Olpe (Sauerland) to Flensburg around 2 a.m. Because everything was clear, I drove almost exclusively at full throttle the entire time. When I got to Flensburg, it wouldn't start at the first traffic light, and I thought the problem was behind me. But when I opened the hood, there was so much heat under there that I hoped it was just that the fuel had gotten too hot, as the supply line ran very close to the engine, shielded from the wind. I waited half an hour, and everything was fine again.
Back then it was the height of summer... I'm not sure if that would happen with the current temperatures.

Okay, try searching in that direction.

The car is completely standard.

I'll still take the engine cover off later and see if I notice anything.

Okay, I'll also use the VAG tester later to check the fuel temperature while driving on the highway.

However, it doesn't seem to be a general problem, otherwise there would be something about it in the ELSA documentation.

...now I know a little more:

I just drove 180 km on the highway using VAG Com, and the error didn't occur!

(The fuel temperature gradually settles around 50°C when driving at high speed, although the VAG Com software labels the corresponding channel as 'fuel temperature - ambient temperature.' This would suggest that the actual temperature was 62°C.)

The only difference from usual was that the tank was completely full.

It seems like there's a fuel supply problem. I suspect it's the suction pump in the tank, which pumps fuel from one section of the tank to the other. (I forgot to mention that it's a Quattro).

Has anyone ever had problems with this pump?

That's indeed a very plausible explanation. Unfortunately, I don't have Quattro or 4motion. However, I think you can rule out the problem yourself if you remove the rear seat (or, in the case of a station wagon, the covers near the fuel tank access in the trunk) to locate the fuel pump and check if it's being powered (using a multimeter) and then doesn't work... otherwise, I'm also at a loss!

Yes, I will do that as soon as the tank is empty.

'Still, thank you for contributing your ideas.'

As soon as I know if that was the problem, I will let you know.

Best regards, Knubbi.

P.S.: Happy Easter.

Regarding the V6 engine, I believe there was once an issue with the oil cooler lines (rubber hoses).
Please search the error database; there might be information about it there.

Best regards, Rainer.