Audi A4 TDI: Engine Limiting & Smoke Issue

I have a HUGE problem, and maybe you're my last hope!!
Besides faulty mass airflow sensors and oil vapor filters, my car has been reliable so far.
And now:
The following happened on a regular country road:
Loud clicking (which I believe is a nozzle), and the engine was barely responding to the throttle. When going downhill without using the accelerator, there was no noise! Only when idling and without being in gear did it click again, and there was blue smoke.
I immediately pulled over and turned off the engine. It smelled very strongly of...
unburned diesel fuel. I then restarted the engine, and the knocking sound disappeared.
Only the engine spins up to a maximum of 3000 RPM (very little power), and above that, it starts to smoke terribly blue. At idle and up to 2000 RPM, there is no difference from before.
The turbine typically starts at 1400 RPM and pulls normally.
It feels like the engine is struggling or choking at 3000 RPM. I managed to borrow a VAG-COM diagnostic tool from a friendly colleague for 20 minutes.
It said:
Control unit locked.
Intake manifold pressure differential.
Injection start (regulation difference).
At idle, it showed a spark advance of approximately 0 degrees, then 2 degrees, and so on.
I cleared the error codes.
'But the error regarding the injection timing cannot be cleared!'
Called the friendly Audi service center and they said the pump is almost certainly broken :=((
Perhaps you could give me some tips, although it's strange that the engine...
It runs normally at idle and under load, and develops almost normal torque.

PS: I don't have any oil in the coolant reservoir, and the VTG (Variable Turbine Geometry) is easy to move.

Hi,
I don't have a definitive tip for you, but here's the direction I would explore:
-For the sake of completeness, we should check the tightness of the turbocharger boost hoses, but it's probably not the cause due to the clicking noise.
-The valve timing, or the adjustment of both camshafts relative to the crankshaft.
-This is also related to the injection timing; I don't know the specific value, but it might be somewhere on this page (using the search function). If only the needle valve is affected and not the entire injector, that doesn't necessarily tell us much.
-The condition of the camshaft, rocker arms, and valves. The AFB is also prone to damage in this area.

Hi, you should check the timing belt (timing). Otherwise, with the AFB engine, I know about the problem with the camshafts and possibly defective fuel injectors.

Best regards,
Volker


PS: Unfortunately, you didn't mention where you're from. Otherwise, we could have taken a look.

I'm from South Tyrol, although I sometimes live in Kaufbeuren. I have a car today.
They should take it to the workshop and have them check what's wrong.
On the highway, the car reaches exactly 120 kilometers per hour, and no more or less.
and no smoke is visible up to 3000 RPM.
'The engine runs perfectly smoothly when idling. Yesterday, I checked the turbine again until midnight. I observed that the variable turbine geometry (VTG) fluctuates significantly up and down when it reaches 3000 RPM and starts producing blue smoke, accompanied by surging.'
I checked everything again for leaks (coolant, oil, etc.) and found nothing.
Let me know!

PS: Something feels off since I changed the filter.
It seems to be related to the oil vapor (or whatever it's called). I was told that the turbo had to be removed to fix it. Fingers crossed!

Fuel injection pump now definitely defective .
Could someone please give me a tip?
Repair, new, or...?
The Bosch dealer mentioned approximately €1400.00 for a new .
I think I'm going crazy.
I am grateful for any suggestions.
Greetings.

Hi,
You could try disconnecting the vacuum hose from the VTG valve and sealing it with a screw. This would keep the VTG valve fully open. While this might cause a significant turbo lag, it would eliminate any issues caused by excessive valve movement. Let's see what your engine says at high RPMs.
The pump cannot be repaired. It has a built-in control unit that is calibrated to the mechanics at the factory.

seabauer wrote:

The fuel injection pump is now, in fact, defective. Could someone please give me a tip? Repair, new, or...? The Bosch dealer mentioned approximately €1400.00 for a new . I think I'm going crazy. I am grateful for any suggestions. Greetings

eBay car dismantler - scrapyard. Or, you could have it repaired, because perhaps only the pump head is clogged. That part costs about 600 plus installation.

Hello Seabauer!

I'm also having a HUGE problem with my V6 TDI that I can't figure out. Even Audi and my VAG workshop are scratching their heads.

I also installed a new pump (as a precaution!), but it didn't work. So, I still have my original pump here. (see 'For Sale' section).

I can assure you, replacing the fuel pump isn't that difficult. If you want, you can take my fuel pump from the 180 HP engine (at a good price) and see if it works.

While my problem hasn't gone away, at least I've been able to help you. Sigh!

Regards,

Knubbi.

I'm still thinking about it and I've already complained to my dealer. This can't be right – the ESP failing after only 156,000 km (1400.00 € + labor + ...)? It's probably a joke. Putting aside the Audi brand for a moment, just as a regular consumer, this is unacceptable. I've always changed the filters every 15,000 km, I've never used biodiesel, no tuning, no messing around.
In addition to that, the two handlebars in the front need to be replaced, and the clutch is slipping terribly.

Are there any other 'AFB victims' in this forum?

I got a really weird feeling in that Bosch workshop. One guy said, 'VP44 and AFB, and *ggg*,' and the others all looked at me, and then one of them said, 'And tomorrow, it's the next one...'

Hi,

Just search for 'AFB' (using the search function).

/viewtopic.php?t=3687&highlight=afb
/viewtopic.php?t=1975&highlight=afb

Best regards, Rainer.

Not bad for an engine that was praised so much 4-5 years ago (and still is). I'll start thinking about alternatives, as I need the car for work and I'm tired of spending time in the workshop. Hopefully, a car like this is still something I can sell.

Hello,
Be glad that your AFB lasted so long. In my case, the full program was due at 134,000 km. It included camshafts, hydraulic lifters, rocker arms, injectors, a few idler pulleys, etc. The whole thing cost me about €2200 just for the parts. The biggest outrage is how Audi treats its customers. When I asked about warranty coverage, they almost laughed at me. Maybe we AFB/AKN drivers should get together and write a polite letter to Autobild.

Best regards,
Volker

The early AFB engines are probably the worst thing Audi has ever developed.
Volker32 has already listed the worst vulnerabilities.
In all forums, you can quickly find 'AFB users' who are dissatisfied.

It's somewhat comforting to some people that the newer V6 TDI engines (e.g., AKN) are supposedly less prone to problems.

In my opinion, the engines are far too noisy, both when cold and when warm. I also frequently read about highly questionable fuel consumption figures of around 11 liters. And the VP44 injection pump is also quite outdated by now.
It's certainly not a moment of glory, especially for the person who was practically the inventor of the TDI engine, although I remember how, in the beginning, Audi boasted in the press about having the 'first V6 TDI passenger car engine.'

The early AFB engines are probably the worst thing Audi has ever developed.
Volker32 has already listed the worst vulnerabilities.
In all forums, you can quickly find 'AFB users' who are dissatisfied.

It's somewhat comforting to some people that the newer V6 TDI engines (e.g., AKN) are supposedly less prone to problems.

In my opinion, the engines are far too noisy, both when cold and when warm. I also frequently read about highly questionable fuel consumption figures of around 11 liters. And the VP44 injection pump is also quite outdated by now.
Especially for the quasi-inventor of the TDI, it's not a moment of glory, although I remember how, at the beginning, Audi boasted in the press about the 'first V6 TDI passenger car.'


Hello!

Even though many people here criticize the AFB, I still want to defend it at least a little bit .
Mine now has 204,000 kilometers on it.
The first injectors and camshafts, rocker arms, etc. have been installed. This vehicle was manufactured in May 1998 and probably belongs to the 'older' AFB series.
Okay, it doesn't start as well in the cold compared to my other one in the Golf (1Z) with the TDI engine, and it's leaking a little oil (still too high crankcase pressure).
The fuel consumption for my V6 is anything but high! I drive it and get 6.8 - 7.8 liters per 100 kilometers, and that's not exactly with a light foot .

I hope it survives another 50,000 km, because then it will be sold *taps wood*.

Regards,

DENNIS

It's always the same story: one person drives their V6 engine to 300,000 km, while another person is already complaining before reaching 100,000 km. As for fuel consumption, I've always managed to stay within the range of 7-9 liters, which, in my opinion, is good considering the power output.
A replacement pump has been ordered (valued at €1250) and the old one will be taken back. Finally, the invoice will be issued. The refurbished pump will be installed in my vehicle, and my old pump will be repaired. Only the repair cost will be charged, not the entire pump, for a total of approximately €550.00. (THIS IS ONLY THROUGH THE BOSCH DEALER).
At VAG, prices start at €1,800, including installation and VAT (friendly).
Best regards, Helmuth.

It's always like that; one person drives their V6 engine to 300,000 km, while the other person is already complaining before reaching the 100,000 km mark. Regarding fuel consumption, I've always managed to stay around 7-9 liters, which, in my opinion, is good considering the power output.
A replacement pump has been ordered (valued at €1250) and the old one will be taken back. Finally, the invoice will be issued. The refurbished pump will be installed in my vehicle, and my old pump will be repaired. Only the repair cost will be charged, not the entire pump. The total cost will be approximately €550.00 (ONLY AVAILABLE THROUGH BOSCH).
At VAG, prices start at €1,800, including installation and VAT (friendly).
Greetings, Helmuth:-(.

Hello Helmuth,

I hope that the price is somehow documented in writing. Unfortunately, I've had bad experiences with Bosch service in the past. In my case, the alternator (charging control went out briefly after starting and then came back on). I assumed that an alternator from Bosch would be better handled at a Bosch service center than at Audi. So, I went to a Bosch service center nearby in Wiesbaden. They accepted the job to inspect, repair, or replace it. I also asked about the estimated hours for removal and installation. According to their system, the estimated time was 4 hours.
The next day, I received a call saying it was ready and they had installed a new bra. I went to pick it up, and I was almost struck by lightning... they wanted to charge me for 6 hours of labor! The reason they gave was: 'it's so difficult to get to, everything was so oily, and we had to change the bracket.'
I found these excuses absolutely ridiculous and I made it clear to them that it wasn't my problem if their technicians were working so slowly, or if they lacked experience with an A6, and that they were taking much longer than the estimated 4 hours. Furthermore, I assume they will install a genuine, correctly fitting alternator, and that they won't need to modify the bracket (I'm still unsure whether they tampered with the bracket or not).
After a brief discussion, the price then went down to 4.5 hours. They charged 30 minutes for checking the old one, which I find acceptable... you can always try to rip off the customer first .
But the real kicker came when I inquired about the price of the alternator, including installation, at Audi... The alternator costs LESS at Audi than it does at Bosch. If Audi had stuck with their original 4-hour labor rate, I would have paid LESS there than I did at Bosch... *sigh*
But everyone has to pay their dues, and next time, they'll ask beforehand with Audi }.

For those of you who might need a new bra from the AFB (presumably a specific brand or store), be prepared to spend around 700 euros. *fg*

Regards,

DENNIS