TDI Smoke: A4 1.9 (AFN) - What's the Cause?

Hello fellow enthusiasts,

After I had worked my way through every corner of the specialist articles,
I would like to discuss my problem here.

The car has been smoking a lot in recent years when driven at full speed (but overall, it hasn't consumed much fuel ). It runs great and doesn't have any other issues.

Despite the new injectors (216 size, installed by the admin), the brand new GT1749VA turbocharger, and the custom chip (also installed by the admin), I can easily leave other cars 'invisible' in my rearview mirror when accelerating hard, starting around 2500 RPM.
Of course, this can also be done with the original control unit and original chip.
When starting from a red light, one might think that I'm driving a cheap, poorly modified car around .

The intercooler piping is definitely sealed tight! It seems that the ESP is simply injecting too much diesel.

Could it also be due to the still uncalibrated measuring device?
I have always associated MSW (Multiple System Failure) with stuttering and similar issues (based on articles I've read).

Before I start working on the ESP system, I wanted to get the opinion of the experts here.

Edit:
Of course, the AGR (Abgasrückführung) is no longer participating in the exhaust . The LD (Ladedruck - boost pressure) likes to exceed its target. The UNREGULATED (meaning the hose from the U-dose is disconnected and the VTG (variable turbine geometry) is at its lower limit) will then be higher than the target pressure. The VTG is common, and the ATL (AbgasTemperaturLeerlauf - exhaust temperature idle) is a brand new VAG part (not a used part). That's why my assumption is that far too much diesel is being injected. The LD and the exhaust smoke have to come from somewhere...

Best regards,
K. Oldewurtel

Hello Kassen,

Please observe the actual versus target injection start timing under full load.

Best regards, Rainer.

Hello Rainer,

I just completed a log ride as a passenger.

I placed the markers whenever the driver saw a thick plume of smoke in the rearview mirror.

It seems (unfortunately) that the injection start regulation is working perfectly.

BTW: I initially wondered about the 0° display (injection start - ACTUAL) during the gliding operation. However, since no diesel (0 mg/stroke) is injected during the gliding operation, the NHG (Nozzle Hydraulic Generator) cannot generate a signal either...

Attached is the log file. I logged MWB004/008/011 to ensure that all relevant data is recorded. However, this does slightly affect the temporal resolution of the measurements.

Could the ESP possibly be suspicious after all?

Best regards, and wishing you a lovely Sunday.

Cash registers.

Hello fellow enthusiasts,

Here's the solution to the problem (too much smoke when starting, smoking, and excessive LD at full load) .

After I managed to eliminate the smoking during startup last year by using two cans of diesel system cleaner on the engine (apparently, the fuel injector was stuck), the smoking at full load and high engine speed turned out to be a much more persistent problem.

After my ESP suddenly became unresponsive and also started to jerk in April, I decided to replace it with a new AT-ESP unit for €800 through the BOSCH service, given that my vehicle had 210,000 kilometers on the odometer.

After installing the new ECU, all of the problems described above have disappeared!
Even under full load and at approximately 4500 RPM, the LD is absolutely stable.

'Even fuel consumption on longer trips at speeds up to 180 km/h (my usual routes in Lower Saxony and East Frisia) has decreased significantly. Previously, it was always between 7.0 and just under 8 liters per 100 km.'
Now I'm driving these routes with a fuel consumption of 6.3 L/100 km - which is a significant reduction!
This also explains the excessive LD (light soot) and smoke production at higher engine speeds – in this operating condition, too much fuel was injected.
During normal commuting (twice daily, 12 km each way), there is no reduction in fuel consumption (low/no full load).

Best regards,

Cash_Oldewurtel

Hello Kassen,

Thank you for your feedback. It seems that the fuel injector nozzle was likely intermittently sticking.

Unfortunately, more and more older cars with the VP37 engine are experiencing this issue these days, which is no surprise, as the cars are getting older.

Best regards, Rainer.

Hello Rainer,

Yes, I think providing feedback is something that should be considered a basic and essential practice.

If people are already offering help for free, then at least a brief explanation of the root cause should be included.
There are always countless threads, but they often lack a definitive 'solution' to the puzzle.

In the professional and paid repair database I use for my official side business, a statement is requested via email two weeks after a help request.
You need to submit a kind of progress report every two weeks until the error is found or the device is scrapped.

Is something like this also automatically possible within your forum?

Best regards,
Cash_Oldewurtel