VW Turbodiesel: Black smoke + power loss

'I've been experiencing more frequent problems with my AAB turbodiesel engine lately.' Right now, I'm not sure where to go from here; maybe you have some ideas.

Current symptoms:
- Black smoke throughout the entire speed and load range as soon as you press the accelerator.
- Low power output; roughly equivalent to running without a turbocharger.
-The engine is overheating; it's running as if it's constantly being driven at full throttle; the radiator fan is running almost constantly.

The boost pressure remains at 0.6 bar above atmospheric pressure from 2000 RPM.

Recently, I experienced the same symptoms; after replacing the diesel filter, everything was fine again.

-Now I've loosened all the diesel lines in sequence; all are okay.
-An ESD (Electrostatic Discharge) strap that was loose, tightened.
-The air filter is almost new (besides, I have boost pressure).


Could it be that the start of fuel injection suddenly changes?

I replaced the coolant reservoir cap just before this because it was leaking.
and the LLD (low-speed idle) is increased via the idle adjustment screw (could that be the cause?).

Or what other reasons could there be for so much diesel fuel to suddenly remain unburned?

It could also be a faulty head gasket or something like that, of course; but let's check the rest first!

Mileage?

Have you checked the fuel injectors recently?

Quote:

-black smoke throughout the entire RPM and load range as soon as you press the accelerator. - Low power output; roughly equivalent to running without a turbocharger. -The engine is overheating; it's running as if it's being driven at full throttle all the time; the radiator fan is running almost constantly.

Injection start delayed?

Possible causes:
- Timing belt/belt drive/sprocket
- ESP sucks in foamy diesel fuel and is therefore unable to build up the pressure necessary for early injection.
- ESP worn out/malfunctioning, with an increasing probability of occurrence after approximately 250,000 km of mileage.

- Injectors replaced approximately 30,000 km ago.
- Engine mileage approximately 130,000 km.
-Total mileage ESP: 340,000 km

He gets diesel without any hassle; next week I'll take the nozzles out and drive to a friend's place where we can get them pressure tested.

Does the AAB - ESP also have a filter at the entrance that could be clogged?

Hello,

engl wrote:

-An ESD that was a little loose, tightened.

Loose ESD straps can get too hot, so this one is currently disconnected. Then you are likely experiencing these symptoms, possibly accompanied by a throbbing sensation.
Replace the nozzle, install a new thermal insulation gasket, and tighten it with 70 Nm.
If that's not the problem, the printer's pressure regulating valve or the ink ejection regulator piston might be stuck. Possibly, I would check that first.

Are you using the original AAB pump with the 8-piston cylinder in your AAB-TD conversion?

Best regards, Uli.

Tonight, I removed the nozzles and cleaned them.
Flawless spray pattern, and the duck fits too.
While reassembling, I noticed that the inside of the laminated glass, where the hole is, was covered with soot.
With new thermal insulation seals, it's running normally again and no longer overheating, even at a constant speed of 150 km/h.

I'm a little surprised about how that could happen. Maybe I got something wrong in the tank.


Thank you!


PS: Yes, it's the original pump; anyway, it's not a race car, and even with a light foot, it doesn't smoke much under partial load.