TDI 150PS: Power Loss Troubleshooting

Hello, I'm having a major problem with my 150hp TDI engine, the engine code is ARL.
The vehicle has now covered 100,000 km. Recently, the performance has been equivalent to a 110 hp engine, and the top speed of 211 km/h (4motion) is not being reached (verified using the Climatronic system).
The fuel consumption has increased significantly (by approximately 2-3 liters per 100 kilometers).
The vehicle doesn't produce much soot, or hardly any at all.
Above approximately 3,000 RPM, the airflow weakens, and there's also a slight 'hesitation,' as if there were some resistance.
The LMM has already been checked and is okay.
There are no error codes stored in the system's memory.
The air filter is new.

What could be the reason for this?

How was the LMM validated?
Did you have a new one installed for testing?
If not, try doing this.
because even if the LLM is still...
'Not being defective is precisely what triggers it!'
And then, the diagnostic system still shows relatively...
Best regards!

For testing purposes, I installed a brand new mass airflow sensor (MAF) that came directly from Volkswagen; everything was still completely original.
I initially thought about that error as well, since this is the third LMM I've had in the vehicle.

Hello,

Is the fuel supply okay? Specifically, is the diesel filter not clogged, are the fuel lines leak-free, and is the fuel tank vent working properly?
Piezo injectors require a "fuel pre-pressure" to function.
Somewhere, there must be a pump that supplies fuel from the tank to the piezoelectric elements. The function of this pump should also be checked.

Best regards, Rainer.

If the fuel supply is insufficient, how can consumption increase? Is there a connection between these two things?

Hi,

I'm experiencing the same problems, although the engine occasionally misfires or stutters after a cold start. Did you discover anything about it?

Hello,

Just try disconnecting the EGR valve temporarily to see if it makes a difference.

Especially when dealing with issues like engine judder and increased fuel consumption in diesel engines, the EGR valve is often the cause.

@leigh

How can a mass airflow sensor (MAF) display "good" values in the engine control unit (ECU), while still being "faulty" or "old"?

The MSTG only reacts to the values that are being read out. If those values are correct (and the intake manifold isn't "too tight"), another mass airflow sensor won't make a difference!

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Perhaps this will help you:
A friend had a stone chip in the lower left corner of his windshield on his Leon Sport with an ARL engine. It was very difficult to see with the naked eye, and we could only hear it faintly by putting our ear close to the window. The effects were similar to what you described. You should definitely check your LD (likely referring to a specific sensor or component) sometime!

But does a faulty EGR valve or mass airflow sensor explain the extreme shaking at idle? The entire engine block moved significantly during that.

Aber werde das morgen mal ausprobieren! Sure, no problem. Here's the translation:

'Thank you in advance.'

Regards,

Chris.

verschandeln your EGR valve; it made a huge difference for me. The engine feels like it has 30 more horsepower, and it's much more responsive even below 2000 RPM! This is assuming that your EGR valve is as clogged as mine was.

Regards,

Chris.

@Chris

What do you mean by "verschandeln the AGR"?

expand; develop; extend; elaborate; build out
- Rinse with brake cleaner.
- install

or how did you do that?

'Yes, that's about it. The intake passage was extremely constricted in my case, and all those deposits naturally caused turbulence in the airflow! Of course, that's not exactly conducive to engine performance.'

I first scraped off the hard crust with your screwdriver and then cleaned everything with a solvent; it looked like new afterwards. When I have more time again, I'll take a closer look at the pressure tubes to see what they look like on the inside. However, the cleaning has already made a significant difference for me.

I once did a pull test from 50 to 100 in 3rd gear. Before cleaning it when it was running poorly, I had about 5.5 seconds, and now I have about 4.9 seconds!

Especially in the range where the turbo isn't fully engaged (below 2000 RPM), the car has become much more responsive.

Regards,

Christian.

Sorry for asking again.

Where did the crust form?

In the intake manifold?

The 038 TDI (G4) engines are built somewhat differently than the 028 (G3) engines.

I'm a bit apprehensive about the thought of having to scrape coal chunks away from right next to the valves!?!?

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

http://home.t-online.de/home/520018906474/motor_oben.JPG

Remove the EGR valve and verschandeln the passage.

GRRR.

Thanks for your tip and the picture, but... as I said..., things are a bit different with the G3.

The AGR is located behind/under the intake manifold .

I'll still try to take a look at it.

Thank you.
m;

http://people.freenet.de/golf-schrauber/TDI_Motorraum.jpg
http://people.freenet.de/golf-schrauber/LDAnschluss.jpg