Golf III AFN Engine: Low Power? Troubleshooting

Hello there,

Luckily, I found my way to this forum, and I hope someone can help me.

Background:
Two weeks ago, I bought a Golf GTI TDI 20 Years Edition. The engine was rebuilt about 2,000 km ago by a company that offers a 1-year warranty on the engine. Because the engine was new when I bought the car, I didn't initially notice that it wasn't delivering its full power. It wasn't until I drove a friend's TDI, which also has the same engine (AFN), that I realized my car felt sluggish.

Problem:
The engine lacks sufficient power, and the vehicle only reaches a speed of approximately 170 km/h.

Attempted problem-solving:
- rescheduling the start of funding.
- Air mass sensor replaced.
- Measurement data blocks evaluated in the full load range.

Unfortunately, none of those things have achieved the desired results. The measurement data blocks contain all the specified values (I can post them here if needed).

If anyone has an idea, I would be grateful for any suggestions.

Regards,
Sascha.

Hi,

This issue has been discussed many times in this forum! Do you have a boost pressure gauge? That would definitely be helpful in troubleshooting.

How does it behave during acceleration? Is the acceleration "wavy," meaning does it have more or less power at different times?

Are the injection quantities within the normal range ?

See you later.
Achim.

First, let me ask a question upfront:

Why did you stop using the FB and switch to the LMM?

Did the two of them have anything unusual or noticeable happen before?

m;

The start of the boost was outside the tolerance range, so I had to readjust it.
I only replaced the mass airflow sensor for testing purposes, and it wasn't a problem since I work at a car dealership.

Unfortunately, the vehicle doesn't have a boost pressure gauge, but the diagnostic data display shows the boost pressure as well.
The acceleration remains constant across the entire speed range.

Display group 00, under full load:

Motor speed: 141.
Injection start: 166.
Accelerator pedal position: 255.
Injection amount: 204.
Intake manifold pressure: 194.
Atmospheric pressure: 204.
Coolant temperature: 74.
Intake air temperature: 176.
Fuel temperature: 107.
Intake air mass: 255.

Ad group 10, running at full capacity:

Air mass ingested: 925 mg/H.
Atmospheric pressure: 1020 mbar.
Intake manifold pressure (boost pressure): 1785 mbar.
Accelerator pedal position: 100%.

// Edit: The car always starts without any problems, whether it's cold or warm, and there's nothing unusual about it.

"Could you please perform a classic 003-010-011 log over a certain period of time? For example, during a DZR test (which involves full throttle in 3rd gear from 1500 to 4000 RPM)."

One should be able to recognize quite a few things from that.

And it can be used in many wonderful ways:
Here is where the Russian border ends:
http://www.luxus-wg.de/~martin/auto_bilder/LMM_defekt.jpg

Here, you can see the LMM (lambda-dependent mass) dropping starting from 3000 RPM.
http://www.luxus-wg.de/~martin/auto_bilder/LMM_soll_ist_ueber_Drehzahl.gif
http://www.luxus-wg.de/~martin/auto_bilder/LMM_soll_ist_ueber_Zeit.gif

Hi.

Quote:

Intake manifold pressure (boost pressure): 1785 mbar

too low, if measured correctly: approximately 3000 RPM, and in the regulated state, meaning at least 2 seconds of full throttle.
If the engine is getting enough diesel (check the diesel filter and for leaks), then check the turbocharger boost pressure control.
You can tell if something is wrong by looking at the duty cycle of the boost pressure control valve.

Best regards, Rainer.

Please run a classic 003-010-011 log for a certain period - for example, during a DZR test (which means full throttle in 3rd gear from 1500 to 4000 RPM).


Unfortunately, I only have a VAG 1552 available, which allows me to read the values for a short time only, and I can't even print them. Therefore, it will be difficult to create a log file.

I will double-check the intake manifold pressure again.

But I was wondering if the catalytic converter might be too restrictive, as that could potentially be the issue, right? Unfortunately, I'm not really sure how to check that.

Sure, it could be the cat.

However, it's also possible that the nozzles are clogged, that a vacuum is building up in the tank, that various filters are blocked, and so on.

Get yourself a VAGCOM and log some values - it's cheap and quick!

m;

I found the problem with the boost pressure; a small crack in the boost pressure hose was the cause. Now I have 1897 mbar, but even the 1785 mbar was still within the acceptable tolerance range, which extends from 1700 to 2500 mbar.

While using VAGCOM might be a great idea, I don't think it's a good idea to spend money on it just for that purpose.

I'll take the cat out this weekend and shine a light inside to see if I can make out anything.

Well, if you'd rather spend your time tightening the turbo's cat, buying a new gasket, and new screws, instead of using a VAGCOM diagnostic tool, then please do.

It could also be the intermediate pot or the final pot...

The parts for this Kat-Oracle are almost as expensive as VAGCOM.

And if you say you're reusing old parts, we're already talking about two completely different things, because those parts are usually completely rebuilt. (Reusing is a lot of tinkering.)

http://shop.dieselschrauber.de/product_info.php/cPath/21/products_id/38

m;