ASZ: Weakness and Symptoms Explained

For the past few days, I've subjectively felt that the turbocharger in my Golf isn't boosting as strongly as it used to.
Yesterday, I had the opportunity to measure some acceleration times on the Lanstraße on my way home. Let's disregard the first few measurements, where I started above 2000 RPM (it's not that easy to maintain 2000 RPM when you're holding back traffic behind you to keep the car in front far enough away ), the other times are between 7.6 and 7.8 seconds. Let's take the average of 7.7 seconds at a speed of 53 km/h. According to the climate control, it accelerates to approximately 107 km/h at 4000 RPM in 3rd gear. The unladen weight, according to the registration document, is 1310 kg (this is a special Highline model, so I haven't included the climate control and other extras, I hope that's okay). Plus my very light 85 kg, plus 45 kg for a nearly full tank, and my tennis bag in the trunk.
According to the calculation, the result should be approximately 7.3 seconds.
Now I wonder, where did the necessary power for that half-second go?

The car is a 2002 model and nothing has been changed on it. It has 35,000 km on the odometer. There is no unusual black smoke emission, the EGR is active, there is no tuning chip, and nothing has been modified. Everything is original.
Could that be the infamous lmm? But hopefully not after just a few kilometers.

How about using the search function? There's plenty of information on the topic of performance loss, if there even should be any. I doubt that your assumed weight corresponds to reality! You would find something about that in the search function as well...

Calvin wrote:

now I wonder, where did the necessary power for that half-second go

.
Sure, here is the translation of the text from German to English:

"Inclines take 'a lot' of time, so measure them in both directions and take the average."

Accelerating precisely at 2000 rpm will also cause turbo lag.
The DZR (likely referring to a specific engine component or setting) should be operated with full throttle from approximately 1300-1500 rpm, and should be "cut off" at 2000 rpm.

(Although all of this is already described in the DZR documentation, I just happened to have some free time...)

EDIT:
Like Jörg, I also believe that the stated weight is not entirely accurate.
The scale shows the driver (75 kg) and 90% fuel level.
Without the 75 kg, the unladen weight of the base vehicle should be indicated, including items like the climate control system (-> entry "Unladen weight up to xxxx kg depending on equipment" in the vehicle registration document).

@Calvin:

"My ASZ engine from 07/2002 with 33,500 km is behaving exactly the same way. It's getting worse and worse. Yesterday, it wouldn't even rev past 4,000 rpm. I've already deactivated the EGR valve and checked the pressure pipes for leaks. Next, I'm going to replace the mass airflow sensor with a diode and borrow my uncle's VAG-Com diagnostic tool. This can't continue like this."

Interestingly, there have been more and more reports about the ASZ (Air Spring Cylinder) lately. Perhaps it's a systematic error. In one case with a similar issue, a crack in the pressure pipe at the air suspension connection was found. However, that's not the case for me. I hope it's just the mass airflow sensor (LMM), otherwise I might have to replace the diesel filter, which should last up to 60,000 km under normal operation. The air filter was replaced prematurely, but there was no improvement.

Interestingly, it runs really well for a short time after stopping at a traffic light. Do you experience the same thing?
And the loader is noticeably louder than before; even when driving at a constant speed of less than 50 km/h, it now makes a distinct whistling sound that can be heard clearly when the windows are open.

Okay, so my service center replaced the diesel filter for me at 36,000 km. I generally only use branded diesel, and I just replaced it myself (it cost about 22€ from an auto parts store). I also replaced the air filter at the same time, and I've occasionally cleaned the air filter housing and drained the filter. Overall, it hasn't had any noticeable effect (and before these measures, there was no reason to criticize the engine; it runs perfectly). My car has had a noticeable whistling sound from the turbocharger since day one, and it's consistent. When driving downhill, if you release the gas pedal, you can hear it very clearly with the window open. I don't think a normal turbocharger whistle is a bad thing. However, if it sounds like escaping air, there's a reason to carefully check the entire charge air system, especially the intercooler, to see if there's a leak.

Roger wrote:

@Calvin: My ASZ engine from 07/2002 with 33,500 km also behaves exactly the same way. It's getting worse and worse... Next, I'm going to replace the mass airflow sensor (MAF) with a diode.

@Roger + Calvin:

With your mileage , the old Bosch mass airflow sensors might be starting to wear out.

Take a look at the part numbers.

Mine is called...
Bosch 0281 002 461
VAG 074 906 461 B
and is likely already a "longlife" version, as far as I know, identifiable by the "fine grid within the coarse grid" in front of the connector pin (@Gremlin: can you confirm this?).

If your mass airflow sensors have different part numbers, I would suspect the mass airflow sensor based on the symptoms and mileage.

Hi Ulf,
My Golf ASZ (07/2002) has the exact same part number as yours, and it still delivers excellent performance after a dyno test. It would be interesting to know when this type of part was first introduced.

matthiasTDI96 wrote:

Hi Ulf. My Golf ASZ (07/2002) has the exact same number as yours, and after a dyno test, it still delivers excellent performance. It would be interesting to know when this type of engine was first installed.

...while I also think it's possible that the VAG part number didn't change at all when switching from disposable to long-life engine oil, but that the different versions can only be distinguished by details such as the filter grid.

Which would logically imply that the connector, characteristics, etc., are identical.
Then, drivers using disposable LMMs (likely referring to a specific type of component) might hope to receive a long-life part when they get their next replacement.

Let's see what numbers Roger and Calvin have...

How many kilometers (or miles) does your engine have on it now, Matthias?

As an experienced user of LM sensors, I can tell you that it's not like that. When I go for a warranty replacement, I always get the old type due to the vehicle's year of manufacture, etc. Recently, I bought one with a better grid from egedöns (which was significantly cheaper than the highly praised DC parts ). It has a completely different part number. And it works exactly like the 'original.' It has also survived several water fights, which the older version didn't manage to do. The performance curve is the same because the LM sensor modules have the same part number. Only the measuring tube looks different in terms of the grid. If you're interested, I'll post the VW part numbers later.

joergs wrote:

If it's of interest, I'll post the VW part numbers later.

I'd like to know if it's the same as mine.

Based on your experience, do you think that even technicians working with the older LMM system could potentially switch to your version...?

If it's of interest, I'll post the VW part numbers later.
I'd like to know if it's the same as mine.

Based on your experience, it is likely that even ASZ technicians could switch to your version using the old LMM...?

They can do it! I did it myself!

Furthermore, a Bosch HFM5 application guideline states:
'When used in diesel applications, the HFM5-CI model must be used (my note: the 'CI' model is the one with the deflector grid). At the express request of..., the use of the CL model is also possible (my note: this is the one with the single-piece grid).'

And the additional grid (also known as a protective grid) with its inner tube has the following characteristics:
'The deflector grid serves to minimize contamination from water and particles. Water droplets and particles that hit the deflector grid are directed towards the inner wall of the inner tube, where they form a stable film that flows past the sensor.'

And another small note: VW and Audi are operating the HFM5 outside of the specifications set by Bosch.

joergs wrote:

ulf wrote: Based on your experience, it is likely that even ASZ users with the old LMM could switch to your version...? They can do it! I did it myself!

Do you have the AWX, though?
Does your "incorrect" LMM number match mine?

Quote:

Furthermore, according to a Bosch HFM5 application guideline...

Where does he get these "secret" information again?

-> In my opinion, it wouldn't be a bad idea to create a list showing which older CL (catalytic converters) are compatible with which new CI (catalytic converter) types. This would give drivers with CLs that are prone to failure an option to switch to more reliable types.

This could potentially be included as an addendum to the LMM technical article, or it could be published as a separate technical article. Who could gather the relevant data?

I'm already on my way to write down the numbers.

Yes, I have an AWX, and I'm not giving it up anytime soon!

What insider information are you referring to?

joergs wrote:

which inside information are you referring to?

Things like those that Bosch, for example, doesn't include in their publicly available yellow manuals...

Which classified information are you referring to?
Things like those that, for example, Bosch doesn't include in the generally available yellow manuals.

That's probably true! But I often find myself bored on weeknights and just end up browsing the internet.

@Ulf:

Thanks for the tip, I checked just now. They are exactly the same part numbers as yours.
Both of the different grids are included as well.

So, I guess I need to use VAG-Com. Earlier, with the CT, it was even worse; I had to really accelerate to overtake a pathetic 60 horsepower Corsa on the highway .