Compression loss AXR 1.9l TDI-PD/74 KW

Hello community,

I own a Golf IV with the original AXR 1.9l TDI-PD/74 kW engine, produced in 09/2001. The mileage is currently 61,000 KM.

During the inspection last week at a VW specialist workshop, the owner mentioned to me that the master had pointed out the somewhat uneven, slightly shaky engine run during the test drive in idle. However, the engine had already exhibited this behavior from the time of purchase at 12,000 KM. During the subsequent inspection at 20,000 KM, I mentioned this to the then-current master (at another VW specialist workshop), and we drove the car together. He then said: 'That's normal for PD-TDIs...' The engine runs perfectly smoothly, round, and vibration-free from approximately 1000 RPM, has full power, and consumes a constant 0.3 liters of oil per 1000 KM.

Now, as part of the inspection last week, a functional test of the PD units was carried out at the recommendation of the inspector. The following results were obtained:

- PD units
Cylinder 1-4: 00 Error-free control

- GDP - Deviation
Cylinder 1: -13 us
Cylinder 2: -31 us
Cylinder 3: 5 us
Cylinder 4: -10 us
BIP Deviation OK

- Idle Time Reduction Regulation
Cylinder 1: 0.21 mg/h
Cylinder 2: -2.14 mg/H
Cylinder 3: 0.19 mg/H
Cylinder 4: 1.69 mg/H
Idle-time reduction control is functioning correctly.

So, according to the master, this does not yet allow for a conclusion about the cause of the uneven engine idle, although it seems that a deeper defect, apparently 'compensated for,' is being caused by the engine management and, consequently, the PD units.

The subsequent compression test then revealed the unpleasant truth:

Cylinder 1: 56.8 Bar
Cylinder 2: 56.8 Bar
Cylinder 3: 54.2 Bar
Cylinder 4: 49.1 Bar

Therefore, a compression loss occurs in cylinder 4. What other causes, besides a leaky valve, broken piston ring, crack in the piston, or a 'jammer/eater' in PD-TDIs, can lead to this? Are there any further data points available?

My thoughts are also to take advantage of the first workshop inspection (inspection at 20,000 KM), as the issue with the slightly uneven idle was already present at that time (and was noted in writing on the delivery document for inspection), likely with the same cause. With a mileage of 20,000 KM and a vehicle age of 16 months, a warranty claim from the manufacturer's side would have been very likely, unlike today.

For further tips on possible causes and the next steps, I would be grateful to you.

Best regards,
Christian

Hello Christian!

Your idle speed control actually looks quite unstable – however, it's still within the limits.
Your compression values, however, are making me suspicious. I just checked what the recommended limits are for my engine (1.4PD). And that would be:

New: 25-31 bar
Wear limit: 19bar

Pressure difference between all cylinders max. 5 bar.

Are you sure that the measurement was correct? I find a compression pressure of around 60 bar to be very high, especially since the engine has already been running for a while. Therefore, I wouldn't give that much importance to it initially. I think you should rather be looking for problems with the PD (Powertrain Control) elements. However, Bertil had also written several very interesting articles that could be found through searching...

Best regards,
Dirk

Hello Christian,

I'm glad to see another AXR user among diesel engine enthusiasts

The likely cause of the rough idle is the engine control unit, which was installed in the first series of engines.

The professional handyman, Bertil, has written a lot about this:

/viewtopic.php?t=1671&highlight=axr

Regarding the alleged compression loss and the test values, I have no experience and therefore cannot comment. However, someone else here will definitely be able to provide you with expert information on this.

But you certainly don't have to bear the repair costs alone.

VW offers goodwill up to a vehicle age of 4 years or a mileage of 100,000 km upon request.

From your text, I understand that you purchased the car used.
If it was 2002 and at a VW dealer, you would likely have a 2-year used car warranty, which might still be in effect.

Best of luck and greetings,

Marcus

Christian S. wrote:

Cylinder 1: 56.8 Bar Cylinder 2: 56.8 Bar Cylinder 3: 54.2 Bar Cylinder 4: 49.1 Bar ...

Hey, can you show me the 827 model that's used in the factory?
First Impression: Measurement Error
Second Impression: Today, many workshops are still unable to correctly use VW's own information system.

/viewtopic.php?t=1726

The following document is an excerpt from the VW error database. Your car falls precisely within the specified date range. Checking the STG number should be easy with VAG COM or with VAG testers (except for the "Crystal Ball" ).
As far as I remember, the values for the idle speed control at the ..019CR STG were also a bit off for me. With the ...019MQ, everything is now back to normal.
By the way, my workshop also performed a compression test, as they suspected a serious engine defect. The reason for this was that the first mechanic who attempted the VW repair didn't believe it ("... "The STG change doesn't really make a difference...").
This process reminds me so much of the one I used with my AXR...

Have you noticed any changes (amplification) in the vibrations over time?

Hi,
0.3L / 1000 km is quite a lot, even though the limit is 1 L / 1000 km. It is normal that one does not have to refill anything between oil changes, during the 15,000 km interval, so that the consumption is less than 0.06 L/1000 km.
That would certainly point to a defect in the cylinder-piston area.

Hello,

Thank you for your previous responses.

@bertil: Do you have more specific information or perhaps links regarding compression values and corresponding wear limits for the AXR? If there is indeed a measurement error that exceeds the theoretically achievable pressures, then the only options left are valerian or a consultant...

Since I have an appointment with the workshop manager tomorrow afternoon, I would appreciate any suggestions you have regarding the next steps.

Best regards,
Christian

Hi Christian,

Christian S. wrote:

@bertil: Do you have more specific information or perhaps links regarding compression values and corresponding wear limits for the AXR? If there is indeed a measurement error that exceeds the theoretically achievable pressures, then the only options left are valerian or a consultant...

The appropriate values have already been posted by "brezelmann01" above. Your local VAG dealer can also retrieve this information from the VW information system.

Hello, the compression values are most likely incorrect.
There are two possible causes for the irregular idling:
1.: Your double-mass flywheel is damaged.
2.: A pd-element is defective.
Unfortunately, we cannot determine any difference based on the diagnosis.
In your place, I would first replace the two-mass flywheel (3 or 4 replacements are likely).
If that doesn't work, you'll need to invest in a replacement head, including PD elements.
Before, it's also a good idea to politely inquire about a possible goodwill gesture, perhaps by calling the service number yourself.
The error is known in both cases.
A little bit of pressure on the tear ducts while being friendly and saying that you always had a car, for example, and then it works.

mersente wrote:

There are two possible causes for the irregular idling: 1.: Your double-mass flywheel is damaged. 2.: A pd-element is defective. ....

Another person who stubbornly refuses to accept the service information provided by the manufacturer
At VW, there is a publication regarding the STG (Software Update) for vehicles in this production period that specifically addresses this error (see above).

Of course, these two defects can also occur.
I'm skeptical that after 50,000 km with a faulty WMS or a faulty PD element, the fault will not change. Furthermore, these errors would also become noticeable during driving (at least normally), but that is not the case here.


@Christian S.
If you have formally reported the defect in writing during an inspection while the warranty was in effect, then the prospects for a warranty/goodwill claim are not bad.

Hi!

So, ich habe auch ein AXR EZ vom 08/01. I had the same problem: Very rough idling, but mainly when it was warm.
Then I drove to the dealership, and they, due to the internal information system of VW, retrieved the data block 13, with the following result:

http://home.arcor.de/vipviper2000/pde_einheiten.jpg

So, daher wurden alle PD-Elemente unter Garantie mit einer Selbstbeteiligung von 200 € ausgetauscht. Und das hat NICHTS gebracht. Das Ruckeln war immer noch vorhanden. Dann weiter im Informationssystem gesucht, und das hier schon mehrfach gepostete Dokument gefunden (das mit den lustigen Formulierungen). Deshalb wurde dann bei mir das MQ Steuergerät eingebaut. Ergebnis: Ruckeln weg! Zumindest fast. 'He still wobbles a bit now and then, but much less than at the beginning.'
Now I don't know if this is normal, or if something is still wrong.
Could you perhaps help me with what else I can/should measure in order to potentially... Identify the root cause.

Or, if you, PD drivers, could share whether your cars run completely silently in neutral, meaning you can't hear anything inside the cabin at all.

Greetings,
VipViper2000

P.S.: I don't want to be seen as a 'big spender' anymore and I don't want to have something repaired that isn't actually broken.

Hello,

My AXR is not affected by the described problems with the PD elements and the MSTG from the first production weeks. However, there are occasional vibrations in idle after a cold start. These are just isolated vibrations that do not bother me, and I think this is 'normal'. The engine generally runs with fewer vibrations than, for example, an ALH engine, which I once drove in a GIV Variant.

I am currently concerned about the reports regarding defective clutch assemblies and two-mass flywheels from the Golf IV forum, particularly for the 74KW TDI engine. There have already been about a dozen people who have reported damage at a mileage significantly below 100,000 km.

If they've actually installed such a small clutch, and there isn't a more durable replacement available, then this clutch will probably separate me from my AXR if it fails.

Best regards, Marcus

Hello community,

Here is the official final diagnosis of my malfunctioning AXR:

1. The initially posted compression values of over 55 bar were, as you suspected, a TOTAL MISREAD (!?). Now, all 4 cylinders are within 1% at approximately 25 bar. What I find particularly puzzling is that the 'treating KD master' apparently has no sense for these values - he should have definitely noticed that these are not realistic values. The VW company also has a racing department and uses the 996 in the Carrera Cup... apparently, this doesn't help at all. I have successfully recovered the payment for the measurement activities.

2. The workshop No. 2 then discovered that a PD element was defective - according to the manufacturer's instructions, all 4 had to be replaced for the installed type (AT: 1200 EUR). After extensive efforts by the manufacturer's representative, VW now covers 50% of the total cost of 1500 EUR as a gesture of goodwill. I am currently writing a letter to the sales center in Ratingen, as I do not see any reason to bear the remaining cost myself. The symptoms appeared as mentioned, already at around 20,000 KM - at that point, there would probably not have been much discussion about a 100% warranty claim from the manufacturer. The control unit of my AXR appears to be functioning correctly.

Okay, thank you all very much for your helpful advice!!!

Best regards,
Christian