Problem with BLS motor, integrated PD elements

Hello everyone,

I'm asking for your help as I'm at a loss.

It concerns a BLS engine with DPF on a 2007 Skoda.

The mechanic said it was a "NW defect". So I replaced the "NW" with hydropneumatic and swing axle (which was also already worn), but there was no change.

Zitat:

I made a video showing the oil pressure. The problem starts around 20 seconds in the video. If you search online for "BLS engine problem", you might find something.

So, the engine starts cold just like warm, perfectly. It runs quietly at idle. However, around 2200 RPM, there is a tapping/knocking/clattering sound.

I've been working on it for about 50 hours now, and I'm not sure what to do next.

2 PD elements are new: 2 + 3 cylinders, connecting rod bearings also checked, OK.
Compression is between 26 and 28 bar for the 4 cylinders.
Valve timing has been checked several times, OK.
Oil pressure at idle speed is constant at 2 bar at approximately 2500, as also in the video at approximately 5 bar.
Oh, and nothing in the fault memory. I've also attached a log during operation.

I would appreciate your help, I am grateful for any tips.

Best regards, Tom

Edit: Autoservice: Log fragments removed

Sounds like a carpenter's work.

Unfortunately, it's not possible to tell exactly whether it's the sound of sanding/scraping, or perhaps a hissing sound, possibly from the turbocharger or the intake, and not to know when and how the sound appears, develops, and disappears again as the engine speed decreases.
Is the turbocharger okay? Is the boost pressure pipe sealed?

A few more details about the symptoms or repair attempts would be very helpful.

Please post the log files as a CSV file "as saved by VCDS". This format is easy to understand.

Hello,

So, I checked the turbocharger by making sure that the shaft can be turned slightly and that there is no axial play. The intake path is also clear!

Well, the rattling/clattering started spontaneously, and then the mentioned that the timing chain needed to be replaced (it was also damaged).
It's really a clattering/rattling from 2200 RPM, with no hissing sound.
I also checked the timing chain, as there are versions with and without DPF.
Oh, and when the rattling starts and the RPM drops, the engine takes about a minute to adjust itself.

Best regards, Tom

Based on your description, it could be the hydraulic lifters. This would also suggest a worn camshaft.

Possibly a partially blocked oil channel, which means that the oil supply is no longer sufficient for the hydraulic lifters at higher speeds.

Hi Tom,

please write something more technical, less "emotional prose".

Zitat:

Replacing the camshaft (it was also broken).

I think, obviously, it was broken into 1000 pieces, and one is now somewhere in the oil circuit, rattling.

Okay, it won't be like that, but what damage did all the replaced parts have?

Was was possibly not replaced enough - were old seals used or similar cost-saving measures implemented?

If the engine is allowed to idle quietly after the "wild ride" in the video, i.e. to run in neutral, will the rattling eventually disappear?

Can you make more audio recordings like this?

Hi,

Sorry, so the camshaft was worn on cylinder 4, specifically on the exhaust valve, more than on the intake valve.
The hydraulic lifters were also worn there, but only with scratches, nothing broken.
I was also considering the possibility of contamination in the oil channel, but I'm hesitant about using such system cleaners.

And yes, the engine regains its idle speed after a while (a minute or so).

Best regards, Tom

Hi

The description and the noise seem to match "hydrostatic valve".

If it is often and quickly pressed, i.e. at speeds above idle, it will break, and the corresponding valve will rattle.
If it is rarely and gently pressed (idle), it will have more time to fill and hold the oil.

Thanks for your reply, so you mean that one of the new hydros is faulty or has a blocked oil passage?

I immediately removed the valve cover and the hydros were all hard, indicating they were full.

What other testing options are there for the pistons, so that I can also get an idea of where to look?

Best regards, Tom

That's not helpful. Your information is simply... inadequate.

If the goal is to provide assistance, it requires proper communication from which something can be derived. I don't want to have to extract information piece by piece.

1. Vehicle (with or without balance wave module)? edit: Sorry, 1.9 2V, of course without.
2. Mileage
3. When did the noise start? Was it before or after the NW (no-load) replacement?
4. Was the cause of the NW damage investigated, and is there lubrication in the cylinder head?
etc.

What can be safely ruled out as a source of noise so far?

Hi,

Thanks in advance for the quick responses.

1. Vehicle (with or without balance shaft module)?
Normal oil pump without balance shaft module, I think only the 2.0 16V TDI have these?
2. KM Stand
140000
3. When did the noise start – before or after the NW replacement?????
The noise was the reason we investigated, and that's when we saw the issue with the camshaft.
4. Was the cause of the NW damage investigated, and is there lubrication in the head?
So, I think it's definitely after the engine is turned off that the hydraulic lifters are full. The camshaft bearings also looked very good, so I think the lubrication is working.

What can be safely ruled out as a source of the noise so far?

We have checked the connecting rod bearings, turbocharger, and compression (to rule out a piston failure...).
We have also temporarily disconnected auxiliary components such as the Lima, etc. (which also revealed some interesting issues).
We have checked the valve timing multiple times.
We have replaced 2 PD elements because the noise was coming from cylinders 2 and 3 (assumed), and I will be installing 2 more today because it sounds like they are dripping.

Have you ever had a crack in the cylinder head from the diesel fuel line to the fuel injector, where fuel might be leaking?

If the other two fuel injectors are not the problem, I will remove the head, take a look, and see if there is actually a defect in the fuel injector or the cylinder head itself. I will also be able to see the condition of the bore.

Best regards, Tom

Hi Smudo!

smudoo hat folgendes geschrieben:

...I've been searching for about 50 hours now and I'm not sure what to do anymore. ...

It seems like a lot of time and money, but I have even less of a plan. :lol:

Please make another pure audio recording of the sound and upload it HERE as well. (Click "edit" in the top right corner, then "select file", etc.)

Also, I would like you to perform a LOG on the MWBs 13, 18, and 23, preferably in standby mode, if the problem exists.

Based on your previous posts, the previous troubleshooting and fault isolation were carried out by completely random part replacement.
Are the PDE's so cheap and easy to remove and replace that you're considering using them? :wink:

Again:
First, create a proper audio file with precise (time) indication of when the noise you are complaining about starts and ends.
Then, upload LOG 13/18/23 while the machine is idling and experiencing an error, also with (unclear!) timestamps. It needs to be clear from which cylinder the problem originates!
...and stop introducing further errors by completely unnecessary part replacements... :roll:

Best regards from Munich!

Hello,

So, I replaced the PDs because I had disconnected them, and on the 2+3 cylinder, the noise was no longer audible. When I disconnected them individually, it might have just been a coincidence, or perhaps others were also defective.
I will try to get a better recording tomorrow.
Attached is the log, the last 50 lines are in idle!

Thanks in advance.

Best regards, Tom

Zitat:

So, I replaced the PDs because I had disconnected them, and on the 2+3 cylinder engine, the noise was no longer audible. When I disconnected them individually, it might have just been a coincidence, or perhaps others were also defective.

I don't understand anything. What country are you from, if I may ask?

Please rephrase and organize the section in a more understandable way.

Hi,

Okay, I disconnected the PD elements one by one (simply pulled out the connector for the solenoid valve) and the noise was gone with the 2nd cylinder (I thought it was a faulty fuel injector), well, and when they were replaced, it was also fixed with the 3rd. The engine then only ran on 3 cylinders, well, and the clattering/knocking was gone, but obviously just by chance.

I'm from Austria!

Best regards, Tom

Hi Smudo!

smudoo hat folgendes geschrieben:

... I'm from Austria!...

Okay, then that's clarified. The only question remaining is where the country is located? 8)

The 13/18/23-LOG doesn't show any anomalies, and the values are actually very good.
Therefore, I would advise against using PDE's, as that would be a mistake!
It seems the problem affects either all or none of the cylinders, otherwise there would be an anomaly in the LOG.

Please create an audio file and upload it here.

Best regards from Munich!

Zitat:

The 13/18/23-LOG does not show any anomalies, and the values are actually very good.

In Log line 143, MWB18 ---> "n128 = No closing time identification (Begin of Injection Period = BIP) possible (Motor OFF OR electrical fault)"

I only know this when the motor is in the sliding operation and then at all 4 cylinders simultaneously, but it could also be due to 2 data recordings.

From line 145, the engine control system is behaving erratically on cylinders 3 and 4.