Leistungsmangel / Rauchbegrenzung AVF | Posts 16+

Hi there.

No, the valve seat is sealing completely.
I had already suspected something about the feather, I've read quite a bit on the subject, and I think it's mentioned in the article. Otherwise, I held the thing in my hand, and you can't open the valve just with finger pressure; you really have to push harder.

Yes, I've heard of plain bearings. But technically speaking, it's a dynamic hydrostatic bearing. So, it's only lubricated when there's oil pressure applied.
Ich hatte halt nur gedacht, dass wenn die Turbine so schnell dreht, dass es dann auch ohne Öldruck ein wenig mehr nachläuft. Egal.
It always gets stuck on one side, as if the wave has been eaten away.
"I'm familiar with this from mechanical engineering; we have pistons that move up and down within a casting, and sometimes you can feel it if you rotate the part."

Today, I'm going to try loosening the exhaust pipe a bit, as Rainer suggested.
It will probably take me one to two days to get back to you.

Best regards,
Florian

Okay, I now have a small gap between the turbocharger and the flexible pipe.
Unfortunately, I couldn't find any other options.

I've been reflecting on things again, and I realized that I actually did once get arrested, but it was quite a while ago, and I don't remember the details very clearly anymore.
But then I immediately checked the car (I was at my parents' house, and they have a metal bollard in the middle of their driveway for the gate) and couldn't see any scratches or abrasions.
And just recently, when the performance issue was already present, it happened again, during a very steep and completely awful incline.
My friend (who runs a workshop and where I always get my car inspected) also asked me if the car has been lowered, but I have no idea.

Tomorrow I will be conducting the test run.

Now I have another question!
Could the air filter box melt now that I have a small gap between the turbo and the flex pipe?
Because the hot air is now rushing out from there...
It shouldn't be a permanent condition anyway, but maybe the short distance is enough.
Because an air filter housing can easily cost around 150 euros.

Well, tapping the cat (that small thing right after the flex piece) didn't do anything.
It didn't sound hollow or anything like that, and unfortunately, I also have no idea what it *should* sound like. Therefore, RedR32's objection is justified in this case...

Anyway, I can provide a log file with the resolved exhaust issue tomorrow evening.
Best regards,
Florian

Quote:

Now that I have a small gap between the turbo and the flex piece, could the air filter box melt?

Sure, that's why we only test for a very short distance, and around any parts that are heat-sensitive, we use things like disposable aluminum foil containers to prevent heat damage.
You'll notice if the car starts running better after just 100 meters, so you don't have to drive around for too long until it breaks down.

Best regards, Rainer.

[Translating...]

Habe bei meinem Problem https://community.dieselschrauber.org/en/viewtopic.php?t=26673 ein Blech zwischen Luftfilterkasten und Turbo/Abgasrohr gestellt, bin sicher 10km so gefahren, weil mein Problem ja nicht immer da ist.

Okay, unfortunately, I wasn't able to complete the calibration run yesterday evening.
Now I'm submitting it again.

As I said, it's just a small crack, nothing major, but it does show some effect!
I have now temporarily exceeded the 1000 mg/hour threshold.
If I were to create a larger gap, I imagine that the values would revert to their previous ones.
I'll see if I can get under the car today after work.

As I said, I've had it installed twice already, so maybe the exhaust pipe got something on it and has become clogged over time; it's possible!

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

"By the way:"
Is it normal for the exhaust manifold and turbocharger to have a reddish discoloration on the metal, on the exhaust side? Or does this indicate overheating?
I can rule out rust because it's always dry there, and it looks different anyway!

Gilliearnie wrote:

As I said, it's just a small crack, nothing major, but it does show some effect! I have now temporarily exceeded 1000mg/H.

A small improvement starting around 3000 rpm is noticeable in the logs, but the engine still hasn't cleared up completely.

Quote:

As I said, I've had it installed twice before, maybe the exhaust pipe was affected by that and has become clogged over time, it could be!

That would generally be a conceivable cause. If possible, please post some pictures of the damage!

Quote:

Is it normal for the exhaust manifold and turbocharger to have a reddish discoloration on the metal side,

or does this indicate overheating?
I can rule out rust because it's always dry there, and it looks different anyway. If the reddish color (in the dark) glows, then the material is glowing. }
Otherwise, an external reddish discoloration of the OEM AgA components, including the turbine housing, is not unusual.

Okay, I'm going to try getting under the car today.

I also know what glowing metal looks like . However, it's more of a dark red color, and that's in its cold state. Otherwise, I wouldn't be able to write anything now, because I would probably have severe burns on my hand...

Okay, I lifted the car on the passenger side with a jack so I could look underneath. Getting under it near the sidewalk is always a bit tricky.
The exhaust pipes are extremely rusty.
The catalytic converter is included, but the center silencer is not; only the inlet and outlet are present.
While lifting the vehicle, some liquid came out of the muffler; I suspect it was engine oil or something similar, as that's what it smelled like.
Oder aber Kühlflüssigkeit? Asubject: Where from?
It was definitely a greasy and light liquid (between my fingers).

I took some pictures.
It looks like the exhaust will probably need to be replaced soon anyway, or what do you think? After reassembling the connection between the catalytic converter and the turbo, I did another logging run. I've attached the log file.
I'm also attaching the pictures I took of the exhaust. I haven't found any significant stress points, just a slight bend in one spot, after the mid-section muffler (I think it's the larger one). There's a picture of that as well. (But it's hard to see, unfortunately.)

It seems like the bend in the pipe is located above the HA unit.
If there is no sign of a crimp mark indicating the impression of a neighboring part, it is likely that the pipe has its original factory shape. My BUK also has something similar on the bend above the rear axle.

How certain are you that the AgA was triggered? Because the forces generated when it detonates (if it's a proper explosion) should leave clear traces, but none of those traces are visible in the pictures.

The soup from the end cap seems strange to me. Could it be cavity wax that melted on the warm end cap and dripped off when I lifted it (so, not from the end cap itself)?

In any case, I can't identify any AgA (air gap alignment) issues in the images that could explain the motor running in a degraded state.

Enjoy your meal! / Have a good lunch!

I went to the doctor again today about my car.
This time, I lifted the right rear corner so that I could get a better photo of the area with the bend.
It's only very slightly indented and is actually located on the rear end.

I'm not sure if I have a problem with my AGA (anterior cruciate ligament). As I said, there's absolutely nothing visible!

I just spoke with my friend who runs a car repair shop. I signed up for the upcoming service and explained the problem to him. He then told me that it's possible the exhaust pipes are double-walled - meaning steel on the outside and stainless steel on the inside? Is there such a thing, like a "sandwich steel" construction?
That would certainly explain the high price of €580 for the entire system, including shipping from the factory.

I then explained my problem to him, and he immediately said that it could also be the "Kat" component, which might be collapsing internally and causing the ceramic part to obstruct the flow. He could get me a replacement (from their accessories) for €300.
At the auction house, they already start at €130, but it's probably not even made with platinum.

I still couldn't quite pinpoint the origin of that soup.
I checked inside the exhaust pipe again, but it was completely dry (as far as I could see).
I'm going to have him remove the exhaust system now, and then he'll inspect it and replace the parts that are causing the back pressure. That's definitely the problem!

Thank you for your help, and I'll get back to you when I have the car again.
However, this is most likely to happen next Friday (August 24th).
I have to be away for work this week and next week.

See you later!

Good evening everyone.

Okay, the car is back from the workshop, and they removed the exhaust system. They also took off the catalytic converter. They didn't find any blockages, and the catalytic converter isn't clogged either!

DAMN!!!!

What now?
So, I had a rather lengthy conversation with the workshop supervisor.
He also made a good impression on me, and he himself drives a VW Passat, specifically the 3B model from before 2001, with a diesel engine, so he understands the issue of lacking power.
He then told me that the EGR valve and the bypass valve (is that what it's called, attached to the EGR valve?) are defective and not switching properly.
Then I thought, what if the control valve for the EGR system isn't working correctly and is defective, not closing properly. Doesn't the vacuum also increase with increasing engine speed? Could it be that the defective control valve causes the EGR to open at higher speeds, leading to a loss of air mass in that area?

I thought about that, and I had the same idea regarding the shut-off valve.
What if this check valve is also defective and the flap doesn't close completely but moves in one direction? Then it would also cause a restriction.

So, I removed both vacuum hoses, closed them with screws, and went for a test drive. At first, I thought: Yes... problem found! Finally!

But then came the disappointment when I checked the actual value in between.
Leider immernoch die gleichen Probleme! Damn...

In the workshop, the turbo was checked again; they examined it and even rotated the impeller blades. They found everything to be normal and okay.
The VTG (vertical travel gauge) was also easily adjustable and moved within the normal range.

Okay, so what could it be?


By the way: I added about a liter of oil a few kilometers ago. At that point, my oil consumption was 1 liter per 25,000 km. I don't think it's too bad! Can we just ignore it, or?
But what if the low-voltage cut-out (LLC) is now full of oil and flooded?

Well, I've reattached the measurement data; you can take another look at it.

Best regards,
Florian

Gilliearnie wrote:

So, what could it be then?

I had already written:

Quote:

Another possible cause: EGR soot buildup in the intake manifold (including the valves!), which was not removed during the EGR cleaning mentioned in the post.

Has that been checked in the meantime?

Hello Ulf,

I took the EGR valve off again last week.
Before I installed the gap after the turbo.
In that process, I had to completely remove the intake manifold.
It was full of oil soot, but not to the extent that it would significantly reduce the cross-sectional area.
Unfortunately, I forgot to take pictures of it, but I did verschandeln it.

I also inspected the valves and was initially puzzled as to why three were closed and one was open. However, after a moment of thought, it occurred to me that the valves naturally open and close differently, and are opened and closed via the camshaft (as far as I recall...).
But I was very careful and also removed a little bit of the oil soot with a knife.
It was completely mushy and maybe only a millimeter thick, so it wasn't worth talking about!

I have cleaned the intake manifold, EGR valve, and valve chambers (or whatever they are called).

I had already described that in detail before. (Post from August 10, 2012)

I'll probably have to take the pressure side apart again between the EGR valve and the turbocharger and check it more carefully. I've looked at it before, but maybe I missed something this time... I didn't remove the water pump back then.
Only the hoses were removed.
Vielleicht hat sich da innerlich der Querschnitt verjüngt?!? Let's see.
However, it will take some time again; I'm on a business trip to Finland once more...

Best regards,
Florian

Okay, I'm ready. Please provide the German text you want me to translate into English.

Okay.

Okay, so let's adjust the VTG (Variable Turbine Geometry) by turning the adjustment screw, right?


Where can I measure the oil pressure?
Is that somehow possible? Or does the AVF engine not have hydraulic lifters that actuate the valves?

Best regards,
Florian

Quote:

So, let's adjust the VTG adjustment screw, okay?

No, you should really put some effort into thinking about whether someone incompetent might have been involved in this.