VTG Hot Clamp

HI,
Golf, see sign.
According to the LDA, when accelerating very slowly, the LD (likely referring to a pressure reading) quickly reaches 0.5 bar. Now, if I hold the accelerator pedal steady, I don't go any faster, and the LD remains at 0.5 bar. However, if I press the accelerator pedal a little more from that point, the LD suddenly drops to 0.3 bar. From that point on, everything proceeds normally.
It only happens when the engine is hot. I've noticed this particularly lately.


Is this already an indication of a stuck VTG (vehicle traction generator)?
Which LDA observer can comment on this?

Best regards, Ronny.

Hi Ronny,

If it were to get stuck, the boost pressure wouldn't drop; instead, it would increase.

Best regards, Rainer.

Hi,
Okay, everything's clear.
I recently replaced the AGR valve because it was leaking at the ventilation hole and installed the sealing caps. I disconnected and sealed the vacuum hose. Then, in the engine control module (ECM), I increased the value of the adaptation channel. So far, it's been approximately 1500 km without any issues.
I did the same thing with the Leon ARL, MSG 038 906 019 KG; in that case, it went into partial load mode after 2 minutes.
Turn on the light. This shows that either: a) a large amount of exhaust gas is being recirculated, or b) the engine control unit (ECU) is very sensitive to the mass airflow signal.

Bye.

Hi.

When making your LDA observations, also consider the engine braking provided by the VTG (Valve Timing Gear).

When you release the accelerator, the VTG closes to generate a lot of boost pressure, which helps the engine to brake more effectively.
This behavior bypasses the "should/is" comparison in MWB 011.

That is to say, when you are rolling, you might have a target pressure of "very little," but a real-world pressure reading of "very much." As soon as you lightly tap the accelerator, the IST pressure disappears.

(This is clearly visible in my ASV logs in the thread "Inspecting ASV boost pressure," and it is explicitly described as a feature on the Honeywell website).

m;

Hi,
"On my loader, even the adjustment nut of the VTG (Variable Torque Geometry) is secured with paint, not just the locknut. I'm going to try unscrewing the canister on the loader while the engine is cold to check for smooth operation. In the default setting during the VTG test, it works well, so I doubt the linkage is jammed." But checking is definitely a good idea.

@dieselmartin
I'm not sure if we're on the same page. My problem is that I have a too-high low-pressure value (LD) at partial load, up to a certain point. Earlier, I was flying with COM at maximum braking power (MWB) 11, and the desired low-pressure value (LD) was around 1100 mbar, while the actual low-pressure value (LDist) was 1600 mbar. I find this difference to be too significant. It's clear that the low-pressure value (LD) is above zero at high RPM and with thrust cutoff, which has always been the case. I also set the pressure to 1.4 bar, but it immediately regulates down to around 1 to 1.1 bar.
Should I run a log analysis in that area? It would be the first time for me.
Do you mean by "ausrollen" (to let out) to fully release the gas, or just to let it out evenly?

RedR32 wrote:

... I recently replaced the AGR valve because it was leaking at the ventilation hole and installed the sealing caps. I disconnected and sealed the vacuum hose. Then, in the engine control module (ECM), I increased the value of the adaptation channel. So far, it's been approximately 1500km without any errors. ...

and because of

Quote:

1998 G4 ALH 110kw@Rainer, red, R32 look

Are you sure that was necessary and makes sense?

Normally, your EGR valve is already being controlled effectively, and you shouldn't need to adjust anything in any of the adaptation channels.

Quote:

I was driving with COM a little while ago, model MWB 11, and the LD was supposed to be at approximately 1100 mbar, while the LDist was at 1600 mbar.

Regulated or dynamic?

Hi,
About a month ago, I checked my intermediate plate and found a hole! It was made of the wrong material and was too thin. The EGR valve and exhaust manifold were heavily carbonized. So, I cleaned everything, and the dilution shower probably was the final blow for the 11-year-old valve piston seal in the EGR valve. That's why it was renewed.
The opening force of the valve was the same as a new one, so it's still okay.

Would a "sensible control system" prevent any exhaust gases from entering the intake manifold?
Okay, the old plates are a thing of the past now. I just hope that I don't get any more error messages like before, especially since I modified the exhaust system (the emissions tax is very high).

What does "eingeregelt" or "dynamisch" mean?
Okay, so I observed the LD (likely referring to a pressure reading) during the trip. The LDist (likely referring to a distance or pressure difference) consistently increased, reaching 1600 mbar, while the LDsoll (likely referring to a target or expected pressure value) remained almost constant at around 1100 mbar. Now, I'm giving it a bit more gas, and the LDist drops to approximately 1350 mbar .
Funny thing.

Create a log.

Hello,
Log will arrive tomorrow or the day after tomorrow, but I have to go back to work tomorrow.

Hi,
The log, only MWB11 and unfortunately with a gear change.
Okay, here's the translation:

"I'm doing one more with MWB8 and 10."

Hi,
MWB 8:10,11

It seems like something is definitely happening... when comparing the environmental conditions, it sometimes occurs in the log, and sometimes it doesn't.

Let's put it this way: As long as the boost pressure isn't too high and the emergency program doesn't activate, I wouldn't do anything major. You might occasionally apply some copper-based assembly paste to the exterior of the mechanism.

Best regards, Rainer.

In the MWB11, there was a brief error message, but then the values reappeared.
Well, apparently, Audi specifies that certain diesel engines in the A8 require the VTG (Variable Turbine Geometry) to be lubricated with oil during maintenance.
I'll see if I can find a 100ml syringe.
If I get a flat tire, I'll change it myself, since I still have a Leon.

No oil! Damn!

Warm up and use welding gloves to handle the VTG rod.
There should still be enough space available at the ALH.

m;

@dieselmartin:

Quote:

When considering your LDA observations, also remember the engine braking via VTG. When you release the accelerator, the VTG closes to generate a lot of boost pressure, which helps the engine to brake more effectively.

Aha...
Do you know that from a reliable source?

Interestingly, the duty cycle increase in the catalytic converter during power operation is more pronounced with stricter emission standards. I thought it was intended to improve exhaust emissions, possibly to prevent the "puff" of smoke that sometimes appears during rapid acceleration from the boost phase.