V6 TDI Intake Manifold Pressure

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I have a Skoda Superb V6 TDI with an auxiliary control unit from www.masterpiece.de.
'Occasionally, I get the error message 'Intake manifold pressure exceeds regulation limit' in the error memory.'
The engine then cannot be revved above 3000 RPM for approximately 30 seconds. However, sometimes it is enough to release the accelerator and then press it again.
and it continues to accelerate normally.

'It's not a big deal, as it only happens at exactly 210 km/h, and even then, only once or twice a month, with a monthly mileage of 5000 km (although I'm usually not driving that fast).'

Okay, here's my question:

Is this due to the tuning? Is the tuning too aggressive (from 155 horsepower to 183 horsepower)?
Could the problem also be due to a defect in the vehicle?

Point b), if you follow the link in the first part of this post.
b) If the boost pressure is too high (exceeding the regulatory limit), the most common cause is usually a stiff or jammed variable geometry nozzle mechanism in the turbocharger.

The error first appeared at approximately 3000 kilometers, and I have now driven 25000 kilometers.
(The fact that the problem occurred after only 3000 km makes me doubt that it's a stiff guide vane adjustment – or is it? )

Thank you for your answers.

Hello,

It could also be the solenoid valve that supplies the control pressure/vacuum to your adjusting valve.
Depending on the electrical control, it allows different amounts of pressure/vacuum to pass through (I'm unfortunately not familiar with the type of boost control you have).
If this valve becomes stuck, for whatever reason (dirt, rust), the turbocharger's boost pressure cannot be properly regulated.
Sure, I will.
- the ease of adjustment on the turbocharger.
- all tax hoses to the turbocharger (bends, damage from rodents).
- the aforementioned solenoid valve (which, at least in the 1.9L engines I'm familiar with, isn't that expensive).

Just use the search function a little more; you'll find many helpful posts on the topic.

Best regards, Rainer.

Hello,

@Rainer
The charging socket is at least connected with a slightly loose connection in my AKN model, and it's likely the same for Emil's V6.

@emil
For testing purposes (if they are identical), try swapping the magnetic valves of the VTG and the AGR.

The people at the Skoda workshop claim the problem comes from the auxiliary module. They say that if it's turned off, the error wouldn't occur. The problem is that I can hardly test this, because with the traffic density on our highway, I can barely reach the 210 km/h speed at which the error occurs, even without any performance boost.

Does anyone have experience with whether a device like that can cause this kind of error?

or whether I should perhaps consider going to a different Skoda workshop.

Hello Emil,

die VTG-Mechnik ist nur bis zu einer bestimmten Abgastemperatur ausgelegt. Dabei spielt das Alter des Laders keine Rolle. Die verwendeten Materialien der bewegten Teile und deren Spielpaarung sind genau abgestimmt und bieten meist nach oben nicht mehr viel Spielraum. Funktioniert die ganze Geschichte dauerhaft und problemlos serienmäßig bei 750°C, klemmt die Verstellung in der getunten Version bereits bei 780-800°C Abgastemperatur. Die renomierten Tuner nehmen hierauf Rücksicht und schaffen es durch geschickte Abstimmung von Einspritzmenge zu Ladedruck die Temperaturgrenze einzuhalten. Eine andere Möglichkeit besteht darin die Verstellkraft der Steuerdose zu erhöhen. Hier wird die serienmäßige Dose durch eine mit größerem Membrandurchmesser ersetzt und man gewinnt 20-30°C. Die wesentlichen Faktoren für die Abgastemperatur sind Einspritzmenge, Ladedruck(-temperatur) und Spritzbeginn. Je höher die Einspritzmenge, desto höher die Abgastemperatur. Bei gleicher Einspritzmenge und Erhöhung des Ladedrucks - sinkt die Abgastemperatur wieder. Je The earlier the injection starts, the lower the exhaust gas temperature.
If the auxiliary module only increased the fuel injection amount and the standard turbocharger is already operating near its maximum capacity, that could explain the higher exhaust temperature and the resulting VTG (variable turbine geometry) malfunction.

Regards,

Sepp.

Thank you for the detailed answer. That explains why the error only occurs when I've been out and about all day.

Quote:

Hello Emil, die VTG-Mechnik ist nur bis zu einer bestimmten Abgastemperatur ausgelegt. Dabei spielt das Alter des Laders keine Rolle. Die verwendeten Materialien der bewegten Teile und deren Spielpaarung sind genau abgestimmt und bieten meist nach oben nicht mehr viel Spielraum. Funktioniert die ganze Geschichte dauerhaft und problemlos serienmäßig bei 750°C, klemmt die Verstellung in der getunten Version bereits bei 780-800°C Abgastemperatur. Die renomierten Tuner nehmen hierauf Rücksicht und schaffen es durch geschickte Abstimmung von Einspritzmenge zu Ladedruck die Temperaturgrenze einzuhalten. Eine andere Möglichkeit besteht darin die Verstellkraft der Steuerdose zu erhöhen. Hier wird die serienmäßige Dose durch eine mit größerem Membrandurchmesser ersetzt und man gewinnt 20-30°C. Die wesentlichen Faktoren für die Abgastemperatur sind Einspritzmenge, Ladedruck(-temperatur) und Spritzbeginn. Je höher die Einspritzmenge, desto höher die Abgastemperatur. Bei gleicher Einspritzmenge und Erhöhung des Ladedrucks - sinkt die Abgastemperatur wieder. Je The earlier the injection starts, the lower the exhaust gas temperature. If the auxiliary module only increased the fuel injection amount and the standard turbocharger is already operating near its maximum capacity, that could explain the higher exhaust temperature and the resulting VTG (variable turbine geometry) malfunction.

Hi,

I just wanted to add that the oil temperature is also quite important.
If the oil gets too hot, which can easily happen when simply increasing the injection amount or injection duration, the turbocharger also loses this cooling. This is because the Garrett VTG turbochargers are not cooled by water, but "only" by engine oil.
This can, among other things, rapidly shorten the lifespan of the charger's bearings.
Especially during prolonged high-speed driving on the highway, the temperature can quickly rise to levels where the turbocharger's cooling system is no longer sufficient.

So, the temperature of the charger is a relatively important factor for its lifespan.
Whether it's the adjustable blades or the bearings.

Quote:

Reputable tuning specialists take this into consideration and, through skillful adjustment of fuel injection and boost pressure, manage to stay within the temperature limits.

Never. I think most people have probably never even heard of this matter!

Greetings.
Thomas.

Where can I get the larger tax disc?

Hi Emil,

It probably won't be that simple. If, unlike with AFN, a complete solution isn't readily available, you'll first need to examine the original canister and its installation environment. Since the standard canisters can't be disassembled, you can only estimate the membrane area based on their external dimensions. Furthermore, you would need to measure the (under-)pressure based on the stroke (travel) of the control rod. With this information, you could then inquire with the service centers (spare parts distributors) of turbocharger manufacturers to see if there are any canisters with a larger diameter and similar stroke/pressure characteristics available for other applications (it doesn't necessarily have to be from Garrett). The next step would be to adapt the bracket to the turbocharger. So, it's not a straightforward process. However, I mentioned this possibility because a friend of mine took this exact approach years ago to obtain the right control canister for his turbo conversion.
However, in your case, it would first be important to understand exactly what the additional device does. Perhaps your problem could be more easily addressed by slightly reducing the fuel injection amount, which would lower the exhaust gas temperatures.

Regards,

Sepp.

Okay, I should check with the tuner again to see if he's going to reduce the fuel injection amount.

Thank you again .

With the current cold weather, the problem hasn't reappeared (and I'm driving a bit more cautiously), so it's probably just a very minor issue.

I went to the tuner - he simply reduced the spring preload of the 'dose 3' by 3 turns - now the error only occurs at approximately 238 km/h.
(At approximately one rotation, the value was around 212; at two rotations, it was around 220.)
- He wants to remove another half rotation today - then the problem should be gone...
hopefully
Otherwise, another quarter needs to be cut.

I only turned it out a third of the way - so a total of 3 and 1/3 rotations.
Now it accelerates smoothly without fluctuations, reaching approximately 248 km/h according to the speedometer .
That's how it should be...