High Boost VTG TDI: Causes & Solutions

I'm currently experiencing the following problem.
My car broke down on the highway while I was driving at full speed.
went into emergency mode.
Measurements taken with a boost pressure gauge have shown that...
The boost pressure is too high.
The maximum boost pressure of 1 bar was not reached until over 3,000 RPM.
and in fifth gear, it exceeded [the speed limit/a certain value].
Furthermore, it was observed that the loading jump...
slow increase without exaggeration or corrections.
Okay, VTG and solenoid valve checked.
VTG was common.
Okay, I bought and installed a new solenoid valve.
Now, it was possible to observe the system in detail.
One could find an overpass and a regulation.
Unfortunately, that was not the case.
Still having problems with the high boost pressure.

So, I extended the VTG shaft.
(Increased this previously due to low loading capacity.)
filmed)
The overhang was significantly smaller.
Currently, the boost pressure is still at a high level of 1.1 bar.
Previously, up to 1.5 bar.

Ich überlege das gestänge noch weiter zu verlängern. Abthen he
The maximum boost pressure is only achieved at high load and at speeds above...
2000 RPM reached.

I've already checked the hose leading to the VTG, but I couldn't find anything wrong.
determine.
I haven't made much progress with the troubleshooting articles either.
come.
Maybe one of you knows the answer.

Regards,
hturbo01

Hello,

What kind of engine do you have?

Only VAG com can tell you if this regulation works.

In a 4-cylinder engine, the duty cycle is typically set at 85% to prevent excessive pressure buildup. In a 6-cylinder engine, it's usually around 20-30%. If the pressure becomes too high, the control system will attempt to increase (for a 4-cylinder) or decrease (for a V6) the duty cycle. However, there's a limit to how much it can adjust. Eventually, the pressure will become too high, triggering the emergency mode.

If you shorten the strut, you achieve everything faster. However, you'll experience more overshoot. Either you're completely outside the operating range, or your VTG (Variable Geometry Turbine) mechanism is jammed, or the vacuum pressure acting on the valve is far too high.

I'm curious to see what happens.

Rainer.

Hello.



Unfortunately, I don't have a VAG-Com.
I cannot verify this for that reason.

I can tell that there is too low a pressure.
I can't imagine that, given the vacuum system.
Nothing has been changed.
The aspect ratio was not altered.

The only thing that has changed before is this.
VTG rod, because it should not exceed a pressure of 1 bar.
achieved.
Even with the overswing, he still achieved the desired result.
Ladedruck von 1 bar nicht erreicht. For that reason.
'This has been slightly shortened.'

What do you mean by 'completely out of the question'?

The only thing I can imagine is that the solenoid valve...
already had a defect, and the new one has...
'the whole thing can't be regulated anymore.'
Then I guess I'll just have to bite the bullet and do it all again.
accept.

The engine is a 1.9 TDI AFN with 81 kW (equipped with a large VTG turbocharger).
Factory-made).#

I had the engine chip tuned to 94 kW.

Regards,
Hturbo01

Hello there,

The control ratio is defined in a characteristic curve, and a portion of this curve can be adjusted by the control system. Both the pressure sensor and the VTG (Variable Turbine Geometry) mechanism have a specific operating range.

Control valve 0% (unplugged): Mechanical stop at full travel. 100% = Constant voltage = Mechanical stop in the opposite direction. In idle mode, the actuator is always pulled to almost its maximum position.

If you've extended the rod beyond its designated range, then at a 95% duty cycle, the end of the adjustment range is mechanically reached, and the control system cannot further reduce the pressure at full load.


The money spent on an OBD adapter is well worth it. Even the demo version of VAG Com can do quite a bit.

Good luck.
Rainer.

Hello Datsun,

I found the problem.
The tuning box was set to too high a level.
After I removed the tuning box again,
The turbocharger pressure was back to normal.

Okay:
Connect the tuning box and turn it down until...
The boost pressure is back to normal.
Of course, something will go wrong.
But there's still plenty left.
For that reason, it no longer emits smoke.


I already have an upgrade box for my tuner.
ordered (with a report) to address the load sag.
Adjust the settings to suit the tuning box.
According to the manufacturer:
Without tuning: 81 kW, 235 Nm.
D-chip: 94 kW, 275 Nm.
D-chip + Airtronic: 94 kW, 300 Nm.

What is Airtronic?

Regards,

Manuel.