Leistungsverlust im unteren Drehzahlbereich1,9 TDI-PD 130 PS | Posts 32+

The never-ending story...

See post 1 (page 1). After 28,000 km, the turbocharger was replaced as a solution to the problem of power loss at low engine speeds. The actual cause is unknown, but a suspected issue is the variable geometry turbo (VGT) adjustment (see above).

Latest update:
Mileage: 81,000 km (approximately 50,000 km since the last charger replacement). The car is currently at the dealership. It stopped working... On the highway, it only went into emergency mode. Rental car... approximately 1000 Euros, no goodwill offered.

Process:
"Since approximately 60,000 km, I've noticed a noticeable whistling sound from the turbocharger, which is audible when the engine is idling. (VAG-COM scan showed no abnormalities, all readings are within the normal range), I'm not sure if this is related to the following issue."
later Tachost.ca 75,000 km, gradually developing and progressively worsening symptoms:

-After driving uphill, the power delivery below 2000 RPM became worse.
-beim Beschleunigen u. Schalten in die Höheren Gänge traten Verzögerungen zwischen "Gas" geben und Einsetzen des Leistungsschubes ein (diese Symptome hatte auch der 1. La(the).
- Increasingly frequent power loss (limp mode) at higher RPMs during strong acceleration.
- Briefly accelerating in higher gears and within the mid-range RPM range --> limp mode.

The described symptoms primarily occurred when the turbocharger was hot, i.e., under load (e.g., during downhill driving, where there's good power delivery in the lower RPM range).

Diagnosis:
The diagnostic test revealed that when the engine is hot, the boost pressure lags behind the target value in the lower RPM range, or responds too slowly. Consequently, the power output increases with a delay corresponding to the boost pressure increase. (Diagnostic Trouble Code 11) The percentage displayed by the VTG (Variable Turbine Geometry) control valve indicates the correct target values (e.g., 28%, fully closed), but the boost pressure either doesn't increase or increases with a delay.
Autobahnfahrt, 150 Kmh , 6.Gang ,3000 Umin. , geringfügiges Gasgeben führt zu einen Ladedruckanstieg jenseits von 2800 mbar (absolut), weil VTG nicht schnell genug zurückregeln kann (Ladedruck "ist" ist kurzzeitig wesentlich höher als Ladedruck soll" und regelt sich verzögert ein, Überschwinger) auch hier regelt das Steuergerät richtig aus, 90...%, aber Reaktion erfolgt zu spät, Notlauf. Max. LadedThe pressure was previously around 2450 millibars.

On stage:
"No hard spots in the cold state. The throttle shaft is also controlled by vacuum. Basic settings are MWB 11. With the engine running, both end stops are reached. The travel distance is more than 1 cm. The vacuum pressure measured at the sensor regularly jumps from 0 to approximately -0.7 bar. The sensor membrane is in good condition."

Therapeutic attempt:
Disconnected the hose from the can and sealed it, hooked the welding wire from below onto the VTG lever, and installed the windshield wiper motor with linkage and spring.
Move the lever back and forth approximately once per second, without using any lubricants. While doing this, keep the motor running and slightly increase the throttle (approximately 3000 RPM).

Result: no change.
Today, I tried one last thing: I replaced the solenoid valve, but there's no change.
Lately, I've been constantly thinking about whether or not to overtake every truck... That's it. (Garrett turbocharger)

As I've also observed in my surroundings, this problem is becoming increasingly common (across all brands).

Sorry for the many lines, I just needed to get it off my chest. Maybe it will help someone else too, and I'd also be interested in hearing your opinions on it.

I think I'm going to get back on my old [thing].
Golf 2 TD. But my daughter won't let me have it anymore...

Here's a suggestion from me: Many problems are addressed multiple times and in various areas, which also makes searching more difficult. It might be helpful to create a system for categorizing these specific areas of focus (to better organize the topics).

Hello Hartmut,
Mine is still in the same condition as in my previous post, with 178,000 km on the clock. I occasionally experience delayed power delivery when shifting or accelerating, but it hasn't gotten worse.

cetano wrote:

Hergang: Process/Development/Origin: "Since approximately 60,000 km, I've noticed a noticeable whistling sound from the turbocharger, which is audible when the engine is idling. (VAG-COM scan showed no abnormalities, all readings are within the normal range), I'm not sure if this is related to the following issue." later Tachost.ca 75,000 km, gradually developing and progressively worsening symptoms: -After driving uphill, the power delivery below 2000 RPM became worse. -beim Beschleunigen u. Schalten in die Höheren Gänge traten Verzögerungen zwischen "Gas" geben und Einsetzen des Leistungsschubes ein (diese Symptome hatte auch der 1. La(the). Bitte gib den Text an, den du übersetzt haben möchtest. Autobahnfahrt, 150 Kmh , 6.Gang ,3000 Umin. , geringfügiges Gasgeben führt zu einen Ladedruckanstieg jenseits von 2800 mbar (absolut), weil VTG nicht schnell genug zurückregeln kann (Ladedruck "ist" ist kurzzeitig wesentlich höher als Ladedruck soll" und regelt sich verzögert ein, Überschwinger) auch hier regelt das Steuergerät richtig aus, 90...%, aber Reaktion erfolgt zu spät, Notlauf. Max. LadedThe pressure was previously around 2450 millibars. On stage: "No hard spots in the cold state. The throttle shaft is also controlled by vacuum. Basic settings are MWB 11. With the engine running, both end stops are reached. The travel distance is more than 1 cm. The vacuum pressure measured at the sensor regularly jumps from 0 to approximately -0.7 bar. The sensor membrane is in good condition." . . .

Hi,

Compliments on your focused and thorough collection of data and facts.

The symptoms suggest a classic case of a VTG hot-clamping issue.
Due to frequent load peaks that can lead to emergency shutdowns, the loader naturally operates at a significantly higher level than usual, resulting in faster wear and tear.
Therefore, that whistling might already be happening.

My suggestion:
If you keep getting faulty spark plugs ("faule Eier") from the Garrett shelf (for Golf 4 ASZ engines), try a KP39B next time (ASZ for the Polo-Ibiza-Fabia platform). It should be mechanically 1:1 interchangeable.
The software (LD input tax software) for both platforms is so similar that, in my opinion, no significant problems are to be expected.

If your engine oil is heavily contaminated, the oil temperature on the highway may increase excessively, potentially leading to exhaust temperatures that could damage the VTG (Variable Turbine Geometry) system.
While the software includes protective functions designed to reduce the LD (likely referring to a specific parameter) and the amount (presumably of a substance or quantity), I can't really assess whether they intervene early and strongly enough, especially since the parameters can vary depending on the data being processed.
Normally, the LLT (Low-Level Turbine) of the G4 ASZ increases to approximately 55K above AT (Ambient Temperature) when operating at maximum power (in the direction of Vmax). After about 30 seconds of thrust or minimal load (e.g., rolling downhill), there are still approximately 5K above AT remaining, or even less.
If it looks significantly different for you, please check the SMIC and the LD-LLT combination sensor.


Okay: If the engine has been chipped, then it might be worthwhile to consider a good software from a different tuner in the long run, as it could be more cost-effective than regularly replacing the turbocharger .

Hello ULF.

I don't think the LLt is taking on abnormal values; I looked at it with one eye, and there was nothing unusual. (Around 60-70 degrees absolute, which seems fine.)

The next loader will be different. Unfortunately, I didn't have the time, and I don't have another vehicle right now to handle it myself. I'll look into your suggestion.

Okay, about chipping. I have a tuner in my area who really wanted to chip my Golf (OBD). I told him "no" (figuratively, like "go chase squirrels").
"Nothing is coming in, no box or anything like that, just maybe an update from VAG, but there's nothing new there. (If there had been a chip installed, I would have understood...)"

cetano wrote:

höchstens ein Update von VAG , aber da gibts nix Neues.

What version of STG are you using, and what is the data version?

@Roger
I can't check right now; it's still at the . This information refers to the statement from , who checked using the VIN in the computer.
As soon as I know, I'll let you know.

@Roger
VAG No. 038906019KJ
Engine Control Unit (ECU) and Software: 1.9L 4-cylinder engine, EDC0400, part number 5256.

Hello,

Unfortunately, I haven't yet had the opportunity to test-drive a comparable TDI model, so I'm still experimenting to see how to improve the performance in the lower RPM range.

Here's a measurement diagram. Feel free to share your thoughts and opinions about it.

Best regards, Matthias.

cetano wrote:

@Roger VAG No. 038906019KJ Engine control unit and software: 1.9L R4 engine, EDC0400, part number 5256

.

"This information may be current."

matt wrote:

Please find attached a measurement diagram. You can feel free to share your thoughts on it

.
The Nm peak at 2200 rpm doesn't seem too bad, in my opinion. I would find it more informative to see a full-throttle log with the wideband oxygen sensor (MWB) readings at 8 and 11, in 5th or 6th gear, from approximately 1200 to 2500 rpm, preferably going uphill.
You can see how the LD (likely referring to a specific process or measurement) increases, and when the turbidity exceeds the rotation speed.
Normally, the target value is reached at around 1400-1500 rpm.

@Roger
Okay, thanks.

The new (replacement) turbo is installed. No more problems. Money gone... (consolation: 2-year warranty, which I might have to use again ).

@ulf
As soon as I have another person available, I will start logging the MWB data. From a quick glance, it appears that the torque limit was above the soot limit starting around 1500 RPM. Also, the boost pressure should have been at the target level from around 1500 RPM. However, I will double-check that just to be sure.
At high RPMs, the torque limit is above 50mg/H, while below 1500 RPM it's only around 40 (if I remember correctly), which is a shame because it means the 'diode trick' doesn't work as effectively as expected.
Anyway, I was surprised by the diode. For example, the response time at over 2000 RPM was almost the same as my old AZJ (2.0 85kW gasoline engine).
Nun weiß ich nicht, ob diese starke Verbesserung und auch die spürbar bessere Performance bei unter 1500 U/min am Diodentrick liegt oder an einem etwas betagten LMM. Bei dem 3000 U/min Test passen die Werte. Im LL sind es ohne AGR nur 400 statt 450-500 mg/H. Aber kaputte LMMs können ja auch träge auf Veränderungen reagieren, obwohl der 3000 U/min Test (Stationärbetrieb) i.O. ist. DumIt seems that the local dealer is not flexible enough to provide a trial version of the new LMM in order to make a concrete assessment.

Best regards, Matthias.

Hello Ulf!

Here's a log. Unfortunately, the resolution isn't as high as it could be because I had to drive in 4th gear and didn't want to exceed the maximum speed too much. I hope it's informative enough. Otherwise, I would need to conduct another test under different conditions.
I would like to know if the trends are normal.

Best regards, Matthias.

matt wrote:

Mich würde einmal interessieren, ob die Verläufe normal sind.

Well... I have a log from a standard G4 ASZ engine, running at full throttle in the highest gear, starting at 1200 rpm.
The LD (likely referring to a specific system or indicator) activates much earlier in your car compared to mine, but even on a slight incline, the engine revs up extremely slowly.

More LD (likely referring to "Low Down" torque) in the low RPM range is probably difficult to achieve with a standard ASZ engine. However, I don't know to what extent that can be a real benchmark for your longitudinally mounted engine.

That's correct. The range from 1200 to 1500 is almost 20 seconds. In my case, it was only 3 seconds. Therefore, I think it makes sense that my target LD (likely referring to a performance metric) is reached at 1500. However, I will also run another high-resolution test, possibly with the handbrake engaged. It would also be interesting to know how the other 96kW models perform in similar conditions, specifically below 1500.

Best regards, Matthias.

Hello,

Here's another update. The logs were captured at a higher gear (6th gear), resulting in a higher resolution. In particular, the LD (likely referring to a specific data point or characteristic) looks similar to the one shown in the log posted by 'die.'
I find it strange that the LMM (Linear Mixing Ratio) dropped at 2000 min^-1, as you can clearly see in the first xls file.
This log might also explain the poor starting performance. For example, an ASV that I examined had a LL value of 490, not 400, like mine. As soon as I have another mass airflow sensor (MAF) to test, I will also provide data on that.

Best regards, Matthias.