1.4 TSI CAVD Power Loss

Hello everyone,
I have a problem with my Golf V Variant 1.4TSI (CAVD), which is the turbocharged engine with 160 horsepower, just like the one used in the Golf 6. Mileage: 91,000 km

Symptoms:
- Power loss or lack of torque
- DSG downshifts significantly -> likely due to the engine. I'm driving a D7 Tempomat 110 uphill, and the DSG, for example, downshifts to 5. I can then manually shift up to 7th gear and then use the foot pedal for minimal acceleration -> Reverse gear is unnecessary (according to my opinion)
- Wave-like Acceleration:
I drive on city streets, covering a long distance uphill, with the cruise control set to 60 km/h and the gear shifted manually. Then you notice how the compressor engages ("quietsch" ), the car accelerates, then slows down, then accelerates again. -> Hypothesis: The charger is not delivering power, is the SUV defective?

Now there was once a mistake entry, Rainer has already written something about it: /viewtopic.php?t=28362

Verified:
- Loading system, no leaks detected
- The wastegate can be opened with the pump, the pressure seems to be okay.
- No misfires or incorrect ignition timing were observed.
- The SUV valve has been replaced: Rattling during gear shift, but more power is present, with the remaining symptoms still present. The gear shift is now better, and the vehicle no longer reverses during braking in gear –> The Wastgate mounting appears to be slightly worn, and it may also be sticking in the hot state? But could the rattling be normal, as the SUV needs to open in gear? Perhaps it is defective? With the old one, it's all sorted.
- Loading Pressure Log (short log when picking up my daughter):
The charging pressure builds up somewhat slowly, while the operating pressure is always at a minimum of 960 mbar. This seems completely illogical, why does the target pressure drop to 400 mbar? According to VCDS, the engine load can reach 160%. What is the purpose of this figure? Software should be original.

Where would you advise me to proceed? I'm planning to replace spark plugs and coils. The spark plugs would need to be replaced during the next service, and the coils are also prone to failing here. Should I replace the N75, which is the turbocharger control valve? Should I consider buying a new SUV? And regarding the turbocharger, what experiences do you have with how sensitive it is, especially regarding the wastegate valve? Adding a new charger just because of the valve storage is somehow not cool

Thank you in advance.

Best regards,
Christoph

Hello Christoph,

"The problem might be with the SUV. The charging pressure regulation works perfectly at the beginning in the log, but not at second 249."
It is conceivable that it hangs sporadically.

Why the loaded pressure is below the ambient air pressure... I hope the application engineers thought about this, probably a loaded pressure below ambient air pressure is simply ignored.

Quote:

The engine load, according to VCDS, can reach up to 160%

What appears as "motor load" in the log is actually an internal load factor, which does not equal 100% under full throttle. The value is of no significance without a precise understanding of the underlying dataset.

Best regards, Rainer

Hello Rainer,
thanks for the explanations, they sound plausible, even though I wonder why someone would do something like that. But this often also stems from time pressure, etc.

The measurements at second 249 perfectly match the behavior that the engine always briefly stalls as long as the compressor is active.

With "clamping SUVs" do you mean that they have a door that remains slightly open? However, this new SUV hasn't brought any improvements, I think we can therefore exclude it.

Also, the pressure build-up initially works, but not anymore after the switch is turned on. SUV should, however, remain closed throughout the entire process, or?

Oh yes, I was also considering the possibility that the valves might have too many deposits and are not closing properly. There's also the BEDI cleaning service.
Has anyone here perhaps already had experience with this?

Best regards

Hi,

Quote:

With "clamping SUVs" do you mean that they have a door that remains slightly open? However, this new SUV hasn't brought any improvements, I think we can probably rule that out.

possibly. Was a genuine part installed? How about the electrical cables/connectors for control?

Quote:

Also, the pressure build-up initially works, but not anymore after the switch is turned on. SUV should, however, remain constantly closed during the process, right?

Good question, I don't have that car. Are there any data blocks in the engine control unit where you can see the control signals?

Quote:

Also, ich habe auch darüber nachgedacht, ob die Ventile vielleicht zu viele Ablagerungen haben und deshalb nicht mehr richtig schließen. There is also the BEDI cleaning service. Has anyone here had any experience with this before?

Unfortunately, in that case, a compression test might be useful, or perhaps examining the intake manifold with an endoscope.

Best regards, Rainer

Hello

Here's just a thought, as I came across it recently and maybe it could help you find a solution.

My colleague had a G6 Kombi with exactly the same engine, manual transmission, and similar problems with power and torque losses.
He had clogged intake channels, and as a result of the poor purging/turbulence, the fuel injectors were also clogged.

Short trips should be avoided. The vehicle was used for approximately 20% off-road and 80% on the highway at an average speed of 120 km/h over a distance of 40 km.
This was within the vehicle's warranty period at 78,000 km. The head was removed.
Channels cleaned and injectors replaced. He also received a software update for that, and then everything was quiet.

Maybe, try removing and inspecting the injector, and also inspect the intake channels.



Greetings, Mpire

TDI-Driver1 wrote:

There's also the BEDI cleaning service. Has anyone here perhaps already had experience with this? VG

Yes. I own the device and have had only positive experiences with Lambda's products.

My urgent advice: before you start randomly swapping parts, I recommend first performing a bed cleaning. Then you have a good basis for further troubleshooting, if it still exists.

Hi,

The CAVD is the motor that is frequently targeted by attacks near the bridge piers.

Was about checking the compression?
Has he ever stalled or hesitated at idle or low engine speed?
MIL been there?

Has the action 24S4 been carried out?

Hello everyone,
Thank you for the extensive input. Let's try to answer all the questions.

Quote:

Quote: With "clamping SUVs" do you mean that they have a door that remains slightly open? However, this new SUV hasn't brought any improvements, I think we can therefore exclude it. possibly. Was a genuine part installed? What about the electrical cables/connectors for control?

It's not from VW, but it's also used by VW, namely Pierburg, so yes. The cables and connectors are okay, although I'm not sure if the valve opens as intended during the "push-to-open" operation. Regarding... MWB, I need to check this at first glance, no, I'm still checking.

Compression test is on the list, I need to get an adapter.
I have pressure sensors that I can use for this.

An endoscope is also available; I should check how well the intake manifold can be removed. "Perhaps I can also investigate the issues related to the suction tube pressure sensor, etc., and take a closer look at them."

@Mpire:
You also confirm that the Schmoder can cause problems. I would naturally prefer not to replace the injectors just for cost reasons. The driving profile is not ideal; my wife uses it for everyday activities, such as shopping and taking the children to school. While there has been some driving on country roads, there are no highways. Standheizung ensures that the engine is at least quickly preheated (auxiliary heater is also activated).

@vag-driver:
What device do you own, a professional one or a DIY kit? If it's the latter, I wouldn't have a problem buying one. The next question would be whether to verschandeln it before use or during the ride. There are conflicting opinions on this. Do you happen to come from Lower Bavaria?

Quote:

The CAVD is the motor that is frequently targeted by attacks near the bridge piers. Was about checking the compression? Has he ever stalled or hesitated at idle or low engine speed? MIL been there? Has the action 24S4 been carried out?

Yes, unfortunately, I hope it's not missing. Compression is on the to-do list, no more jerking, MIL (Malfunction Indicator Lamp) triggered once during the Italian vacation, then never again. The 24S4 was already performed in late 2011.

Hello, how are you?
Christoph

I am from Hesse and own the device developed by Walter Stephan. The number of VW workshops offering this type of cleaning is increasing. I recommend that you contact a BEDI partner.

Hello,
Regarding {BEDI Reinigung}, I have now found a provider; it's about a quarter of an hour's drive away, costing around €180-€200. However, I am considering whether a DIY kit from Turbosprayer might also be a good option, as the cleaning needs to be carried out regularly. Does anyone have any experience with that?

I removed the intake manifold pressure sensor (G71) and the intake air temperature sensor (G42) from the intake manifold. As shown in many videos, this sensor was noticeably dirty (see pictures). I also used the endoscope through the opening to try and see something, but it was difficult because it reflected a lot, which suggests the presence of an oil fog.

Unfortunately, I haven't been able to see the valves due to the engine without disassembly.

Additionally, I removed the spark plug from cylinder 4; the picture was fine for me. However, the thread was damaged, and there were also some light brown crumbs in the cylinder head and on the piston (the spark plug made a loud squeaking noise when removed, engine completely cold). What could this be and what caused it? I then removed it with a vacuum cleaner.

Further, I reinstalled the new (suspected defective) SUV. I had the clattering noise (likely from the wastegate) before. My theory was that it wasn't opening during the boost operation. However, I checked the logs, and there was no indication of excessive pressure. The clattering was no longer reproducible. Perhaps applying copper paste to the wastegate flap (temporarily) helped. I've attached the logs again; they look good, and the car ran smoothly. Perhaps cleaning the intake manifold sensor was also beneficial. However, the DSG still shifts very early. Initially, Logfahrt followed the same route, but the oscillation of the boost pressure due to necessary compressor adjustments did not occur this time.
Hello, how are you?

PS Interesting article about these engines and their problems (hope it's okay if I link externally, otherwise please delete):
http://www.seatcupra.net/forums/showthread.php?p=4474688#post4474688

BEDI Reinigung is TÜV certified. I am not familiar with the Turbo Sprayer system.
Essentially, the initial cleaning consists of the basic cleaning and the long-term cleaning. First, the tank line is disconnected, and instead of gasoline, the engine runs with the cleaning fluid. Then, the fluid is sprayed through the air intake hose, and the warm engine is revved up to 4000 to 5000 RPM. Finally, add one more can to the tank and, if possible, use the fuel to completely empty the tank at a moderate speed.