BMR Loading Pressure Issue

Hello,
As can be seen in the title, I have a certain problem with my Passat in the lower RPM range. This issue has actually been around for a while, and I've essentially read most of the relevant threads from various forums, as I've been researching the cause since yesterday.

**Historical Background:**
The symptom of the lack of power appeared after the friend's mechanic replaced the differential pressure sensor, after I had experienced a limp mode due to what was suspected to be a full DPF (at that time, I had absolutely no knowledge of the matter). The problem is permanent and not sporadic. The workshop denied any fault and stated that no changes were made to the MSG software, which I had checked at another friend's workshop in the vehicle's history, which is why I currently suspect a randomly occurring fault or a problem related to the DPF.
All of this happened almost a year ago, and I'm only now really able to deal with it, because it's "just" a cosmetic issue, but it's incredibly annoying, and I want to be able to drive the car like I did when I first got it.

The intermittent interruption is constantly subjective. However, in the summer, I regularly received error message P0299 "Low boost pressure", but I am not sure if this is also related to the temperatures. "However, the motor's temperature dependence is well-known."
Performance at higher RPMs is not a problem; the maximum speed is achieved as before.


What I have done so far:
- Intake manifold replaced (minimal improvement, but insignificant) -> Sealed, intake air passage sealed
- Log des Differenzdrucks (weil der Sensor wurde ja ausgetauscht) -> 700 mbar. In dem Thread mit den Referenzwerten sind die größten Werte nur leicht über 400, ist der Gegendruck zu hoch? According to a voice from a forum, this should only affect it at higher speeds.
-> Logged loading pressure at nominal value
- Vacuum system checked for leaks -> Leak-proof, even when control elements are operated
- Log during manual adjustment of the VTG controller (not blocked, smooth operation) -> delta of only 40mbar at 1600 min^-1, isn't that too low? I think I once read that there should be a certain difference between being completely open and completely closed, somewhere around 1400, but I don't remember the exact value.
What's also interesting about this: The sensor value of the actuator always returns to 85% after a few seconds when it's brought to its end positions, even though the actuator isn't being moved. That can't be normal, or is there a reason for it?
- Lambda Log. Thought: If the fuel pressure sensor fails, then there should be too little fuel being injected... I just don't know what's normal and what isn't, and I couldn't find any target values.

Otherwise:
The turbocharger shaft is smooth and has no excessive play. Air filter is new.
No difference in the problem, whether freshly regenerated or not. Aschewert is 6.4 out of 60, but I suspect there was a previous manipulation because it doesn't match the mileage.
Vehicle: Passat BMR, 6-speed manual, 220mm, VIN: EZ02/08, owned since 09/18


I hope the logs are okay and allow for a proper assessment. Is something missing?
Thank you in advance.


Best regards
Phillip

700mbar is significantly too high.
You are already exceeding the usual maximum of 300mbar at 2,000rpm.

Check if there might be a blockage in the air line. Maybe try a different sensor + hose. (A detached hose behind the DPF could also cause higher readings.)

Probably, it will likely come down to the DPF. Maybe check out Rainer's cleaning instructions and consider trying to replicate them.

How is the Passat's mileage?

Greetings
Guste

Hoses are all done.

The second sensor is currently unavailable.

I've mostly read negative reviews about washing dishes with water, but I'm going to try it anyway.

Is at 220tkm


Best regards

/viewtopic.php?t=24243

Most people are unable to understand that greasy, sticky mud cannot be washed away with water.
But these are the same ones who want to "burn" the ash in the DPF or dissolve it with miracle products.

Therefore, as long as it is still possible, a forced regeneration is carried out, during which the DPF is directly removed at the end. And don't just wander around the area until another Russian shift arrives...

Will I try next, thank you


But is the behavior of the vacuum gauge in the under-pressure chamber normal?

Hello

Quote:

What's also interesting about this: The sensor value of the actuator always returns to 85% after a few seconds when it's brought to its end positions, even though the actuator isn't being moved. Can this really be normal, or is there a reason for this?

"These moments" actually say nothing, but the specific load condition of the motor.

If you feel that your engine has suddenly "lost power," it's important to remember that the DPF (Diesel Particulate Filter) doesn't fill up overnight. I would definitely recommend checking the engine's vacuum hose.
All cans (chargers, possibly (e.g., check valves, etc.) must be sealed in every position, as well as the hoses themselves.
Also, also auch Schläuche auf Mardengrab prüfen und falls vorhanden, die Stelldose für die Drallklappen unbedingt prüfen.

LG

Hello Phillip,

Have you stored anything in the fault memory, or is the engine warning light currently on? I couldn't quite grasp your comment. (You mentioned that you had the "low pressure" error in the summer, is that still the case, or is the error code no longer present?)

Perhaps the problem lies somewhere completely different.
Basically, you should first check the vacuum hoses. That can quickly become a problem to identify.

Otherwise, another piece of advice I would like to give is to check the air mass flow meter. If this is the problem, then the vehicle will also not shift properly, and it is not necessarily necessary to have an error code stored.

Basically, a forced regeneration of the DPF would be beneficial (since you already had problems with it), as if the DPF is clogged, your turbo is probably also going to fail soon.

Good morning,

Quizbot wrote:

Hello Quote: What's also interesting about this: The sensor value of the actuator always returns to 85% after a few seconds when it's brought to its end positions, even though the actuator isn't being moved. Can this really be normal, or is there a reason for this? "These moments" actually say nothing, but the specific load condition of the motor.

The sensor, or rather the VCDS, provides a position reading for the actuator that does not correspond to the actual value. How could this be related to the motor's load condition?


In every case:
I agree that this is probably not the cause, especially since it appeared suddenly. It will eventually be full, but anyway.

Just checked again and the underpressure system, including all junction boxes (tested with direct supply to the boxes), had no pressure loss, even after the engine was turned off.

Sorry for the confusion, the "loading pressure error" would sometimes occur in the summer, but it would eventually resolve itself after being turned off and on again. Currently, there are no errors in the memory.
I had also suspected LMM, but I thought I had ruled it out through the boost pressure measurement, as seen in the second log, where it would have to be something related to the turbocharger. Am I understanding this correctly?

I will regenerate the DPF on Saturday and then I will re-log the DDS, but I don't expect much from it. The normal regeneration process usually works fine.


Best regards

If the DPF is sealed, that means you have a correspondingly high exhaust backpressure. Your log showed that the pure DPF differential pressure was already 700 mbar. This means the engine is having a hard time getting rid of its exhaust gases. "As a result, the exhaust gas turbine lacks drive mass flow and cannot build up boost pressure."
The air mass is missing because there is no boost pressure.

The underlying cause of this problem is a clogged DPF. Regeneration converts soot into dry ash. However, the ash remains in the DPF.

Therefore, regenerate the DPF (drive gently at a warm temperature and then perform a manual regeneration while stationary), so that only dry ash remains. Then, remove it without further driving and rinse out the ash. While doing so, also check for any other damage to the DPF that may be causing the back pressure. With the wire test in the technical article, you can roughly compare the ash loading before/after, and thus estimate the success.

Then, reinstall it and everything should be fine, if it was just due to overcharging.

PS: Surprisingly, the car doesn't throw an error at 700mbar.

Greetings
Guste, who did this on the 140PS Passat (BMP) about five years ago.

I have read articles, and I will try.

Thank you in advance.



Best regards

Okay, let's create a short log with the target loading pressure, actual loading pressure, and the VTG position...

Logs attached, all measurements are the same.

Hello,

The differential pressure in the DPF seems to be much too high, which explains the lagging actual load pressure.

Rest wurde schon geschrieben.

Hi, Rainer

Good evening,
I have applied the hair mask. DDS is now at ~400mbar; still not ideal, I know, but definitely better than before.
Unfortunately, the action has not changed the symptoms.

Please find attached two logs. Apologies for the inclusion of other, unnecessary measurements.



Best regards,
Phillip Graf

Hello Phillip,

The pressure difference at the DPF is still relatively large, but since there have been no changes in driving behavior, something else must be malfunctioning.

Can you also log the engine speed, lambda value from the sensor in the DPF, injection quantity and turbocharger pressure (actual/target)?

That would at least allow us to see if the values are plausible with respect to each other. Not that the AGR doesn't close properly or that there isn't enough fuel passing through the nozzles.

Oh, no, just saw:

Quote:

03G 906 018 EM ADVMB R4 2.0l PPD1.2 G 1881

Some of these engines have a problem with injector clogging, which causes the holes in the injectors to become blocked, resulting in insufficient fuel being injected.

Please review:
/viewtopic.php?t=21429

Quote:

Hi, PPD elements with carbon buildup issues should be cleaned at a Lambda value of 1.40 or higher. Yours are only slightly below that. In the affected engines with PPD elements, the nozzle holes are coated, which prevents sufficient fuel from entering the cylinders during injection. The lambda value describes the ratio of air to fuel compared to a stoichiometric (all fuel molecules are completely burned with the oxygen in the combustion air) mixture. /viewtopic.php?t=26448 If the lambda value is high, it means there is little fuel relative to the combustion air. Here are the values you found for your engine: approximately 1.28 to 1.35 at full load in 4th gear. "It's best to click around yourself or use the search function, there's still a lot more to find on this topic." If you have a Lambda of 1.36 and "new/clean" is 1.32, then you have already lost around 3% in performance, which is about 5 horsepower at 170PS. Typically, smaller or clogged nozzle holes have a greater impact at higher speeds, compared to lower speeds, which could plausibly result in a reduced final speed.

/viewtopic.php?t=29083

Best regards, Rainer

Hello Rainer,
I have another log here with the desired values, but it's from before the washing process. I will repeat the measurement tomorrow if necessary.
I have often read about the possibility of carbon buildup, but only in connection with P_max or v_max problems, as you also write in the other thread. And that wouldn't really explain the lagging boost pressure, would it?
Nevertheless, I wanted to remove the PPDn anyway for sealing, because I was constantly having diesel in my oil.


Best regards,
Phillip Graf