BMR Ladedruckproblem | Posts 24+

Hello,
I couldn't derive any specific actionable recommendations from the recent posts, as the suspects were consistently ruled out directly.
What do you advise? Just try to verschandeln the PDE with a trial?

Greetings

phgraf wrote:

Hello, I couldn't derive any specific actionable recommendations from the recent posts, as the suspects were consistently ruled out directly. What do you advise? Just try to verschandeln the PDE with a trial? Greetings

Yes, Lambda under full load says exactly that, according to the testing instructions. I still believe that there must be another problem.
But one after another...

I am currently in the process of replacing a part and realized that I made a mistake. Instead of the original part, 03G198051D, I have the B variant (see image). Both were equally listed in the parts catalog.

Can I still use them? If so, what is the O-ring included for? It's too big to fit anywhere on the bolt.

Hello,
The injection components are now clean. Here's the log with lambda value.
There is still no improvement in the underlying symptoms.

Greetings
Phillip

Hi,

Lambda now looks good, at least you can now exclude the PD elements.

When the load pressure builds up slowly, you need to apply more force again. I'll just start writing down things that come to mind, and you decide what might be true and what might not.

- Data set in the control unit is strange (failed/inappropriate chip tuning, e.g., incorrect VTG control).
- Leak in the vacuum system. I would replace all vacuum hoses, inspect all connection nipples for cracks and breaks, and check whether the corresponding vacuum membranes are also airtight in different positions, not just in the resting position.
- VTG lever loose/misaligned or container loose/misaligned position?
- The {Tandempumpe} also generates sufficient vacuum even at idle, and not only at 2500 rpm?

If you perform a test with a VTG clamping device, the clamping force must be applied and released in significantly less than 1 second. Adjustable lever total travel approximately 1 cm.
If the VTG rod moves more slowly, do you have too little vacuum or a vacuum leak?

If the travel range of the actuator rod is, for example, only 5mm instead of 1cm, there may be a defect in the VTG (Variable Turbine Geometry) mechanism of the turbocharger. If the travel range is suspicious, remove the air pressure cylinder on the charger. The lever for the loader must be able to move very easily, and due to the weight of the lever/container, it should fall downwards naturally.

Best regards, Rainer

Hello,
I only had time now to try a little.
I connected the pressure gauge during the drive once, and the pressure remained stable. I had already ruled out a leak in the vacuum system for quite some time.
I can also confirm the other points, except for the tax device, but I had nothing to do with that.

I'm also not sure if the problem is really due to the boost pressure, because the lack of torque is also present at engine speeds where the turbo is not yet functioning properly.
So ist der Motor beim Anfahren deutlich leichter zu stoppen, als zuvor, bevor das Problem auftrat. Upon re-reading the thread, I realized that I didn't convey my message effectively, and I apologize for that.
Can this be used to potentially identify other sources?


Greetings

If the control unit indicates that the full injection quantity is being delivered, while the lambda value is too high, see the cleaning recommendation, then the injectors are either clogged or are not being adequately supplied with fuel.

Best regards, Rainer

Makes sense. However, the Lambdawert is now appropriate.
Therefore, I don't know what I should check or try next. Can you give me some new tips, please?


Best regards

Hello,

Below 2000rpm, the lambda value is significantly higher than it should be. This is illogical.
Possible cause is poor fuel supply to the PD elements in that operating range (e.g., a small leak in the feed-return circuit) or, for example, a corrupted data set in the engine control unit.

Does the engine run within the specified RPM range with a limited fuel injection due to haze? Should he.

Intake size for fuel injection volume limitation due to haze is either the measured air mass value or the prevailing boost pressure. Suspect a limitation in the control unit regarding the charging pressure, perhaps the vacuum system is simply leaking, and the charger only builds up pressure later than it could?

Best regards, Rainer

Hello,
finally had the time and money to measure the pressure of the tandem pump (after another PPD element had failed), in order to:

dieselschrauber wrote:

Possible cause is poor fuel supply to the PD elements in that speed range (e.g., small leak in the forward/return circuit)

to rule out.
Result: 11 bar at 4000 1/min, Target value: 7.5 bar. For lower speeds, there is no specific RepLeitfaden.

Only as information... a log from a BMR after professional DPF cleaning.

Everything else is already written.

It took a while to finally get around to doing it, but now the DPF is new.
Resultat: No change in the problem. Low performance at low RPM and a boost pressure error around 2000 RPM under load.

Current Status: Fuel injectors inspected and two replaced a few months ago, intake manifold checked again today, intake valves are ok, and there is minimal play in the bearings, VTG rods are clear. I would be happy to re-press the underpressure system, but it was also sealed recently.

I'm planning to do another log flight tomorrow, but I don't really think the values will change much.


I'm really at a loss and therefore, I would really appreciate some more input. Should I try a different engine control unit?



Best regards

Here is the measurement.

4 years... ok...

Why don't you just check if the VTG is properly secured?
There is indeed a setting for the load control regulation that puts it in a completely on/off state. Then you can see if the shovels are being pulled in correctly.

Pressing the vacuum system with overpressure is also not a good idea... it can have different effects depending on the leak.

Just observe how the VTG switches from "on" to "off" in the basic settings mode, and possibly also measure the vacuum if it takes longer than 0.5 seconds to switch to the "on" position.

dieselschrauber wrote:

4 years... ok...

One always had either no time or no money

"Von Auf/Zu" still remains faster than 0.5 seconds. Here is the translation:

{TEXT}
Don't you see in the log that the value of "Position - Load Pressure Adjuster" has reached its maximum (over a long period and regardless of speed), yet the load pressure is not increasing?

Shouldn't I be asking myself why the charging pressure control is still adjusting, even though there is a significant difference in the control? I'm just assuming that it's a closed-loop control system. If not, the question is of course irrelevant.


With a vacuum system, I mean to press with a vacuum. So, "pull out". No loss can be determined.

Check the vacuum level, as there are often leaks in other components or valves that only intermittently cause the vacuum level to drop.

This regulation is not just a simple regulation; it works with pre-control. It estimates the charging pressure at time x and then controls the VTG accordingly beforehand. The pneumatic control of the VTG and the speed adjustment of the turbine are relatively slow, therefore so.