BMR Ladedruckproblem | Posts 16+

Hello,

it would be interesting to see what actually applies, such as: too small injection quantity (the turbocharger doesn't get going), not enough air...


Can you measure Lambda at full throttle at 1500-4000 rpm in 4th gear? A log that only contains air mass, fuel injection amount, and engine speed at full throttle can be used to compare whether the lambda value is correct.

Best regards, Rainer

Here is the last log.

Hi,

So, the lambda value at 4000 rpm is already too high, even with the correct boost pressure. My assumption: Closing the fuel injectors, which leads to less power and also to less drive for the turbocharger due to the even lower fuel injection amounts in reality.
This may result in a slower loading speed compared to normal.

However, the relatively low Lambda value at 1800 rpm doesn't quite fit. Maybe you have a combination of several problems.
Insufficient air at low speeds could be due to a malfunctioning AGR (Exhaust Gas Recirculation) system.

Generally regarding vacuum: Do you have a vacuum valve adjustment kit for your engine, and if so, is it properly adjusted?

Best regards, Rainer

Hello,

To the AGR: The vacuum line is sealed, so a leaking AGR valve wouldn't have been noticeable, am I mistaken?
And do you mean by AGR the electronic valve in front of the intake manifold or the one at the back, controlled via the U-pipe, located at the back near the radiator? Besides: How do they differ in their function?

Regarding Drall Valves: They are present and the U-shaped container is sealed.



Greetings

AGR = Exhaust Gas Recirculation Valve, redirects exhaust gases from the exhaust manifold (still before the turbocharger) back into the intake tract (intake port behind the throttle valve) in order to reduce NOx emissions.

Best regards, Rainer

Thank you, but that was already clear. What I meant was: There is a valve on the AGR cooler that is moved via a U-shaped housing, and another one that is electrically controlled and sits in front of the intake manifold. My question was, why there are two, and what each of them does.


Does anyone have a new idea about where the problem might be? The carbonization of the PD elements cannot be the cause, as Lambda fits in the lower area. And the AGR is demonstrably airtight.
Is it advisable to simply try to align/swap both, just for the sake of trying? I would prefer clear evidence as the basis for any actions.

So es gibt die Klappe am AGR-Kühler (Bypass), die eigentliche AGR-Klappe, die Drosselklappe und die Drallklappen.

If you have {DRALLKLAPPEN} installed, they may be either functioning or permanently open due to the lambda value at high speeds. {STELLDOSE} may also be prone to failure.

Best regards, Rainer

The valve assembly is working; it was replaced along with the intake manifold.


Best regards

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