Boost Overpressure Up to 1.7 Bar (LDA)

Hello,

"I installed an LDA unit the other day (there's a good guide here on the forum). Now, when I accelerate quickly, the pressure suddenly and rapidly increases to around 1.7 bar and then drops back down to 1.1 bar."

Is this normal? Or should I be concerned? (LMM replaced; VGT vanes are free-moving; EGR valve is defective).

He walks like "Schmitt's cat."

Thank you for your support.

Quite high. Please check it using VAG-COM and post the logs here.

Thank you very much!

I just ordered the equipment. Once I have it, I'll try it out. What information should I log during the process?

tsfreak wrote:

I just ordered the equipment. Once I have it, I'll try it out. What should be logged during that process?

1. MWB 11 mit durchgehend Vollgas von ~ 1200 bis 4500 rpm im 3., besser im 4. Gang.

2. MWB 11 with overshoots caused by "great" provocation (driving profile irrelevant).

3. Run the engine (MWB 3 and 11) for a few minutes on a country road, varying the RPMs and load from idle to full throttle, ideally with some overshoots.

Then we'll see what happens next...

Hello,

Okay, I'm ready now. I've created the logs as instructed and they are located at:

http://www.webspace-invasion.com/jst/Logs/LOG-01-011-xxx-xxx_4.Gang.CSV
http://www.webspace-invasion.com/jst/Logs/LOG-01-011-xxx-xxx_4.Gang.xls

http://www.webspace-invasion.com/jst/Logs/LOG-02-011-xxx-xxx_provoziert.CSV
http://www.webspace-invasion.com/jst/Logs/LOG-02-011-xxx-xxx_provoziert.xls

http://www.webspace-invasion.com/jst/Logs/LOG-01-011-003-xxxLandstrasse.xls
http://www.webspace-invasion.com/jst/Logs/LOG-01-011-003-xxx_Landstrasse.CSV


Please provide the German text you would like me to translate into English. I will then give you only the translation, without any explanations. Also, please specify if you want both the original CSV and a sorted Excel version of the translated text.

I hope you can view and use these files as intended. If not, please let me know briefly.

And one more thing. Based on my own experience, I've come to the conclusion that my AJM engine has quite a high fuel consumption. It only becomes bearable when the outside temperature is above 15°C. With normal driving style, it's around 6.4 liters per 100 kilometers. Otherwise, I'm getting about 6.9 liters. And just to clarify, I'm not a young speed demon (45 years old).


Thank you for your assistance!

I suspect the issue stems from mechanical regulatory problems.

a) Difficult-to-operate VTG (possibly only as a "hot clamping" device).

b) Worn-out valve tappets with excessive clearance between the rocker arms and valves.

c) Partially defective solenoid valve (try swapping it with the EGR solenoid valve).

Thank you very much, Ulf.

"That doesn't sound very good. A few weeks ago, I already proactively checked and oiled the linkage to make sure it was moving freely. A colleague with a 110hp PD engine had a stuck linkage. I'll try again when it's hot."

How can I possibly check option b)?

c) Are those the white and black ones?

Hello and good day.

I have already checked quite a few things.

For part C), I wasn't sure about it, so I haven't checked it yet.

B) I cannot assess that in this way.

I once connected the LDA between the valve and the can. It shows a pressure of -0.6 bar there. However, I noticed that if I disconnect the hose to the VGT and suck on it (with my mouth), the linkage moves to the MAX position. But it becomes relatively stiff in the last third. Now, looking at my logs – both the ones I had previously and the new ones I've created and viewed graphically – I see that the actual LDA value always lags behind and then overshoots the target.

Also würde ich jetzt mal das Ventil ausschließen. Ohe?

Or is it normal for the required vacuum pressure to increase as I approach the end of the adjustment range? That would also make sense somehow.

Could someone please help me here?

Thank you very much!

tsfreak wrote:

Or is it normal for the required vacuum pressure to increase as I get closer to the end of the adjustment range? That would also make some sense.

That's right – it makes sense, as you probably already suspect.

Hello and thank you very much, Ulf!

However, that still doesn't solve my problem with the overshoots.
What else can I do to get closer to the truth?
Could a misalignment of the VTG rod be the issue? Perhaps turning it slightly longer? I'm not sure if anything was adjusted previously. My thought is that if the resistance is too high in the last section, the overall setup might not be meeting the requirements. A slightly longer rod should improve that. Or, as you mentioned in your article, would that reduce the LD (light delivery) too much?

I also read and implemented your article about controlling and adjusting the Northwest (NW) valve. I was able to slightly adjust the shaft. Then, I turned it a bit towards an earlier timing. And sure enough, the dip up to 1800/2000 rpm and the subsequent boost disappeared. Instead, it now stays consistent from around 1600 rpm all the way up.

tsfreak wrote:

Could a misadjustment of the VTG rod be a possible solution? Perhaps try turning it slightly longer? I can't say whether anything was done to it previously. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. That should be better with a slightly longer rod. Or will that reduce the LD, as you wrote in your article?

You can definitely try it out. If the LDL level drops too low as a result, just adjust the dosage back until you find the lowest dose that still works effectively with minimal side effects.

Quote:

My idea is that if the dough in the last part is too thick, it hinders the overall development of the recipe.

If the rod of the extended (or detached from the loader-side VTG lever) container moves precisely at its tip without any jamming or catching, then you can rule out this possibility.

Quote:

If the rod of the extended (or detached from the loader-side VTG lever) container moves precisely at its tip without any clamping or hooking, then one can rule out something like that.

Hello,
A comparison of the frequency of use in cold versus hot weather conditions would be insightful. (Hot clamp)