Diode Trick: Works with AHU Units Too?

Is the diode trick (for LMM) also possible on a Passat with an AHU engine?

Yes, it's definitely possible!

However, this also provides the search function, as the AHU is identical to the 1Z.

Hmm okay, so an AHU is like a 1Z.
Please provide a link and pictures of an AHU mass airflow sensor (MAF) with modifications.
Is that a Pierburg?
I apologize for my German; I am a beginner and from the Netherlands.
'Thanks anyway.'

No, I don't have either of those. However, you might be able to find them using the search function.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

Yes.

AHU is a 1Z engine and they both have the Pierburg component.

I'll upload the pictures when my server is back online.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Okay, thank you for your information...

http://www.luxus-wg.de/~martin/auto_bilder/LMM_pierburg.jpg

http://www.luxus-wg.de/~martin/auto_bilder/LMM/Dsc02450.jpg
http://www.luxus-wg.de/~martin/auto_bilder/LMM/Version1.0.jpg
http://www.luxus-wg.de/~martin/auto_bilder/LMM/Version_0.1.jpg

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

m; ...

Thank you for these pictures.
Sure, here are a few more questions...
Does the complete LMM (likely referring to 'Lernmanagementsystem' or Learning Management System) also include this?
Only the diode was fixed.
Can I also take the snow screen?
Currently, my MAF (Mass Air Flow) sensor reading is 847.9 in the VAG-COM diagnostic tool. Is this value likely to increase?
Thanks, a Dutch newbie .

I'm sorry, I don't quite understand what you're asking.
Sure, here's the translation:

"Please provide only the translation, no explanations. Feel free to write it in English, as that might be easier."

I'm going back to using the original mass airflow sensor.

During the diode test, I didn't change anything on the mass airflow sensor (MAF), but it remained electrically dead while still being physically present.

"Are you seeing the same 847 mg/H maximum value at all engine speeds?"

The value drops significantly above 3000 RPM, and the fuel injection amount is reduced (column K shows the minimum).

"Das ist ein sehr interessantes Thema, und ich würde gerne mehr darüber erfahren."

I'm now running the car with the original sensor again.
I didn't replace the airflow sensor.
While testing with the diode, the airflow sensor remained in its original position; it was simply disconnected from the electrical circuit.

847 mg/h is the maximum value you can achieve. However, do you have this value for all engine speeds?

My actual performance decreases above 3000 rpm, and the amount of fuel being injected is reduced. (Column K represents the minimum value.)

http://www.luxus-wg.de/~martin/auto_bilder/LMM_defekt.jpg

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hehe.

Sure, here's the translation:

'I'm sorry for my terrible German.'

Okay, let's try having this conversation in English...
'What I really want to know is, if you installed the diode, did you completely remove the LMM (likely referring to a Mass Air Flow sensor)?'
And replace it with a different tube (I think it will improve the airflow...).
Is it possible to remove the snow screen from the LMM (to improve airflow)?

I'm driving around in a '97 Passat that has a custom-built power box, you can find more information on this website: [website address].
http://tditech.tk/ sorry but it is in Dutch.
I am very pleased with it.
But I want to try to increase the airflow into the engine.
Perhaps a larger ram-air intake.
My measured mass airflow (MAF) reading is consistently 847.9, from approximately 1600 RPM to approximately 3700 RPM.
What I understand is whether this is the maximum value for the ECU.

Thanks for your help.
a Dutch beginner.

You don't need more air .

The EDC is designed to handle a maximum load of 847 mg per revolution.

I have already done so and will not remove the sensor - the car has to look like an ordinary one .

If your engine control unit requires more airflow, you should attempt to modify the manifold pressure sensor (similar to a "cant" adjustment) to send a signal indicating a pressure that is approximately 0.1 bar higher than the actual pressure.

But don't attempt this without a boost gauge!

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Okay, that's clear to me.
It's not really necessary for me to remove the LMM (Mass Air Flow sensor) and bypass the ECU (Engine Control Unit) with a diode at this time.
'As I said, my actual MAF reading is 847.9, which seems like a new one to me... (It's 7 years old now).'
And what about removing the snow screen...?
I don't know anyone who has experience repairing or replacing the manifold pressure sensor.
Is there some information on this site that I will need to use for a search in a minute?
Thanks for your replies.

Hello everyone.

I installed an AFN tune and drove around with the diode modification, and I think the car feels less restrictive, especially with the boost controller turned up. There also seems to be less soot coming out of the exhaust.

'I don't know if the diode is causing this effect, or if it's related to the K&N filter with the fully open MAF tube (without the screen and sensor).'

http://www.home.zonnet.nl/leeoscar/images/lmm/LMM4.jpg

I'm considering using the map sensor signal and connecting it to the output pin of the MAF (Mass Air Flow) sensor.

The idea is that the amount of substance being injected will decrease when the pressure drops, making it slightly safer, similar to how a diode works.

I don't know if anyone has tried this before and how the signals compare...

And my car looks like an ordinary one under the hood...

Except for the completely removed EGR system..

Luc.

Hello Martin,

Is it then possible to increase the mass airflow through the OBD interface, for example?
from a maximum value of 847 ---> to any higher value?
'I know a guy who has a Passat AHU engine (tuned with a chip) and is currently running a MAF sensor from around 1998, calibrated to approximately 980 mg/stroke.'
Do you really need another ECU right now?
And is it possible to remove the snow screen?

'Thanks.' or 'Thank you.'

If your Electronic Data Core (EDC) is currently running with a maximum limit of 847, you will not be able to increase this limit through any means.

If you know anyone with an AHU engine and a 980 mg injector, please check the maximum amount they're injecting. I think their EDC (Engine Control Unit) won't allow them to inject more than yours. Otherwise, they wouldn't be able to achieve the typical 90 horsepower output from that engine (more diesel fuel leads to more power).

I believe the Air Flow Meter (AFM) was originally manufactured using Pierburg air flow sensors, and later switched to Bosch sensors. Perhaps the differing readings (not exceeding 1250 mg/stroke) are a consequence of this change.

Don't worry about the 847 value; if you use a box, that value is not relevant because your box will change the injection quantity anyway .

I'm not sure if removing the screen will have any positive impact on the actual airflow.

Did you disable/deactivate your EGR (Exhaust Gas Recirculation)?

If not, this would be a much more effective way to gain a bit more power (or spontaneity) – instructions on how to do this are described in German in many threads here.

"Search -> Close AGR (Exhaust Gas Recirculation)"

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Martin.

Thanks for your reply. My EGR valve is closed, and even the catalytic converter is empty.
'If I had a spare LMM, I would try it. However, if you've already removed the snow screen from an LMM like mine, it can be difficult to reattach it.'
I was hoping someone with experience using it in an AHU could provide some information.
As you can see in the picture of Luc's LMM, his snow screen has been removed, and he is happy with that.
But he has a different type of LMM (Bosch) and engine (AFN).
Thanks again.