lmm fake | Posts 16+

joergs wrote:

nimmt man noch die konvertierung und umrechnung und was auch immer dazu denke ich, daß man real vielleich bei etwa 6-8 je sekunde landen könnte ! das denke ich mal sollte reichen. oder ?

Hi Jörg,

Based on my gut feeling, I would say "yes."

Since the tumble generator primarily acts as a soot reducer, its most important application for rapid responses occurs during rapid acceleration, when boost pressure increases.

If the amount of fuel injected doesn't reach its maximum potential due to a slow sampling rate of the LMM (which doesn't convert the increasing boost pressure into air mass values quickly enough), the engine will definitely not produce excessive soot - it will simply lose some acceleration power.

And when the boost pressure drops rapidly, the anti-lag system is usually already active anyway, so in my opinion, it doesn't really make a difference.

Hi Jörg,

Based on my gut feeling, I would say 'yes.'

Since the tumble generator primarily acts as a soot reducer, its most important application for rapid responses occurs during rapid acceleration, when boost pressure increases.

If the amount of fuel injected doesn't reach its maximum potential due to a slow sampling rate of the LMM (which doesn't convert the increasing boost pressure into air mass values quickly enough), the engine will definitely not produce excessive soot - it will only result in slightly reduced acceleration.

Und bei schnell fallendem Ladedruck ist gewöhnlich eh die Schubabschaltung aktiv, da machts IMO also garnix.

Okay, at least we can agree on that point for now!

I'm finally getting an evaluation board for the Atmel AVR microcontrollers, and theoretically also a general-purpose communication adapter. I should be able to start experimenting with them as early as next week!

Starting on Monday, things should hopefully become calmer. That's when my new job starts, far away from home. Hopefully, the long, lonely evenings will help me to be more productive!

@gremlin

Are you sure that the formula is correct?
Let's assume everything is running in idle mode.

Engine displacement: 1900ccm = 1.9 liters.
speed = 830 RPM = 13.83 RPS
Air density: 1.87 g/l.
lodeddruck = 0 bar

wenn ich das jetzt in deine annahme einsetze und den ladedruck weglasse, dann komme ich zwar auf g/s als einheit. aber der wert der luftmasse ist nur etwa 1/5 des vom stg berechneten. nehm ich bei ner beliebigen drehzahl noch den ladedruck hinzu paßt auch die einheit nicht mehr !

I'm sorry, but I can't translate that because it only contains question marks. Please provide some actual text for me to translate.
That works perfectly.

1900ccm results in 475ccm per intake stroke.
1 liter of air has a mass of 1.29 grams at a pressure of 1013 millibars (and approximately 20°C).
This would then result in 612.75 mg per injection, ideally.
Assuming a generous delivery rate of 0.8, this equates to 490.2 mg per injection.
approaching the idle range (good delivery rate) with a faulty EGR valve .
If calculated with full pressure, you can expect approximately 980 mg per injection.
So, that fits...

The only inaccuracy is the delivery rate. In the case of the turbo, it also depends on the boost pressure. But it doesn't have to be that accurate since it's just a simulation...
Theoretically, it should be sufficient to use the boost pressure as a reference value. However, since the mass airflow sensor (MAF) measures in milligrams per unit of time, the engine speed must also be taken into account.
The total air mass increases with increasing engine speed, while the air mass per intake stroke should ideally remain constant in a naturally aspirated engine.
The engine speed and boost pressure are directly in the wiring harness (the engine speed signal goes to the instrument cluster!). Therefore, it could even work without CAN.

CU Gremlin.

@gremlin

Okay, that also makes sense. I hadn't necessarily paid attention to the delivery rate! And I calculated it with the 830 RPM! Of course, then it works out. If I follow Michael II's motor target values, in measurement group 3, the air mass at idle is specified as somewhere between 200 and 400 mg/stroke. But wouldn't that imply a different delivery rate? If we were to assume a lower delivery rate of, say, 0.5, then the air mass at full throttle would no longer be correct! (612.75mg * 0.5 = 306.xx mg, which is about 600 mg/stroke). What happens if the fake reading in idle provides a significantly higher air mass value? (It's roughly double what the system specifies!) Or how can...? Can the delivery rate be represented as a function of boost pressure?

Maybe I'm just being too critical about everything?

What happens if the mass airflow sensor (MAF) provides a significantly inflated air mass reading while idling? (It's roughly double the value specified by the engine control unit!)


This can lead to an error entry due to implausible LMM signal readings.


or how can the delivery rate be represented as a function of boost pressure?


by running an intact engine and recording the measured values, which are then logged .

'By the way, Michael's measured values refer to an engine with a functioning EGR system. Consequently, the fresh air mass flow rates are significantly lower than the purely calculated values because exhaust gases are being recirculated. If the EGR system fails, the mass airflow sensor (MAF) readings will get much closer to the theoretical calculations.'
'The problem with using a fake EGR valve is that you have to disconnect it. If the EGR valve is working correctly, it won't run properly. Because if you simply adjust the cylinder filling without considering the EGR valve, the mass airflow sensor (MAF) reading will be too high, causing the EGR valve to open fully. Then the engine will sound like a Russian tank, or it might stall immediately.'

CU Gremlin.

So, after several weeks, the time has come, and I've started measuring voltages using the AVR microcontroller.

nach etlichen stunden verarsche bin ich nun endlich dem compiler auf die schliche gekommen und festgestellt, daß er nen hau hat !

Okay, so right now I have an MPX4250A lying around on my desk and I'm using it to measure the ambient pressure. It should also work in a proper setup. One sensor would be for the ambient pressure, and the other for the boost pressure.

Now I have a huge problem: My Passat is at home, and I can't really get access to some things. Could someone please post the wiring diagram for the pressure sensor (the external one in the intake manifold, not the one built into the ECU), and its characteristic curve? Or is the characteristic curve identical to that of the MPX4250?
Okay, next problem: where's the best place to connect the tachometer? I would be very grateful if you could help me, as it would allow me to prepare quite a bit for this weekend!

Hello Jörg's,

nächstes problem, wo zapfen wir am besten den drehzahlgeber an ? wenn ihr mir helfen könntet wäre ich sehr dankbar und könnte für das we schon einiges vorbereiten !

How about connecting directly to the control unit's connector? All the signals needed for your project are available there. The connectors can be opened without damaging anything, and you could proactively tap into any additional signals that might be needed later. Furthermore, the fake mass airflow sensor (MAF) could be relatively inconspicuous, hidden somewhere inside the water tank.

Is there a wiring diagram available anywhere?????

Okay, so it seems like VW is now considering and perhaps wants to set more affordable prices for the LMM. What do you think: Is this 'fake' still interesting, or is it better not to invest any more time in it?! What are your thoughts!?

Hi Joergs,

The question is, what constitutes a dead mass airflow sensor (MAF). Isn't it more likely that the values simply get worse, but still react to changes? A completely dead MAF would more likely be the result of broken wires or complete contamination, rather than what causes the 'death' of most MAFs.


'Since last night, I've had a failure. Regardless of the load, the LMM (lambda measurement module) signal voltage is always just above 1V. This unit hasn't been performing at its peak values under full load for some time now, but it was still generally working! However, suddenly, it completely failed.'

joergs wrote:

seit heute nacht habe ich einen toten. egal welcher belastungszustand immer knapp über 1v lmm-signalspannung. das teil hatte schon länger unter vollast nicht mehr die top-werte, ging aber insgesamt noch ! aber mit einem schlag hat sichs jetzt mit der herrlichkeit !

Hi Jörg,

I assume you're talking about your LLM?
Just out of curiosity: How old is this item, and how many miles/kilometers has it been driven?

@ulf

Yes, it's mine! Unfortunately! I can't say how old the car is because I've only had it for about three-quarters of a year. I've driven it since around 30,000 km. For the next 4-6 weeks, it will be a research object, and then I'll test the new customer service policy again. Yesterday, I experienced an issue. I didn't know it was so acute, as there were only occasional hiccups and a slight lack of air mass in the upper load/RPM range!

@ulf

Now, someone from DC is working on my Passat! The Mercedes people couldn't believe that it would work. It was quite a sight when I took out the tools and installed the part right there.
Take it as a replacement, and after I finish my 'research,' and Volkswagen's act of goodwill, an original one will again do its job! }

@joergs

Could you please record the characteristic curve of the DC LMM using VAG-Com, and ideally also include the original characteristic curve for comparison?

So far, I'm still missing that final, definitive comparison of the DC and VW mass airflow sensors. I haven't been able to find anything useful about it online yet.

Thank you in advance.

Thomas K. wrote:

Could you please record the characteristic curve of the DC-LMM using VAG-Com, and ideally also include the original characteristic curve for comparison? So far, I'm still missing that final, definitive comparison of the DC and VW mass airflow sensors. I haven't been able to find anything useful about it online yet.

If you search for "" somewhere "on the internet," you won't find much, but here .

or :wink:here

Could you please record the characteristic curve of the DC-LMM using VAG-Com, and ideally also include the original characteristic curve for comparison?

So far, I'm still missing that final, definitive comparison of the DC and VW mass airflow sensors. I haven't been able to find anything useful about it online yet.


If you search for '' somewhere 'on the internet,' you won't find much, but here .

or :wink:here


Yes, yes, I understand about the specifications! But there's definitely a difference between €71.49 and €250 or €300. And since, as far as I know, due to the new customer service policy, I'm getting a replacement, but the defective one is a good demo and test object for the fake product, I think this solution was quick and acceptable!
'Besides at low speeds, I didn't subjectively notice any difference earlier. Also, for daily commuting, it should definitely be sufficient! The old one broke down near Frankfurt/Main with a car full of passengers! It was quite an ordeal. Unfortunately, the diode replacement didn't really work well!'