LLM from DC: A Problem Solver for All Walks of Life?

Has anyone here ever replaced their VW/Bosch mass airflow sensor with one from Daimler-Chrysler/Pierburg and verified that it works properly? The reason for this thought was this thread here: http://www.motor-talk.de/time162/b2002/c07/d3/e10028/z7

Best regards, WarLord.

http://www.passatplus.de/download/LMM.htm

Oh yeah, the AVF and AXF also work!

Regards,

Manuel.

Okay, I got the part number (1Z). According to a post on defa, the mass airflow sensor from DC/Pierburg is supposed to work there as well. Does anyone know if VW only uses Bosch parts for the mass airflow sensors, or do they use other manufacturers? I haven't had any problems with my mass airflow sensor yet, but the car has only about 160,000 km on it.

Best regards, WarLord.

I also have the Pierburg installed in my car, specifically in the 115hp 1J pump-nozzle engine (AJM).
It's going great! / It's working perfectly!

To my knowledge, VW only uses components from Bosch.

Be glad that you don't have any problems yet!

@warlot

'This part doesn't fit in a 1Z engine! In the 1Z, the mass airflow sensor (MAF) is integrated into a pipe and has a completely different connector. However, this MAF sensor is also made by Piezoelectric (Pieburg)!'

Hello.

As far as I understand from various other forums, the specific DC-LMM (direct coolant low-mount manifold) is typically installed in a "larger" engine than our 1.9 TDI engines are.

This results in a larger and therefore less sensitive overall measurement range, leading to a "flatter" characteristic curve.
This, in turn, leads to the fact that most TDI engine control units report a lower air mass flow with the DC MAF sensor than is actually flowing through – similar to what would happen with a defective original MAF sensor.

Conclusion: Only if the VAG mass airflow sensor is "malfunctioning" to a greater extent than the DC mass airflow sensor's insensitivity to a working VAG mass airflow sensor, will the DC mass airflow sensor improve engine performance. However, in case of doubt, it may not reach the same level as with an original VAG mass airflow sensor (hopefully that makes sense ).

Reports in other forums describe poorer acceleration with the DC-LMM (direct cylinder liquid manifold injection) system at lower engine speeds, where the full boost pressure hasn't yet been reached and there isn't yet an excess of air available.
Initially, the high excess air at full boost pressure, combined with the lower DC-LMM value, allows for the release of the full injection quantity.

Consequently, contamination or aging of the DC-LMM will lead to a reduced fuel injection quantity and thus a loss of power, even at full boost pressure.

A possible solution could potentially involve a carefully controlled enlargement of the measurement cross-section (i.e., drilling) on the DC mass airflow sensor to approximate its characteristic curve to that of the VAG mass airflow sensor .
If one exaggerates [the measures], the soot emissions will increase, and passing the next inspection is acutely at risk.

Based on what I've read so far, the LMM (Mass Air Flow sensor) works without any problems with the 1.9 TDI engines, and according to VAG Com, it provides the same readings as the original VW/Bosch LMM. However, it is said not to work with the 2.5 TDI engine.

@joergs

I love the 1Z engine. It has a very robust motor, and now it also has a Pieburg mass airflow sensor. Was this actually installed as a permanent replacement, or did the 1Z also come with a Bosch mass airflow sensor originally? The car has almost 160,000 km on it and no problems (I just heard a small hissing sound from the engine compartment yesterday, so I'll check the intercooler hoses and cooler).

Best regards, WarLord.

@warlord

To the best of my knowledge, Pieburg parts were only used in the 1Z engine.

Regarding the DC LMM (likely referring to a Direct Current Linear Measurement Module), it seems to be generally working as intended. However, as mentioned before, lower values are being measured. This could result in an improvement being noticeable if the old LMM is faulty, as Ulf already pointed out. But when replacing a functioning LMM with the DC part, a deterioration might occur.

but that's irrelevant in your case anyway, since the parts are not compatible!

And I already have the Pieburg one installed. *g* Another thing about the DC mass airflow sensor: From what I understand (based on the link mentioned above), people who installed it have all gotten the same normal values as I did.

By the way: You mentioned that you had problems with the intercooler system in your 1Z engine. Where exactly was the problem located?

Best regards, WarLord.

WarLord wrote:

According to what I have read so far, the LMM (Mass Air Flow sensor) works without problems on 1.9 TDI engines, and according to VAG Com, it shows the same values as the original LMM from VW/Bosch. However, it is said not to work with the 2.5 TDI engine.

Hi.

I once copied a picture from another forum.
The comparison (using VAGCOM data logging) refers to a 150 hp TDI engine, which already has the highest airflow rate of all (standard) 1.9 engines and is therefore most similar to the DC donor engine.

And I already have the Pieburg in it. *g* By the way: You wrote that you had problems with the intercooler system on your 1Z. Where exactly was the problem?

Greetings, WarLord.

In my case, it was the rubber connectors on the hoses directly above the engine block. I replaced these with reinforced rubber hoses, and it's been quiet for 4 years. Additionally, I replaced the original clamps with stainless steel hose clamps. Since then, I haven't had any more problems with boost pressure!

@ Ulf, nice graphic!

The only thing that bothers me is that it's from the 'Gute Fahrt' forum! Sometimes I get the feeling that VW employees are posting there and sabotaging all the good ideas!

In the Passat3b.de forum, a similar measurement was performed, but with the result showing less air mass being measured up to 2000 RPM, and then a slightly increased air mass reading afterwards.

Unfortunately, I can't find the thread anymore; it was a while ago though!

Regards,

Manuel.

Okay, that's fine. You've convinced me. Is there any way to adjust the measurement somehow? Maybe with resistance or something? *g* By the way, is the 150 hp TDI really just a 1.9-liter engine? Which one is it then? It must be an older model, right?

Best regards, WarLord.

Caution!

My AHF (presumably a device or system) also indicates that it works, but it doesn't. There are HFMs (High-Frequency Modules) for my engine, some with separate measurement probes, and others that are "one-piece." I have the latter type installed, which means the DC (Direct Current) measurement probe is not compatible.

Best regards, Rainer.

@rainer

'It's the same with AWX. But with my AWX, the DC-LMM fits perfectly! However, as I said, with a functioning LMM, there is subjectively better performance and lower fuel consumption compared to using the DC part.'

@Manuel Thomas

Don't worry, this post is from me; I originally posted it on vw-audi-forum.de.
posted, and I am not affiliated with Volkswagen.
My car ran significantly worse with the DC-LMM than it did with the original one.
Below approximately 2000 RPM, there is very little power output, but then there's a sudden surge of power that occurs because, from that point on, the power output becomes relatively normal.