lmm fake | Posts 32+

joergs wrote:

...ja ja ist mir klar mit der kennlinie !

Hello Jörg,

The answer was not for you, but for Thomas, who had asked about the different characteristic curves for the DC and VW mass airflow sensors.

@Bertil

Thank you for your quick help .

'But I've seen that curve before. In the 'Gute-Fahrt' forum, I think there was a discussion about whether the mass airflow sensor (MAF) from the ARL (150PS TDI) is the same as the 'standard' MAF used in engines like the AFN, AJM, etc., because the part numbers are different. Also, the curve of the ARL MAF seems very high compared to mine (AJM).'

Unfortunately, I can't record a characteristic curve; I can only obtain individual values with the small, portable VAG tester.


@joergs
I didn't mean it should be done immediately, but rather when you have time again, and if you were able to get it at a discounted price from the original source. I don't want to pressure anyone into doing anything .

Thomas K. wrote:

... Im Gute-Fahrt-Forum wurde aber glaub ich darüber diskutiert ob der LMM vom ARL (150PS TDI) der gleiche ist wie der "Allerwelts-LMM" in z.B. AFN, AJM usw., da die Teilenummer ja unterschiedlich ist. Außerdem sieht mir der Verlauf vom ARL-LMM sehr hoch aus im Vergleich zu meinem AJM.

Well, at least for me, the values are also that high.
The 81kW VP TDI engine (engine code??) from my brother's SEAT runs perfectly with my mass airflow sensor, but it delivers slightly lower peak values.
I'm not entirely sure about the differences in the mass airflow sensors (MAF) used by Volkswagen... but there probably aren't many.

...ja ja ist mir klar mit der kennlinie !

Hello Jörg,

die Antwort war nicht für dich sondern für Thomas der nach den Unterschiedlichen Kennlinien für den DC und den VW LMM gefragt hatte.

war mir klar !!!! ich wollte nur nochmals die beweggründe meiner entscheidung erläutern, da es sicherlich bald wieder erhobene zeigefinger geben wird !!!!

@thomas
I'll do it as soon as I have a moment!

@everyone
According to AKTE, there are two different VW part numbers for my AWX engine: one ending in the letter 'A' and another ending in the letter 'B'. However, according to reliable sources, they both refer to the same Bosch part number. Is this possible? What is the difference then?

hello,

Okay, it's finally here – the fake [device] had its rollout today. It had been working in individual parts on my desk for a while now, but only there. The processing of the speed sensor signal was one major hurdle, and deriving the mass airflow-voltage equation from the few data points in the datasheet was another. Actually, both were quite a pain. But the rollout brought reconciliation. So far, it's working great. However, it still has a couple of issues. First, I selected the characteristic curve for the wrong mass airflow sensor. I'll correct that tomorrow. Second, for some reason, the calculation of the mass airflow voltage sometimes produces a negative value. In those cases, I simply set that voltage to zero.'Hmmmm, and that can lead to temporary malfunctions in the short term due to reduced fuel injection! But I think these are probably just teething problems and perhaps minor issues. I hope I can quickly go through the logs and find the cause of the error. For now, though, I'm very happy with the result.'

For those interested in the technical details:
microcontroller: AT90S8535 (the AT4433 should also be sufficient, but I consciously chose the larger one because it offers more I/O pins for potential extensions. Furthermore, the ATMega8 and ATMega16 should also work).
D/A converter: AD569 (thanks, gremlin). I'm only using the 8 most significant bits. I plan to try Philips' DAC08 types soon. They don't have a Vout but an Iout, but we should be able to work with that.
Then there's an oscillator (KF351) to convert the signal from the speed sensor into a nice square wave, a 7812, a 7805, and an ICL7662 to generate -12V for the D/A converter and the oscillator. Also, a few capacitors, a quartz crystal, and that should be it!

If everything goes as I imagine it will, the fake [item/person] will have its first outing on Sunday.

Hello Jörg's.

How's your emulation going?

Sincerely,


Sepp.