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LLM Before Failure?

 
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Schlack



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Post03-07-2007, 11:54    Subject: LLM Before Failure? Quote

Good day everyone,

Since I'm brand new here and have already done a lot of reading, I have a question for the experts.

Here are the details: Volkswagen Golf 3, engine code AFN, 153,000 km mileage, no chip tuning installed, all filters recently replaced.

"Basically, I'm experiencing a slight hesitation or jerking between 2300 RPM and 2700 RPM under full load, and after analyzing the control logs, I see that this is where the boost pressure is being regulated. The mass airflow sensor (MAF) values also fluctuate in that range, and I suspect that these fluctuating MAF values are causing some variation in the boost pressure as well."

Based on what I've read so far, the LMM value should be around 1000 at 3000 RPM, and most importantly, it should remain constant.

I can't achieve that.

Therefore, I would appreciate it if someone here could confirm my suspicion or see something else in the log data. For me, everything else seems to be fine, but as I said, the LMM (likely meaning "low mass measurement" or similar) is low.

/viewtopic.php?p=112954#112954

Thank you very much and best regards.
Slag.
Jubi G3 GTI TDI
Spritmonitor.de


Translated on 09-08-2026, 21:31.
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Roger
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Post03-07-2007, 13:30    Subject: LLM Before Failure? Quote

It's the opposite: the load demand (LD) is controlled based on "gas pedal" input, and the motor torque (LM) then simply follows the LD.
It has been observed that the lambda (air-fuel ratio) value does not reach the target value even when the load is fully adjusted, and in some cases, the engine is operating directly within the soot map range. It is likely that individual values are even lower than what is visible in the log due to the low sampling rate.

If the intake path is (hopefully) relatively closed, I would suspect the mass airflow sensor (MAF). If you want to be absolutely sure before buying a replacement, temporarily install a diode as a fake MAF sensor. Make sure to deactivate the EGR system in this case. Warning: This may void your vehicle's approval certificate!

The original VW mass airflow sensor (MAF) has proven to be the best option. Experiments with IHBAH MAF sensors have sometimes resulted in expensive double purchases due to differing characteristics.
Gruß
Roger

MJ 2018 GTI Performance DLBA

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Translated on 09-08-2026, 21:34.
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