Gitter vor dem LMM - wozu dient es ? | Posts 32+

Okay, no. This is definitely not what PB would ever produce. First of all, the opening is square and measures 0.5 x 1.0 cm. Furthermore, the sensor plate isn't located directly in the airflow; it's recessed into a wall.

I've also noticed a bit more smoke when starting the engine recently.

'On my car, at level 1, it doesn't really smoke when the engine is hot, but it does when starting up. However, you can now see a small puff of smoke in the rearview mirror (although you mostly see it through the straight exhaust pipes).'

I need to disconnect the AGR as a countermeasure .

Hi,
"I also removed the small grille behind the channel in the mass airflow sensor (MAF) on my Passat with the 130hp PD engine, manufactured in 09/2001, and I can definitely notice a difference, especially between 1500 and 2000 rpm. The hesitation is now gone; it responds immediately to throttle input."
Not much has changed at the top, but I haven't been able to properly test it yet due to the bad weather.
Modifications: EGR valve defective, intake path open at the front crossmember, 150 Ohm temperature sensor.
Sure, here is the translation of the text from German to English:

"Hello."
Harald.

Postscript:

After removing this 'thick, approximately 45-degree plastic grid,' and having installed 'another MAF sensor,' I had to remove the metal plate from the EGR system for a warranty repair.

Therefore, I simply used a hex screw to block the tube leading to the membrane pump in a purely academic way.


Anyway, I'm now getting an error message that says 'implausible LMM signal,' and I don't know if it's caused by the loose screw or the missing grid.

The air mass at idle is now 560 mg/stroke with both measurements, which is essentially what you'd get with an 'open' mass airflow sensor, and that's probably too much even with a functioning EGR valve.

Based on the previous post, I assume that the grid can only be removed if the EGR system is deactivated. In principle, removing the grid achieves the same result as using the diode trick, or am I mistaken? The measure isn't quite as drastic. Or does the normal intake airflow actually get so negatively affected by the grid that it offers advantages compared to simply using the diode trick?

Best regards, Matthias.

matt wrote:

Based on the last post, I assume that the grid can only be removed if the EGR system is deactivated.

If you want to break your HFM faster, then yes!

Here's a small tip: The Bosch document "Application Note for Hot-Film Air Mass Sensors HFM6 in Engine Control Systems" explains the purpose of the grid.
Just so much... it has something to do with water and dirt...

Hi,

Okay, you're right. There are already enough positive comments about the grid in the thread. I might try to make the LMM (likely referring to a mass airflow sensor) more aggressive by drilling an additional hole. However, I think the diode modification seems a bit too extreme.
Best regards, Matthias.