LMM Diode: How to Draw and Understand

Hi.

Could someone please quickly sketch the diode that I need to insert into the contacts (solely for testing purposes on private property ) so that I can make the mass airflow sensor redundant?

Thank you.
m;

http://www.luxus-wg.de/~martin/auto_bilder/LMM_pierburg.jpg

Okay, I'm not very good at drawing, but it's actually quite simple:
The diode should be connected between contact 1 and contact 6, and the ring on the diode should be facing towards contact number 6.
The numbers are already included.

Best regards, Daniel.

Okay, thanks.

I just did a test run with a diode (0.7 volt drop), but with an active EGR system.

Result: The Russian border (referring to a maximum power limit) is NEVER reached, unlike when using a real LMM (Linear Mass Flow Meter) !!! Even if it's only by a small margin (the difference in torque between the maximum power setting and the "Russian border" is only 1.2 mg/H).

However, when the engine is restarted, the diode is detected as a fault.

00553 G70 implausible signal (or similar).

However, even after the EGR pressure sensor connector was disconnected, the EDC (Engine Control Unit) did not detect it, did it?

I always thought it should be the other way around: The diode shouldn't detect anything, but the pressure sensor should detect when it becomes currentless?

http://www.luxus-wg.de/~martin/auto_bilder/LMM_diode.gif

m;

@ Dieselmartin

Do you have an AHU engine?

How many mg/h of fuel does your system inject at full load?

dieselmartin wrote:

I always thought it should be the other way around: the diode shouldn't notice, but the pressure sensor notices when the current is lost????

The diode (not) noticing depends on the motor computer software - the trend is: "the newer, the more likely to notice" .

However, disconnecting the AGR (Abgasrückführung) connector is always noticeable in principle. Why it's not the case for you is a mystery to me...

@ Steffarn

I have a 1Z engine with a very old 021 AF 8-bit MSA 12 system, and it's starting to exhibit occasional misfires at 1400 RPM. It was manufactured on December 18, 1995, making it a very early MJ '96 model.


@ Ulf

It's possible that your "faulty" AGR pressure sensor isn't being detected because the mass airflow sensor (MAF) is already recognized as "faulty," since the AGR rate can't be regulated "without" a functioning MAF sensor.

I will continue to monitor the LMM and AGR pressure transducers .

m;

dieselmartin wrote:

It's possible that your "defective" AGR pressure converter isn't being recognized because the MAF sensor is already recognized as "defective," since, "without" a functioning MAF sensor, the AGR rate can't be properly regulated.

So, you're suggesting that my ancient engine control unit (ECU) is essentially thinking, "The mass airflow sensor isn't working correctly, so I don't need to display the error message that should be coming up for the EGR valve." I find that hard to believe.

More likely, the measurement error threshold for a broken valve winding is not reached -> for example, leakage current flowing in parallel with the valve winding.

For me, the crucial question would be whether you notice anything from the diode.
Regardless of any soot limits, once it's inside, it doesn't matter, as long as the car drives the same way with this "problem" as it does without it, meaning with a virtually new mass airflow sensor.

edit @dieselmartin:
Slightly off-topic, but would you possibly be able to send me a picture of your engine bay without the engine cover? I'd like to see how your injectors are positioned in the engine and how the hoses are routed. Thanks.

http://people.freenet.de/golf-schrauber/Kran_Oese.jpg

http://people.freenet.de/golf-schrauber/wasserkasten.jpg

http://www.luxus-wg.de/~martin/auto_bilder/afn_deckel/

To get "fresh" images, I would need to unscrew the cover ( ).

m;

However, when the engine is restarted, the diode is recognized as a fault.

Okay, so I've had it installed for a while now, and I haven't received any error messages!
I drive a 1996 Toledo with a 1Z engine.
I have no idea why this is only happening to you.

Best regards, Daniel.

I now know where the 00553 code comes from, in relation to the G70.

I had the ignition turned on while the MAF sensor was disconnected, and then I connected the diode.

(This allowed me to directly read the LMM replacement value of 425 mg.)

And that's what it looks like.
http://www.luxus-wg.de/~martin/auto_bilder/LMM_diode2.jpg


m;

Thank you for the pictures, they are enough for me!
But do you really notice a difference between a diode and an LMM?

@x

I'm not entirely sure about the difference, especially since my lambda sensor is only slightly weak (meaning the Russian border rarely and weakly triggers), and it makes sense to also disconnect the EGR valve when running with a diode – otherwise, it remains open constantly under partial load.

Therefore, I adjusted two parameters.

I've now tested it on approximately 400 km of highway, and there were no disadvantages.

It might be my imagination, but I think he's handling the climbs a little better (the GRA managed to get through the Hunsrück).

m;

Okay, after continuing to drive with the "defect," I'm actually becoming more and more satisfied.

I almost never use my scooter in the city anymore (I used to use it a lot because it made things much more spontaneous).

Okay, the LMM-AGR feature isn't as impressive as the box claims, but it's enough for the commute to work.

Parts for the LMM have been ordered, and then it will look clean .

m;