Adaptation Function: Does it work with MFA?

Hello everyone,

Regarding the adaptation channels, I have the following new questions based on my own observations.

Injection quantity.

Reducing the 5-digit value via VAGCOM at idle causes the displayed injection quantity to increase (in my case, from a maximum of 4.2 to 6 mg/stroke). The idle speed remains constant, as does the display of the rail pressure sensor voltage.
Apparently, with adaptation, only the relationship between RWG voltage and injection quantity is shifted (which is essentially the same as shifting the control mechanism on the pump ).

Under full load, the situation might reverse: A lower target fuel quantity is associated with a lower RWG voltage; a lower RWG voltage means less deflection of the actuator, and therefore a smaller actual fuel injection quantity.

To achieve the maximum possible full load amount, it seems to me that the adaptation value should be increased to its maximum limit. In my car, there is a margin of as much as 0.4 mg in idle at the factory setting, which is about 1% of the full load amount. Therefore, it would be "extremely" worthwhile to do so...

@Michael II:
Your description in the error database regarding adjusting the fuel injection amount (reducing the value results in a higher amount) seems a bit unclear, especially concerning the "interesting" full-load amount. Therefore, I suggest a change, but I don't want to jump the gun.


2. Air mass.
When the engine is idling, the target amount changes during adaptation, which is regulated by the EGR valve. When the EGR valve is temporarily disabled (for testing purposes), the actual amount does not change by adjusting the adaptation value.

According to this, it seems that channel 3 is not used to adjust the LMM-voltage ratio (interpreted as air mass), but rather to control the EGR rate... ?


3. Please correct the MFA.
According to the fuel pump, many cars consume more fuel than indicated by the average display on the vehicle's onboard computer.
Can this be corrected through an adaptation channel?

Specifically, I need the procedure for a 2001 Seat Ibiza (ALH engine) and a 2000 Skoda Octavia with 110 horsepower (engine code unknown).
Does anyone here know any details?

Hello Ulf,

ulf wrote:

... 2. Air mass. When the engine is idling, the target amount changes during adaptation, which is regulated by the EGR valve. When the EGR valve is temporarily disabled (for testing purposes), the actual amount does not change by adjusting the adaptation value. According to this, it seems that channel 3 likely doesn't adjust the LMM-voltage ratio (interpreted as air mass), but rather controls the EGR rate... ?

I agree. A forum member's experience supports this, as I advised them to simply adjust the target value downwards through adaptation when they were getting too low LMM (mass airflow) readings.
According to his statement, this had no effect on the reduced performance caused by the defective/dirty mass airflow sensor.
I haven't yet tested whether increasing the target mass airflow rate (LMM) not only affects the EGR rate but also reduces the fuel injection volume.

Best regards, Rainer.