Kann Fehler nicht finden! AJM - Welcher Aufnehmer spinnt? | Posts 32+

Beany wrote:

- In my opinion, a declining (or fluctuating) LMM (lambda-controlled mass measurement) cannot be responsible for increased fuel consumption - or does the efficiency deteriorate so drastically when running very lean?

"Drastic" is subjective... If the engine is supposed to deliver a certain amount of power with a severely faulty mass airflow sensor (MAF), the required amount of boost will only be released at a significantly higher pressure.
-> The turbocharger creates higher exhaust backpressure -> Overall efficiency decreases.

There are some reports suggesting that the fuel consumption dropped significantly (10% or more, if I recall correctly) after installing a new mass airflow sensor.

Fuel consumption on the way home, with an outside temperature of 23 degrees Celsius, at a speed of 140 km/h (cruise control).
Only 6 liters!
Okay, here's the translation:

"I don't understand that at all! I even turned on the air conditioning for half the journey, and it barely made a difference to the fuel consumption!"
I actually prefer the warmth, but the car?????

Hello!
During test drives, I noticed that my MFA (Multifunction Display) reading is inaccurate when the engine is at operating temperature.
and goes up to 24.7L with 100% pedal position! But shouldn't that only happen during the warm-up phase?

During test drives, I noticed that my MFA (Multifunction Display) reading is inaccurate when the engine is at operating temperature.
and with 100% pedal position, it goes up to 24.7L! But shouldn't that only happen during the warm-up phase??

Only 24.7 liters?

So, in various more modern PD TDIs, you often see fuel consumption figures of 30 liters or more.

Best regards, Göttmann.

In the FIS (on-board computer) for the 2.0 TDI BKD engine, values in the 'END' range appear during acceleration... although only briefly...

So, the increased consumption issue has been resolved!
The thermostat was at fault! It opened at 81 degrees, which was probably too cool for the engine!
"New chip installed, now it only reaches 90 km/h and already uses 1 liter of diesel less per 100 km!!!!"

messknecht wrote:

During test drives, I noticed that my MFA display shows 24.7L when the engine is at operating temperature and the accelerator pedal is fully depressed! Shouldn't that only happen during the warm-up phase??

1. The fuel consumption for 100 km depends, among other things, on the gear being used (and the overall gear ratio). Therefore, without specifying the gear, all the information provided is meaningless.

2. The actual maximum values (around 1900 rpm for TDIs) are rarely displayed by the MFA because the engine usually runs through several hundred rpm during a measurement interval.

-> The values are most likely comparable when the engine is in its highest gear and operating within the range of its maximum torque, approximately 1800-2000 rpm. It's best to use this when going uphill, so that the engine speed increases as slowly as possible.

Quote:

So, the increased consumption has been resolved!!!! The thermostat was at fault! It opened at 81 degrees, which was probably too cool for the engine! New [thing], now opens at only 90 degrees, and already 1 liter of diesel less per 100 km!!!!

Was the old thermostat defective, or was the wrong one installed (part number)?

Please avoid using excessive exclamation points in the future (-> it can be perceived as unprofessional).

Hello Ulf!
I promise to do better!
The thermostat was defective.
However, I couldn't find anywhere that stated when it was allowed to open.
I didn't want to waste half the water just to see that it reached 81 degrees.
May open.
Please provide another tip!
How do I upload images or files here?
In my new forum section on engine technology, links are not allowed.
THANK YOU!