Hello everybody! First, forgive any english mistakes. I'm not so skilled as I wish to be. :)
We have a GV 2.0 16V 1999, E37 version (latin america) that we use to tow our boat. The big problem is the fuel consumption. I've previously owned another one but V6 2.5 that didn't "drink" this much.
So, I started looking for possible problems and/or defective parts. I already own the Rhinopower SDL interface, which helped a lot solving the V6 2.5 issue, and using it on the "new" car, I think the ECU is working strangely ("fail safe mode" or limp mode?).
The O2 sensor voltage is changing, but STFT, LTFT and TFT shows only zero. The injection PW varies. Exhaust smells gasoline, which clearly indicates a rich mixture.
I've checked and changed spark plugs, cables and coils.
Any ideas? Can anyone post here the mileage you're getting on the same car? (Here we're getting 4-5km/l in transit. My 2.5 used to achieve 6-7.5 in the same situation).