BMW X Models Engine Problems

Your fuel consumption is way off the claimed consumption figures released by BMW. The company claims the X3 20i should get on average 7.3L/100km, 6.2L/100km on the highway, and 9.2L/100km in city driving. You have to allow for some variation on those numbers due to individual driving conditions, but to be so far out suggests there is something wrong with your car. I wouldn't expect it to reduce enough to get even close to those numbers simply by driving it. Have it checked by your BMW dealer.

Yes, I agree, it is unreasonable. Take it to a BMW specialist, like John Heckrath at Heckrath Engineering in Melbourne and he will be able to reset the computer for you. BMW change the oil on the basis of engine hours run, not kilometers driven, and the computer needs to be reset to start the clock ticking towards the next change.

We haven't had any experience with the chip you refer to, but have had some with other chips that have been offered here in the past. Yes they can work, but they do so by taking the engine calibration closer to the edge than the carmaker would dare do with safety. In my view they would clearly affect the warranty.

The BMW dealer is the best placed to work out what’s causing your problem. If you’re concerned about the potential cost of his work ask for a quote and make a decision based on that. You could place a time limit, of say, three hours on him and ask for a report at the end of that time so you can decide on what you then want to do. Without knowing the cause of the problem before you start it’s hard to say how long the investigation might take.