I have a 2002 (540) BMW Alpina, recently i have noticed the check engine light was on, even if i tried to switch it off by using the BMW computer will appear again after driving 50KM, after investgation i found that the sensor of the bank 1 is not reading i changed but still the same, then they told there is a problem with Catalyser bank1, i have took both of them out waiting for the new one, the check light engine disappear but i got more smoke with smell inside the car which is not whit or black, so could you please advise?