what is catalystic converter

[ajith]

when my car started throwing out black smoke the mechanic said that my 335i is having a catalytic converter problem

what are the other ways to confirm this as it a a very expensive issue if it this is confirmed so before that i need a second opinion on this

Regards

[shaheen]

Better get the computer diagnostic done than relying on one o two mechanic say. If it shows the computer code of Air flow meter issue than that is bad and causing this smoke by running engine on rich fuel. If exhaust code is shown or no code is shown then u can doubt cat. You can get aftermarket one much cheaper than the genuine one (if you want).