I own an older A4 Tdi Quattro. I have noticed recently at night starting off at lights with car headlights on behiond me, a serious plume of exhaust smoke in their lights. Is it normal to have a lot of fumes out of the back of a diesel, is it only caused by the turbo when you accelerate hard, or will there always be some visible exhaust?
I have been told that one cause of this may be that there is too much fuel being seekd by the engine, or too rich a "mixture" is being used, and that Audi can tweak some buttons or something to alter the fuel or mixture if necessary to reduce the exhaust emissions. The car did pass its MOT last week, which must include emissions, so maybe it is just normal. Pain in the *** though, as everyone else knows when you have your foot to the board trying to accelerate as there is a cloud of smog blocking their view forward. Any ideas on this, or what causes it and if it can be reduced?
Cheers