I have a 2.4 JTDM Brera and have the same puff of smoke. There are a number of threads on this subject and it could be down to a number of potential issues, some people debate oil (leaking down the valves, or in the turbo) and some debate diesel.
What was happening with mine was if the car had been standing for a while (Over night) the first start of the day would give a big puff of blue (ish) smoke which lasted for about 10 seconds then would disappear. Not too much of an issue you may say, especially when selling as clearly you would fire up the engine before. However when you have to reverse off the drive each morning back through your puff of smoke then it becomes a smelly issue in the cockpit! I've been doing regular long motorway mileage and on the basis I have had little/no reduction in oil level, I put my investigations down to fuel.
Things to initially consider, fuel treatments (valve cleaning stuff plus DPF regenerators) and also oil treatments like hydraulic valve lubricants. I did all this, worthy exercise to condition the engine but unfortunately the puff of smoke didn't go away.
The main thing I did to stop the smoke was to remove all of the Injectors. A bit fiddly having to remove the fuel pipes etc but took about an hour. They were sooted up, so gave them a good birthday (clean up) and got all of the carbon out of the grooves etc so they came up like new. I also soaked the ends in a carbon removal fluid to ensure all of the holes were clean. I was thinking about replacing them but at £200 each for a refurb I wasnt prepared to spend a grand on this! What was happening that one or two injectors weren't closing properly as carbon had got in. These injectors are like syringes , they pop open under pressure and close up again on each fire. So, as the car stood overnight enough diesel was seeping into the cylinder heads, so as it started there was excess fuel hence the burn off of smoke, plus the first few starting revs were noisy and juddery as the engine wasn't burning efficiently. Once all cleaned then to reassemble back into the car NOTE as I found out you can not reuse the seats (copper washers)at the end of the injector. These are soft and pliable which squash down under torque to make a perfect compression seal. (I had to remove them all again as everyone leaked pressure !!) so before you start the job buy a set of 5 washers (£5 on ebay £8 from dealer). Now I get no smoke and the start is quieter and smoother. PLUS the car is generally pulling harder as the revs are more responsive. Total time to do 2 hours! cost £8 , a worthy Saturday morning exercise with any Alfa diesel with a puff of smoke.
Last edited by Chillihotrodder; 28-10-13 at 15:06.