I don't know the car but you certainly shouldn't get black smoke from a modern diesel. Black smoke is a sign of to much fuel or not enough air so I would check the air filter first and also the MAF sensor to seeif it isn't giving false information to the ECU.

The turbo will spin practically all the time it takes very little gas flow to make it do that but it needs a lot to make it spin fast enough to give any boost.

As max torque is at 2000 rpm, i cant see how the turbo is kicking in at 2.5?

On cars before 2004, smoking exhausts was commonly due to injector problems.

I would get it in for a health check, to a tuning specialist.

In normal driving you rarely need to run over 2k revs, going through the gears.

I have the excact problem that you describe and the garage don't seem to be able to fix it. Can you tell me, did you find a solution and if so, what was it? I have had my X-Trail from new and I know for sure how well it should perform and that there is a problem, you are not expecting too much.

As already stated the first thing to look at is the EGR valve. I had exactly the same problem and fixed it cleaning the EGR valve as explained on this website

http://www.x-trail-uk.co.uk/viewtopic.php?f=50&t=4816&start=0

The job takes about 30 minutes, needs a short screwdriver to unscrew the screws to take the top off the valve housing and some solvent, like engine cleaner, and WD40 to get the valve sliding again. Website says to replace the gasket seal but I just reused the old one.

Edited by carr on 16/09/2012 at 21:54