Chrysler Repair: Diesel Voyager intermittant smoking, diesel mechanic, leakage test

Question
QUESTION: Vehicle smokes generally when cold but sometimes when warm. It sometimes does not smoke at all and is fine.  I have checked compressions, number 1 cylinder is 22 bar whilst 2 3 4 are 30 bar +, I have done a cylinder leakage test which is inconclusive. When the vehicle is smoking cracking off number 1 injector pipe stops the smoking instantly, have changed injectors but it still does the same on number 1.  Have you any idea what this could be?

ANSWER: Hi Phil,
what color is the smoke: white, black, or gray?
Which size (L) is the engine, and is it petrol or diesel?
Thanks for more details.
Roland

---------- FOLLOW-UP ----------

QUESTION: Hi Roland,

The smoke is gray and it is a 2.5 diesel manual.

Thanks

Phil

Answer
Hi Phil,
I have virtually no experience with diesel but I would suspect it has to do with the compression being lower on that cylinder. But what are the possible causes I would have to defer to a diesel mechanic. For the diesel ignition to occur it does have to reach a certain minimum of compression and you may have lost it on that cylinder.
Roland