A little help!
We run a Renault Master Van 2006 ( i think - its on a private plate) 2.5 Dci .
Recently it has started chucking out _clouds_ of black smoke on revving, it's fine day to day, and gently driving it doesn't provoke it smoking, however say for instance when going up a hill with a decent load it will smoke heavily, as will moderate revving in neutral at a stand. When revved in neutral at a stand it leaves large black soot patches on the floor!
It is not just crap in the exhaust as i have tried driving it like it has been stolen all day and it has not made a difference.
It is not down on power, sounds fine and power consumption seems usual, it is used daily in all sort of conditions. Since developing these symptoms it has been serviced, filters changed etc, nor is it throwing up any faults lights.
Any offers?
Am i correct in thinking black smoke = over fuelling / insufficient air?