I have a V50D with (I assume) a Peugeot XD3P engine. It starts and runs well but emits lots of black smoke when revved. It also feels like it is losing power due to this issue. The previous owner (a friend of mine) had the pump and injectors overhauled. Could it be a timing issue ? Or the pump needs some other adjustment? The only number on the ID plate looks like : 9RB862. Based in the UK.

Any help appreciated.