Smoking at speed

On way home in overdrive (dont know how fast as speedo isnt accurate) but quickish and had black smoke,eased off accelerator and it stopped. any ideas or was i just going to fast in the old girl? its due M.O.T on 13th so im sending it into a localish landy bloke to get it M.O.T ready and do few gaskets to minimise the oil left on my drive so may mention it to him.dont want to be getting sky high bills from engine rebuild though.lol.
cheers

Hi mate is it a petrol or a diesel, either way black smoke will be excess fuel so I wouldn't worry too much especially at wot

Diesel.sorry.heart just sank a bit as only got it in december.
cheers

It may be that it was the diesel engines first good run for a while, they do tend to throw a load of muck out when wound up for bit after being "Gently" driven.

If its flat out I wouldn't worry, they tend to over fuel and kick black smoke lease above first blast in a while will kick out plenty of carbon deposits

I had a 110 diesel that used to kick out black smoke all the time at speed had it for about 5 years

Cheers all. Prob the fastest its had been since iv had it. also i did put some of that additive last time i filled up thats meant to clean injectors so that could make sense i guess.
cheers