black smoke usually indicates over fueling or a fuel problem,

try this, unplug the multi plug which goes to the fuel pressure actuator, and then start it and see what happens,

i had the same problem on saturday as u have described on a mates rs turbo caterham hes been building for 3 years, he started it up and done the same as u described, i unplugged the wire i say above and it runs fine, so its proberly the fuel pressure actuator stuck over the years and over fueling it, try it and see what happens