Does not want to start when hot

I tried start the vehicle it will not start, I've change the fuel pump, engine censor, I've even done baick setting if it manage to start it will not hold steaming

2000 Skoda Octavia 6 cyl Front Wheel Drive Manual

my car starts then I press on the excelerator and it konks out

Engine
do not starting morning

2003 Skoda Octavia 4 cyl Two Wheel Drive Manual 198000 miles

I recentley changed the cambelt on my 1.9tdi engine which then would not start so I towed it to the local skoda dealer who have verified that the timing is ok but are now struggling to find the fault.I changed the fuel filter and glow plugs after doing the belt and prefilled the filter with diesel and cracked off the injector pipes and diesel spurts out so it seems to be injecting. The dealer has also verified that the compressions are good and that the camshaft is not broken. The only other thing that happens when cranking over the engine a lot of white smoke is omitted from the exhaust below the manifold. Any help you can give will be greatly appreciated, many thanks E.