Engine Timing

[CToney]

I had a Tune-up Conducted at DSG. Along with it I had new HO injectors installed and a 16 cm turbine housing. Everything seemed ok. But when the engine was cold it would run really rough and would smoke tremendously. Lots of unburned fuel. Once warmed up it would run ok. I took it back to solve the problem, they had set the timing wrong. It ran better. But now has started to run a little rough when I throttle it up on initial startup. I would like to know a bit more about timing and how to adjust it. Also before the mods I had turned the pump up a 1/4 turn and turned it down when I got the truck back. I also turned the smoke down because it was excessive. Please help.