I bought a 78 280z a while back, it ran excellent until it started smoking and running rich when i step on the gas its black smoke but when its ideling its like a white or blue. Tt runs fine when its warmed up. Ive checked the injectors, changed the thermotime switch and how would i know if the cold start valve in stuck open? oil also shoots out when i take the oil cap off, could it be sticky valves?

Disconnect the harness from the cold start valve. I doubt it's stuck open - sounds like you're running WAY rich, more than the dribble from the CSV would provide, I'd think.

The cam is flinging oil around the inside of the valve cover, so I'm not surprised you have oil coming out when you take the cap off.

How much oil does this car use normally? Is it visibly leaking? Sounds like blowby and oil burning, as well as some coolant, perhaps.