sproket has it right, I think. Part of the start derichment is the closing of some of the spray nozzle holes when the fuel pressure gets high enough to actuate the nozzle. This kind of action adds to the detailed start scheduling that takes place in the fuel control, where, as rotormatic has said, the fuel control maintains a ratio of compressor discharge pressure (Pc) to fuel flow (Wf) as a function of gas generator speed (Ng). The carefully sculpted relationship of these three values keeps the engine from stalling, going lean hot, or stagnating during the start. This same set of measurements governs the accel and decel while the engine is running. The engineers call it the "Woof-PeeCee" ratio.
The bleed valve comes into the picture further up, where the accel from idle to power range needs stall protection, and even then, only in low temp situations (for the C30).
All this claptrap is a running advert for FADEC.