This isn't going to be an ignition problem.
Sounds mostly like your start mixture isn't rich enough.
"Cold start valve" is confusing terminology because you have to have two things happen
-an air bypass to create a faster idle (better term is idle control valve)
-a richer mixture
These are accomplished by two different processes, and if the richer mixture isn't happening, the air bypass makes it worse. You can't do without, of course, when the mixture is right, so don't spend much time analyzing the "cold start valve."
Besides of course looking for not-supposed-to-happen vacuum leaks, investigate if cold start *injector* is working. This is not the same component as the air bypass. IIRC the L-jetronic systems mostly just increase injection pulse time to create the richer mixture, but on this K-jetronic system there's a 7th injector to do this. It can go bad and so can the components that make it work, i.e. temp sensors, wiring harness, cpu, etc.
Clearly foot is off throttle during start attempts. No more air needed. But, if you really think it's flooding, then give it some throttle opening while cranking. It's a great test.
Normal fuel injectors should be in good shape in any event, but any "weeping" from them may actually prove helpful toward creating the required richer mixture. This weeping is usually only problematical for hot starts. The loss of retained fuel pressure caused by this is quickly corrected when fuel pumps work properly.
May also want to read:
CIS K Warm-Up Regulator