Marcos Maniacs

This really baffles me.....

Engine starts fine, run it 5 minutes it won't restart for 30 min, the 
radiator isn't even warm.....Run it into work (20 miles @ 30 minutes) 
and it won't start for 2 hours or more)..This has been tested, 
verified and confirmed time and time again.

Checked after the 5 minute run for spark (shocked the hell out of me 
won't do that again).  Opened the AFM flapper slightly and could hear 
the pump run and the fuel return back to the tank.  Cleaned 
temperature sensors into manifold (they had a slight build up of 
scum).

Everything seems to be perfect.  

I have not tested to see if my fuel pressure somehow drops after 
start up.  I don't know what would cause this, 5 minutes of pump 
running in cool fuel shouldn't degrade the discharge pressure let 
alone make the delay longer after longer running.  I have sprayed 
starter fluid (hated to do this....) and the motor came to life 
briefly.  What I expect is that the spray injectors are not being 
sent a signal to open.  Is there a relay (temperature sensitive) that 
prevents fuel injection if some interlock function is enabled?

Does anyone know the logic in the firing of the injectors, such as 
fuel pressure (no pressure switch appears to be a part of the 
sequence)water temperature high limit?? keeping the injectors from 
working.  I know that the AFM does interlock with the fuel pump and 
may likely enable the injectors to fire.

I am still thinking that it may be the electronic magneto or the 
remote amplifier but that doesn't account for the fact that starter 
fluid worked.....

That's the tale.  Help??