For D jet info, have a look at Porsche 914 sites.

The cold start inj only operates at very low temps ( 30* F ? ) and is wired to a thermo time switch. If someone rewired things it might act differently.

Cranking 2x in a row should be enough to shut the cold inj off. Unplug the wire and see if you still get start / stall.

Check for power at the ignition coil in the run position. Also, D jet needs to see a coolant temp signal otherwise it won't operate.