david carment was asking about the firing of the injectors on the AFC
injection in 1980-1983 air-cooled buses. this is what the VW Service
manual, Vanagon/Type II Fuel Systems, #WSP 521 148 00, says:

Fuel Injectors
A.F.C. fuel injectors are electronically controlled on/off valves. A solenoid
actuates a needle valve allowing fuel to be forced through the injector
nozzle. ***> All four injectors open at the same time and inject fuel
directly into the intake manifold near the intake valve. Injection quantity
is controlled by the amount of time the injectors stay open. Injector opening
time is regulated by the E.C.U., based on inputs from the various engine
sensors.
...
The control unit opens/closes the injectors by controlling the ground circuit.
...
AFC injectors used on air-cooled engines produced up to 1983 ARE NOT
interchangeable with Digijet/Digifant injectors.
-------------------------------------------------

and, from Mitchell's Electronic Fuel Injection, Troubleshooting Guide, is
this possibility:

Engine Cranks, but will not start Hot:
- Check for flooded condition, and leaking or faulty injectors.
- Test auxiliary air valve.
- Check for vacuum leaks and fuel pressure.

hope it helps.
joel