The IP should draw enough to run, even down the highway. At least this was true for me with a non-functioning mechanical pump. I drove around for a month or two with a bad mechanical lift pump. The electric pump might be different.
The pump will only typically run for 3 secs after you turn the key on if you do not start the engine. You might be able to hear it as a slight whine. If you have the air bleed valve open, and cycle the key, you should see fuel come out if the system is primed and the pump is functional.
1984 M1009 CUCV Blazer. 6.2/TH400