Toyota Repair: 91 previa wont start, fuel pressure gauge, fuel pressure regulator

Question
I want to know if a Previa prime itself w/ gas at "on" (how long) position or it only supply gas when engine is running.  There is a spark when I tested it but still wont start.  I tried to open the line from the fuel filter but with no pressure  when i switch to  "on" position. It only has pressure when i tried to crank the engine.  Please advise.  Thanks


Answer
There is only fuel pressure when cranking the engine, there is no fuel pressure when just turning the key on so this is normal, the problem is somehere else.
There may be a problem with the fuel pressure regulator, the best way to go about this is to connect a fuel pressure gauge and make sure there is enough fuel pressure getting to the injectors.