Agreed, though it is not very often necessary at times you need to let
air out so the dry pump can get a prime from the tank feed. The bleed
screw is a good place to do it. With enough fuel in the tank the level
gets above the high spot of the feeder tube inside the tank and then
gravity alone can more easily get fuel to the dry pump so it can pump
liquid like it was meant to. When the tank has been driven bone dry
there is trapped air that has to go somewhere before fuel can replace it
and the dry pump can't always make the 35 psi with just air to work
with. It is not an air pump. The pressure regulator blocks the air from
escaping to the return line until it sees that much pressure. So the
pump is working against compressed air and if the back pressure is too
high it sometimes can't do it unless gas has reached it since that is
what it is meant to pump, not air.

Mark

Max Wellhouse wrote:
> On 10/31/2013 1:17 PM, Scott Daniel wrote:
>> It's not neccessary to remove the screw from the fuel pressure testing
>> port to bleed the fuel lines.
>> It's a contiuously circulating fuel system .
>> Just cycle the key several times to pre-run the fuel pump and fill the
>> lines with gas.
>>
>>
>>
>
> Thanks Scott.  In the past(and I have lots of experience at this)
> bleeding the air out of the test port screw is the ONLY way my Vanagon
> will restart if I drive it dry.  If I catch it RIGHT t the first
> "hiccup", then I have a chance.
>
> DM&FS
>