Just another thought on this subject. A common event in EFI cars
that get driven to empty tanks is that the pump runs dry for some time and
this can degrade its performance or ruin it. It would then not prime
unless force-fed some fuel because of the internal wear in the
pump. An orifice would help a worn pump to prime in this situation.
This may be why there is such a variation of results we hear on this list
and elsewhere.
The bleeder orifice may be OK but I would worry about the condition of the
pump after an extended run-dry event. I always switch the pump off
immediately when this happens on my engine test stand.
This also jogs my memory about the variation of fuel pressure between the
primary & backup pumps during tests with a blocked return. I think it
was Ed that mentioned this.
Tracy
On
Wed, 15 Jun 2005 09:02:49 -0500 David Staten <Dastaten@earthlink.net>
writes:
>
>
> I would be a little concerned about the pump being higher than
the
> tank,
> given our recent discussions on vapor lock. Might
work fine, but who
> knows..
>
>
Dave
---------------------------------------
Hi Dave, I hear you,
but unless I'm sucking air in a leak between the
tanks do not "think" it is
a problem. You saw my comments about test
during the 40 hour flyoff and
have not experienced any difficulty yet.
Not sure how high on the firewall
that Ed's pumps are and know Tracy's
are on the floor.
Will be
careful running tanks dry when I fly cross country to make sure
I'm with in
gliding distance of an airstrip.
Bernie
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