Lack of gas

["John Hofstetter" <hofs@domain.elided>]

Michael and others,

Michael, I never doubted after the facts seemed to be in, that your
problem was fuel pump. Others, including me, have had somewhat similar
fuel pump problems. At one time I had a check valve just after my fuel
pump that wouldn't allow the gas back any farther than the valve. I
had a hell of a time finding that check valve, but it turned out there
was one made for diesel applications. 

There is also no doubt that some people, for example Bill in Tulare
who had the really new looking Terra, have a problem with the fuel
disappearing from the fuel bowl. In most cases I know of, this only
happens after sitting for a while, in some cases a matter of hours, in
others a matter of days. I'm sure that in the case of some carbs,
particularly Thermoquads, the gas is leaking out of the bowls and into
the manifold. In other cases, this doesn't seem possible, and I looked
at evaporation as a possible contributor to these empty bowls. It
can't all be evaporation, of course, because as you pointed out, the
evaporation from engine heat is a short term process, and again most
empty bowls appear after a matter of hours. I have nothing at stake in
the evaporation argument, as, if it is a factor at all, it isn't the
final answer. I have stood by my vehicles in the past, and listened to
the gas boil in the fuel bowls, so I know that the potential for fuel
loss must be there to some extent. 

I also certainly believe that gas drains out of the fuel line due to
diaphragm leaks or in Tom's (?) case, through a leaky fitting, but
logically if that happens and the fuel bowls are still full, the
engine should start and run for a while, in most cases, I would think,
allowing the pump to start refilling the bowls. 

Obviously, we are dealing with any of several factors in this
lack-of-gas problem, and in some cases may be dealing with more than
one of those factors combining to cause problems. 

Interestingly enough, one of the reasons that I have fuel injection is
to get away from these problems among others, but for the last couple
of months, an elusive electrical problem has made the running of the
electric fuel pump a sometimes-it-runs, and sometimes-it-doesn't
proposition. So far, I've not been diligent enough to track it down.
May be the bulkhead connectors, but it isn't affecting anything else,
except that sometimes when it is refusing to pump, the engine acts as
if it timed way too early, which it isn't. So, it seems to me that
whatever electrical problem is causing the fuel pump not to pump (in
which case I guess its a fuel no-pump), must also be causing the MSD
to change its timing.

Maybe I should spend more time looking at my vehicle and less time
scratching my head over other people's problems. Nah, old farts much
prefer to talk about things like mechanical problems and sex, than to
engage in them. Is there such a thing as mechanical ambition Viagra? 

John H.
----------
From: owner-ihc-digest@domain.elided (ihc-digest)
To: ihc-digest@domain.elided
Subject: ihc-digest V6 #831
Date: Wed, May 12, 1999, 11:05 PM


From: "J. Michael Shaw, II" <MikeIIDC@domain.elided>
Subject: Re: Fuel Pump draining Thermoquad

>David,
>For what its worth, in my opinion, there is no way that the fuel line
>could be sucking the gas back through the fuel pumps leaky diaphragm
>to the tank.

David and John, and everyone else who has discussed this-nowhere did I
say
anything even vaguely resembling the belief that the fuel lines could
be
"sucking the gas back," nor did I mean this.