Here is a question I have had for nearly 13 years and have been too
sheepish to ask. The fuel gauge in my 1980 Spit has never read higher
than about 2/3 full after a fill-up. When the gauge reads empty and
I do fill up, it takes only 6.5 or 7 gallons. I always assumed the
gauge reads wrong and that there must be a few gallons remaining
even when it reads empty. But, working on that theory, I have
occasionally run out of gas and found that the fill-up still
required only 7 gallons. This past summer I replaced the sending
unit with another taken off a parts car, and it read the same as
my original one. The guage does read full when the lead wires to
the sender are shorted though. Then I found a way to adjust the
sender so the gauge reads full when the tank is full, but now it
reads about 1/3 full when I run out of gas. So it appears that my
tank capacity is about 7 gallons. But the tank looks just like the
original ones pictured in the parts catalogs. So, if it is original,
I see only two possibilities:
1) There is something taking up space in the tank. But, if that is
the case, it would have to be blocking the float in some way too.
2) Maybe when I think I have run out of fuel, I really haven't. Last
week, when I ran out on the way to work, there was an obvious
vacuum hiss when I popped the filler cap. I was in too much of
a hurry to try to restart; I just dumped about a half gallon in
from a small can I have started carrying recently. I know, I know,
that is not smart, and I will stop as soon as I either solve this
problem or reset the sender so the gauge reads empty when it really
is empty. Anyway, if there is a problem with the breather line
and the carbon cannister that is producing a vacuum which overcomes
the fuel pump, why is my gauge not reading full scale? In all
honesty, I have come to believe that when I run out of gas, I'm
REALLY out; I don't hear any sloshing when I rock the car.
So, WHAT'S UP? Thanks for any insight you can provide.
Tim
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Tim Gaines
Clinton, SC
1980 Spitfire
1974 TR6
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