Gas gauge fluctuating on 91 ls400

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:) :) - 28 Jan 2007 04:44 GMT

The gauge works great until about half tank then it goes to
empty...climbs to half...goes to 1/4 tank etc. Im thinking the only
thing it can be is the float in the tank? Does the whole fuelpump have
to be purchased? Any easy access to the fuel pump on the 91 ls400?
Thanks! :)

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Ray O - 28 Jan 2007 07:01 GMT

> The gauge works great until about half tank then it goes to
> empty...climbs to half...goes to 1/4 tank etc. Im thinking the only
> thing it can be is the float in the tank? Does the whole fuelpump have
> to be purchased? Any easy access to the fuel pump on the 91 ls400?
> Thanks! :)

The fuel gauge sender is separate from the fuel pump and fuel pressure
regulator. The fuel gauge sender is basically a float on an arm, and as the
arm moves up and down, the voltage from the fuel sender goes up and down,
and the fuel gauge is basically a volt meter.

If the gauge varies, it is possible that the float got detached from the end
of the arm and so it is sliding on the arm, the potentiometer in the fuel
sender is going bad, or there is loose or corroded wiring somewhere.

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Ray O
(correct punctuation to reply)

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