Elle wrote:

> "rigger" <dgrup@aol.com> wrote
> On Jun 2, 8:05 am, "Elle" <honda.lion...@spamnocox.net>
> wrote:
>
>>Barring presentation of a study showing no detrimental
>>effects of either regularly running on a very low tank or
>>running to empty, I think not doing these things is easy
>>enough and indeed an investment that costs one only a
>>litle
>>extra time getting gas over the life of the car. If
>>possibly
>>burdening the pump by forcing it to move air is not really
>>a
>>problem, then I remain concerned about dirt in the bottom
>>of
>>the tank clogging the filter and lines downstream of the
>>pump prematurely, or possibly wearing mechanical parts on
>>the pump, causing the pump to have to work harder, meaning
>>it draws more current, aging electrical parts more
>>quickly,
>>etc.
>
> snip
>
>
>>>How hot would the fuel need to
>>>become in order to accelerate the
>>
>>breakdown of the materials used in
>>
>>>the fuel pumps you're familiar with? In my mind I
>
> can't imagine most materials responding in a neg-
> ative manner unless temperatures reach very high
> levels (over 200 deg. F?) as I'd imagine they are
> chosen for temperature resistance, among other
> things.
>
>
> I agree. I would not expect an increased fuel temperature
> (due, say, to the pump recircing from a low fuel tank) will
> have a noticeable effect on pump part wear, one because I
> do not expect the temperature increase to be much (as Bill
> indicated) and two because I think the materials are durable
> enough, as you wrote.
>
> I am also concerned about how the fuel's sloshing,
> particularly when the vehicle is turning, could tend to
> starve the pump, making it work harder blah blah. Granted
> this would have to be at very low levels. The sloshing is
> certainly enough that I see my 91 Civic's fuel gage go lower
> on left turns; higher on right turns; when the gage reads
> below about 1/3 tank.
>
> Way too much argues against driving to or near an empty
> tank.
>
> I am speaking of electric fuel pumps, by the way, which are
> what are used on cars with fuel injection. So anyone having
> an older, carbureted car likely has a mechanical fuel pump
> and will have somewhat different concerns.
>
>

Just to be clear: the cars I mentioned all have/had electric fuel pumps.