RE: misc other problems (garbage in your gas...)

["Dan Sinclair" <sinclair@prospro.com>]

Good points boys.  Perhaps I've bought into a 'wives tale', but here's my
inspiration.  Fill a 5 gallon bucket with water, then put some sand and dirt
in the bottom and allow it to settle.  Now move the bucket around in
circles - jostle it - and observe.  Then pour off all but an inch of water
and do the same thing.  What you find is that in the first scenario the sand
and such will remain relatively still.  In the second scenario, you will
reproduce the "shallow water current" effect and you wind up with mud...
Granted, I hope the bottom of our gas tanks don't look like the bottom of a
creek, but I haven't actually laid eyes on the bottom of my tank so...
Agreed - filters and maintenance are the obvious answer.

FWIW, my personal spin on the subject was actually coming from years in the
motorcycle world, where the 'garbage' scenario resulted in clogged jets and
carb tinkering on several occasions.  This was usually attributable to the
motorcycle's 'reserve system' which essentially consists of a second fuel
line that draws fuel from below the level of the primary line.  Obviously
this wouldn't apply to cars.  I agree that garbage gets stirred up upon
re-fueling, but it settles very quickly, just like particulate matter in any
non-viscous liquid.  In motorcycles, this particulate matter would stay put
on the bottom and wouldn't get sucked into the primary fuel line, but if you
switched to reserve, you were essentially sucking the tank dry, and on more
occasions than I care to count, my carb took the brunt.  When your refueling
with pre-mix in a wind blow dirt filled desert, dirt is hard to avoid.  I
never had a debris problem while riding on the primary line.  Perhaps I've
over generalized in this case.

-----Original Message-----
From: Huw Powell [mailto:human@nh.ultranet.com]
Sent: Tuesday, March 23, 1999 3:32 PM
To: Dan Sinclair; quattro group
Subject: Re: 87 5kcsq Radio and misc other problems


> >>mine gets 24mpg.  Could be right.  Check by filling up the gas tank to
> FULL(about 19 gallons - 20)  And then dirve to bare min. and see what is
the
> mileage.<<
>
> Probably not a good idea...  On 8-10 year old cars, running the tank to
near
> Empty is a good way to suck water and garbage out of the bottom of your
tank
> and into your pump and/or fuel system.  Your trip computer's mileage
> accuracy will become the least of your worries...  :)

Huh?

1.  As far as I can see there isn't a floating fuel pickup in my tank,
so the stuff at the bottom is what gets used.

2.  The "garbage" is what the fuel filters are for.

3.  Water (in those quantites :-) is harmless.

4.  If there's that much crud in the gas tank it should be drained an
cleaned.

5.  Every time you add gas the tank gets stirred up, any crud is gonna
find the supply inlet no matter where it is.

6.  I frequently run down to the last tenth or two of a gallon (yikes!)
and haven't seen any problems ever.  Engine runs the same with full tank
or empty.

7.  A tank mounted, gasoline cooled, fuel pump is the only reason I can
see for not using the last couple of gallons of gas.

I could be full of it of course... ymmv

--
Huw Powell

http://www.thebook.com/human-speakers

82 Audi Coupe; 85 Coupe GT
http://www.nh.ultranet.com/~human