Repeatedly Running On A Low Tank?

I appreciate the context of how you gleaned this
information.

All I know (from google) is that a company called "Taishing
Electric Machine Company" apparently made a number of Honda
models' fuel pumps for a certain time period. I could not
even locate the material of which the pump rotor is made.
Probably a bit too proprietary/specialized for net
discussion and reports.

So of course other questions arise, like whether GM/Delphi
and Ford/Visteon used the same pump manufacturer as Toyota,
or Nissan, or Honda yada; does pumping debris from the
bottom of the tank clog things up requiring the pump to work
harder and so burdening the bearing surfaces of which you
speak; and so on.

Not saying you're wrong. Just saying I am not so sure the
article's simple claim that "perpetually running on fumes
can damage a car's fuel pump" is disproved by your
contentions, which I agree do shed light on some of the
issues here. Yours seems to be sound experience. I know you
know it is. Just opining with my humble stamp of approval,
worth less than the paper this is not written on.

snip for brevity

I appreciate the humility, though it may not be warranted.
My pump design experience is not specialized to fuel pumps
but to a number of marine applications.

I found these interesting:
http://www.carterfueldelivery.com/fuelpumps/pdf/support/TEC1620.pdf

http://www.tomorrowstechnician.com/Content/Site301/SmartProducts/CommonCausesofE_00000002018.pdf

Not to challenge your authority but more for the interested
readers here to ponder. The articles at the links above
certainly can be challenged in a number of ways. They may be
dated, for one.

 

it's kind of hard for hachiroku to understand that

1. an electric motor with very limited load doesn't get very hot -
certainly not hot enough to require liquid cooling.

it's harder yet for him to understand that

2. modern gasoline fuel injection pumps are typically "turbine" types,
and the impeller doesn't wear, much like the water pump in the radiator
circuit.

with old style pumps that used gear or scrolling vane pumping,
lubrication, and limited life, was indeed an issue. modern pumps such
as those used by honda last as long as the motor brushes, submerged or not.

 

most of the fear and irrational b.s. that creates fuel pump legend is
that of ancient scroll pump failures. most modern pumps don't have
them, so they don't fail through fuel-related causes, only the kinds of
quality issues that plague anything detroit. misattribution is the
stuff of usenet however...

 

I used to build fuel pumps for Pratt & Whitney. Surprisingly similar
design. They were obviously fuel cooled, too, but the difference was they
were bathed in fuel at all times, not just with fuel passing through.

As usual, rules of thumb don't wash with you. I keep the pump covered.

 

translation: you used to assemble. other people, people who knew what
they were doing, used to do the spec and design work.

"obviously"

like you change your oil at only 3k miles because it "obviously" needs it!

as usual, logic is an alien concept for you. tell me, have you been
having problems with elephant footprints in your butter again?

 

<YAWN>

 

so why do you bother? it's like watching a real-life, but very un-funny
homer simpson.

 

Sorry, Hachi...

I don't remember what I said before, but the danger in burning out the fuel
pump is if you let it run dry repeatedly. Toyota electric fuel pumps are
cooled and lubricated by the fuel flowing through it, not by the fuel around
it. Since it is mounted on top of the tank, where it would only be
submerged when the tank is fuel, it wouldn't make sense to have to rely on
it being submerged all the time when it would only be submerged when the
tank is full. Running with a low tank will not have any measurable effect
on fuel pump life.

Running with a low tank doesn't increase the odds that the fuel pump will
pick up more debris from the bottom of the tank than when the tank is full -
the odds are the same. If you think about cleaning a pool, the pool vacuum
picks up stuff off the bottom of the pool without having to empty the pool.
Even if there were debris at the bottom of the tank, the fuel pickup has a
screen that prevents any big stuff from being pulled into the fuel pump.

Running on a tank that is mostly empty could promote condensation in the
tank, which could eventually foul the injectors, but even that is a stretch.

The problem I see with running adding fuel a little at a time is the hassle
of constantly having to stop for fuel, and there is a greater chance of
running the tank completely dry, which if done often enough, is bad for the
fuel pump.

 

Ah, Faux News, or is it Fucks News? Our favourite TV tabloid.

 

When I worked in the industry, the North American car manufacturers
generally used different fuel pump manufacturers than the Japanese cars.
I doubt that that statement holds much validity anymore, and I can't
say with any certainty how purely true that was even then as I was only
involved in certain pumps for certain Ford and GM platforms.

Depends somewhat on the type of pumping section. Each type of pump has
advantages and disadvantages, such as pressure volume capabilities,
noise (which is a problem for roller vanes pumps if a vehicle is
supposed to be particularly quiet), tolerance to small and large
particle contamination, and tolerance to that bearing wear/shaft wobble
(again, having mostly due to pumping element clearance requirements or
lack thereof), of course cost to manufacture, and certainly many other
things I don't know about or simply haven't thought of. A turbine type
pump would be less subject to particle contamination than close or zero
clearance types such as gerotor or roller vane. For the record, my
experience was primarily with gerotor pumps.

I will repeat that with sealed tanks today, it is less of a problem.
There's always risk from picking up trash from the bottom of a service
stations tanks, but one of the by-products with the concern for not
releasing volatiles into the atmosphere is that their systems too are
now much more protected and closed/sealed - less subject to dirt, rust,
condensation/moisture.

I concede that there will be certainly be higher temperatures overall
with lower tank fuel levels. As Mr. White pointed out, with today's
cars not having recirc. systems, there is no heat picked up and returned
to the tank from the engine compartment. FWIW - the pump itself adds
about 75 watts worth of heat to everything. That's not much heat when
distributed over the mass of a few gallons of fuel and tank material,
with the exposed outer surface area of the tank also acting as a
radiator to the ambient air. But yes - certainly there will be *some*
temp. rise with less fuel in the tank. Let's say it's 5°F. Is that
enough to reduce the life of the pump to any significant degree? What
if it's 10°F? ...20°F?

It would be neat to see an article reporting the actual temp. increase
measured inside in the tank and inside the pump with full tank vs. half
full down to 2 or 3 gallons total in the tank from someone having
instrumented a "typical" vehicle. With all the warnings about it, you'd
think *someone* would have published such a study. Why is that not the
case? Makes me suspicious of the warnings that are repeated by people
who haven't a clue. Telltale signs of an urban legend maybe?

Interesting articles. Yes - the warnings about rust may be not be as
warranted today as they used to be. But how could you leave that out of
a bulletized list as a precaution to the service technician?

Thanks for the discussion!

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

About 75 watts. Not a lot, but not nothing either. It does indeed
require cooling (and lubrication) by the liquid going thru it. Without
that, indeed problems would quickly develop. Nice also to keep the two
missing ingredient for explosions - oxygen and fuel vapors - away from
the arcing of the brushes/commuator, eh?

Maybe typically, but there are other types in common use - roller vane
(at a noise disadvantage), and gerotor, which most of my experience is
with (some GM platforms). I don't know if the industry has migrated
mostly to one type since I left it 7 years ago, but I suspect there is
still some mix of types.

I guess what you're saying is that Honda uses mostly or totally turbine
pumps?

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Never owned a vehicle with an in-line pump?

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Any article on the subject on any news outlet says essentially the same
thing. It's all about parroting. If Fox News said that the stop sign
is red, it would not make the stop sign not be red. Get it?

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Oh man! Now you've got to keep that tank above 3/4 full all the time to
keep from destroying that pump!

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I live on the Gulf coast, and this time of year, we keep our tanks full,
never know when your going to have to pack up the wife, dogs, clothes, ect
and make a run for it, still have memories of Rita back in 05 arround here
in Texas.
Keep tank full, and eye to the sky.

 

The article is a reprint from the associated press. So carry your sarcasm
to the lefty loons. The only controversy in the whole article is the single
sentence that claims fuel pumps fail by running low on gas. Its not exactly
a wrong statement; its just an opinion from someone who believes it to be
true. This has been tossed around forever and nobody is going to change
their mind about what causes fuel pump failure. My fuel pump has lasted
over 200k miles so far. I thought it would last about 100k. When it quits,
I'll say it has served it life.

 

it can take advantage of it, but it doesn't /need/ it. windshield
motors are higher wattage and have no cooling other than ambient.

well, it's not coils, bearing or commutator/brush problems. and it's
only pump problems on gear or scroll types.

may well be, but this was posted to a honda forum and i'm responding to
that: honda use turbine type according to the service manuals i have.

apparently so.

the point is that the old fashioned generalizations of 30 years past are
ignorant irrational b.s. for fuel pumps, just like all the ignorant
irrational b.s. you get for oil change intervals. back in the 50's,
oils were inferior and a 3k mile oil change interval was a good idea.
today, with better combustion technology, better materials and better
oil formulation, you can easily, reliably, have a 10k mile oil change
for some cars, and yet we have ignorant irrational bullshitters falling
over themselves to waste their money and bleat at anyone who dares bring
a little updated fact into the room.

i understand that you cant force dumb people to be smart, but you can
sure encourage them to be silent!

 

i had to replace the fuel tank on my civic a while back after some
denting was fouling the float travel. on disposal of the old one, about
17 years vintage, i had the opportunity to drain and inspect. there was
a very little particulate matter in there, mostly metallic pump nozzle
scrapings, but you'd have had a hard time filling a thimble with it.
and no corrosion whatsoever. certainly nothing to cause any problem
with the filter sock.

no! say that can't be so!

and without it, there would be 90% less usenet traffic.

 

Ive seen it happen many times but only on Chevys. Of course it could be
coincidence but I don't think so. "I thought I ran out of gas because it was
really low but I put gas in it and it still wont start" <<<<like that.

p.s. you didn't design Chevy fuel pump components did you?

 

Are you saying that it is okay for a reporter to publish incorrect
information just as long as he believes it? Or are you saying that it
is okay for a reporter to publish his opinion as fact? What ever
happened to checking your facts before publishing?