Re: Repeatedly Running On A Low Tank?
 

"Bill Putney" <bptn@kinez.net> wrote
> Elle wrote:
>> What are the leading causes of fuel pump failure? If it's
>> "age," what exactly causes aging to accelerate?
>
> Wear of the bearings (which for most pumps are actually
> plastic holes in pump/motor end caps (basically, plastic
> bushings) and wear of the brushes.
>
> Usually the plastic end caps (that act as the bearings for
> the armature shaft) are glass filled. The molded bearing
> (bushing) surfaces have a microscopically thin film of
> plastic separating the glass fibers from the metal shaft -
> an inherent result of the molding process of glass-filled
> plastics. Once that thin film wears thru, the very
> abrasive glass wears the metal shaft faster than the
> plastic itself wears believe it or not (I learned this
> when I worked as a designer/engineer/manager for a
> supplier of fuel pump parts to GM/Delphi and Ford/Visteon.

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. :-)

> Once there is significant play between the shaft and the
> bearings/bushings, the armature literally rattles around
> and eventually crashes into the
snip for brevity

> Perhaps I shed some light for you with some of my
> comments. Certainly I do not have anywhere near
> exhaustive knowledge of the subject.

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/fu...rt/TEC1620.pdf

http://www.tomorrowstechnician.com/C...0000002018.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.

Re: Repeatedly Running On A Low Tank?
 

Bill Putney wrote:
> hachiroku wrote:
>> On Mon, 02 Jun 2008 05:53:18 -0700, jim beam wrote:
>>
>>>> It's like every "factual" story in the media is just all spin. So,
>>>> is this guy an Oil Company shill trying to get us to fill-up and
>>>> inflate the price of gasoline?
>>> no, that could /never/ happen. not ever. not in a million bajillion
>>> years. no sir.
>>>
>>> oh, wait, the fuel pump thing is utter bullshit, so...
>>
>>
>> Once again you show how little you know.
>>
>> The fuel pump is cooled by fuel. If you run on a low tank that doesn't
>> cover the fuel pump, it can fail prematurely. At $190~425 for a fuel
>> pump.
>> it's probably cheaper to keep enough fuel in the tank to cool the pump.
>
> The overwhelming majority of the cooling (and *all* of the lubrication)
> of the pump and its internal components comes from the constant flow of
> fuel thru the pump and around each component. Very little cooling comes
> from the mostly stangant fuel surrounding the pump.


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.

Re: Repeatedly Running On A Low Tank?
 

Elle wrote:
> "Bill Putney" <bptn@kinez.net> wrote
>> Elle wrote:
>>> What are the leading causes of fuel pump failure? If it's
>>> "age," what exactly causes aging to accelerate?
>> Wear of the bearings (which for most pumps are actually
>> plastic holes in pump/motor end caps (basically, plastic
>> bushings) and wear of the brushes.
>>
>> Usually the plastic end caps (that act as the bearings for
>> the armature shaft) are glass filled. The molded bearing
>> (bushing) surfaces have a microscopically thin film of
>> plastic separating the glass fibers from the metal shaft -
>> an inherent result of the molding process of glass-filled
>> plastics. Once that thin film wears thru, the very
>> abrasive glass wears the metal shaft faster than the
>> plastic itself wears believe it or not (I learned this
>> when I worked as a designer/engineer/manager for a
>> supplier of fuel pump parts to GM/Delphi and Ford/Visteon.
>
> 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. :-)
>
>> Once there is significant play between the shaft and the
>> bearings/bushings, the armature literally rattles around
>> and eventually crashes into the
> snip for brevity
>
>> Perhaps I shed some light for you with some of my
>> comments. Certainly I do not have anywhere near
>> exhaustive knowledge of the subject.
>
> 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/fu...rt/TEC1620.pdf
>
> http://www.tomorrowstechnician.com/C...0000002018.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.
>
>


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...

Re: Repeatedly Running On A Low Tank?
 

On Mon, 02 Jun 2008 19:03:32 -0700, jim beam wrote:

>> The overwhelming majority of the cooling (and *all* of the lubrication)
>> of the pump and its internal components comes from the constant flow of
>> fuel thru the pump and around each component. Very little cooling comes
>> from the mostly stangant fuel surrounding the pump.
>
>
> 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.


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.

Re: Repeatedly Running On A Low Tank?
 

Hachiroku ãƒ�ãƒ�ãƒã‚¯ wrote:
> On Mon, 02 Jun 2008 19:03:32 -0700, jim beam wrote:
>
>>> The overwhelming majority of the cooling (and *all* of the lubrication)
>>> of the pump and its internal components comes from the constant flow of
>>> fuel thru the pump and around each component. Very little cooling comes
>>> from the mostly stangant fuel surrounding the pump.
>>
>> 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.
>
>
> I used to build fuel pumps for Pratt & Whitney.

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



> Surprisingly similar
> design. They were obviously

"obviously"

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


> 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.

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

Re: Repeatedly Running On A Low Tank?
 

On Mon, 02 Jun 2008 20:44:08 -0700, jim beam wrote:

>> I used to build fuel pumps for Pratt & Whitney.
>
> translation: you used to assemble. other people, people who knew what
> they were doing, used to do the spec and design work.
>
>
>
>> Surprisingly similar
>> design. They were obviously
>
> "obviously"
>
> like you change your oil at only 3k miles because it "obviously" needs it!
>
>
>> 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.
>
> as usual, logic is an alien concept for you. tell me, have you been
> having problems with elephant footprints in your butter again?


<YAWN>

Re: Repeatedly Running On A Low Tank?
 

Hachiroku ãƒ�ãƒ�ãƒã‚¯ wrote:
> On Mon, 02 Jun 2008 20:44:08 -0700, jim beam wrote:
>
>>> I used to build fuel pumps for Pratt & Whitney.
>> translation: you used to assemble. other people, people who knew what
>> they were doing, used to do the spec and design work.
>>
>>
>>
>>> Surprisingly similar
>>> design. They were obviously
>> "obviously"
>>
>> like you change your oil at only 3k miles because it "obviously" needs it!
>>
>>
>>> 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.
>> 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.

Re: Repeatedly Running On A Low Tank?
 

"Hachiroku ????" <Trueno@ae86.GTS> wrote in message
news:G811k.2158$Kw3.1287@trndny01...
> On Mon, 02 Jun 2008 18:20:56 +0000, Daniel Who Wants to Know wrote:
>
>>> The fuel pump is cooled by fuel. If you run on a low tank that doesn't
>>> cover the fuel pump, it can fail prematurely. At $190~425 for a fuel
>>> pump. it's probably cheaper to keep enough fuel in the tank to cool the
>>> pump.
>>>
>>> What did I expect from someone who changes his oil at 12,000 miles
>>> whether it needs it or not.
>>>
>>> Reply when you get a clue...
>>>
>>>
>>>
>> Sorry to burst your bubble hachi but the level of fuel outside the pump
>> means nothing. As has been mentioned before the fuel being pumped goes
>> directly through the motor assembly on its way from one end of the pump
>> to the other.
>
> But...But...Ray told me I was in danger of burning out my fuel pump in my
> Supra when I got it because the tank had so many holes I had to keep it
> below 1/4 tank.
>
> I trust what Ray says...
>

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.
--

Ray O
(correct punctuation to reply)

Re: Repeatedly Running On A Low Tank?
 

Don't Taze Me, Bro! wrote:
> Consider filling up your tank and not letting it drop below halfway, instead
> of keeping it on low and only putting in 2 gallons here and there...
>
> http://www.foxnews.com/story/0,2933,361347,00.html

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

Re: Repeatedly Running On A Low Tank?
 

Elle wrote:
> "Bill Putney" <bptn@kinez.net> wrote
>> Elle wrote:
>>> What are the leading causes of fuel pump failure? If it's
>>> "age," what exactly causes aging to accelerate?
>> Wear of the bearings (which for most pumps are actually
>> plastic holes in pump/motor end caps (basically, plastic
>> bushings) and wear of the brushes.
>>
>> Usually the plastic end caps (that act as the bearings for
>> the armature shaft) are glass filled. The molded bearing
>> (bushing) surfaces have a microscopically thin film of
>> plastic separating the glass fibers from the metal shaft -
>> an inherent result of the molding process of glass-filled
>> plastics. Once that thin film wears thru, the very
>> abrasive glass wears the metal shaft faster than the
>> plastic itself wears believe it or not (I learned this
>> when I worked as a designer/engineer/manager for a
>> supplier of fuel pump parts to GM/Delphi and Ford/Visteon.
>
> 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.

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.

> 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.

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.

> 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. :-)

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?

>> Once there is significant play between the shaft and the
>> bearings/bushings, the armature literally rattles around
>> and eventually crashes into the
> snip for brevity
>
>> Perhaps I shed some light for you with some of my
>> comments. Certainly I do not have anywhere near
>> exhaustive knowledge of the subject.
>
> 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/fu...rt/TEC1620.pdf
>
> http://www.tomorrowstechnician.com/C...0000002018.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.

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')

Re: Repeatedly Running On A Low Tank?
 

jim beam wrote:
> Bill Putney wrote:
>> hachiroku wrote:
>>> On Mon, 02 Jun 2008 05:53:18 -0700, jim beam wrote:
>>>
>>>>> It's like every "factual" story in the media is just all spin. So,
>>>>> is this guy an Oil Company shill trying to get us to fill-up and
>>>>> inflate the price of gasoline?
>>>> no, that could /never/ happen. not ever. not in a million
>>>> bajillion years. no sir.
>>>>
>>>> oh, wait, the fuel pump thing is utter bullshit, so...
>>>
>>>
>>> Once again you show how little you know.
>>>
>>> The fuel pump is cooled by fuel. If you run on a low tank that doesn't
>>> cover the fuel pump, it can fail prematurely. At $190~425 for a fuel
>>> pump.
>>> it's probably cheaper to keep enough fuel in the tank to cool the pump.
>>
>> The overwhelming majority of the cooling (and *all* of the
>> lubrication) of the pump and its internal components comes from the
>> constant flow of fuel thru the pump and around each component. Very
>> little cooling comes from the mostly stangant fuel surrounding the pump.
>
>
> 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.

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?

> 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.

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.

> 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.

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')

Re: Repeatedly Running On A Low Tank?
 

Hachiroku ãƒ�ãƒ�ãƒã‚¯ wrote:
> On Mon, 02 Jun 2008 19:03:32 -0700, jim beam wrote:

>> 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.

> 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.

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')

Re: Repeatedly Running On A Low Tank?
 

Gib Bogle wrote:
> Don't Taze Me, Bro! wrote:
>> Consider filling up your tank and not letting it drop below halfway,
>> instead of keeping it on low and only putting in 2 gallons here and
>> there...
>>
>> http://www.foxnews.com/story/0,2933,361347,00.html
>
> Ah, Faux News, or is it s News? Our favourite TV tabloid.

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')

Re: Repeatedly Running On A Low Tank?
 

Ray O wrote:
> "Hachiroku ????" <Trueno@ae86.GTS> wrote in message
> news:G811k.2158$Kw3.1287@trndny01...

>> But...But...Ray told me I was in danger of burning out my fuel pump in my
>> Supra when I got it because the tank had so many holes I had to keep it
>> below 1/4 tank.
>>
>> I trust what Ray says...

> ...Since it is mounted on top of the tank, where it would only be
> submerged when the tank is fuel,

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')

Re: Repeatedly Running On A Low Tank?
 

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.
"Don't Taze Me, Bro!" <N00One187@NoWhere.Com> wrote in message
news:%HP0k.6360$%Z1.4068@trnddc05...
> Consider filling up your tank and not letting it drop below halfway,
> instead of keeping it on low and only putting in 2 gallons here and
> there...
>
> http://www.foxnews.com/story/0,2933,361347,00.html
>
> Not because you could run out of gas and get stranded but because
> repeatedly running on low tends to ruin the fuel pump.
>

Re: Repeatedly Running On A Low Tank?
 

Gib Bogle wrote:
> Don't Taze Me, Bro! wrote:
>> Consider filling up your tank and not letting it drop below halfway,
>> instead of keeping it on low and only putting in 2 gallons here and
>> there... http://www.foxnews.com/story/0,2933,361347,00.html
>
> Ah, Faux News, or is it s News? Our favourite TV tabloid.

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.

Re: Repeatedly Running On A Low Tank?
 

Bill Putney wrote:
> jim beam wrote:
>> Bill Putney wrote:
>>> hachiroku wrote:
>>>> On Mon, 02 Jun 2008 05:53:18 -0700, jim beam wrote:
>>>>
>>>>>> It's like every "factual" story in the media is just all spin. So,
>>>>>> is this guy an Oil Company shill trying to get us to fill-up and
>>>>>> inflate the price of gasoline?
>>>>> no, that could /never/ happen. not ever. not in a million
>>>>> bajillion years. no sir.
>>>>>
>>>>> oh, wait, the fuel pump thing is utter bullshit, so...
>>>>
>>>>
>>>> Once again you show how little you know.
>>>>
>>>> The fuel pump is cooled by fuel. If you run on a low tank that doesn't
>>>> cover the fuel pump, it can fail prematurely. At $190~425 for a fuel
>>>> pump.
>>>> it's probably cheaper to keep enough fuel in the tank to cool the pump.
>>>
>>> The overwhelming majority of the cooling (and *all* of the
>>> lubrication) of the pump and its internal components comes from the
>>> constant flow of fuel thru the pump and around each component. Very
>>> little cooling comes from the mostly stangant fuel surrounding the pump.
>>
>>
>> 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.
>
> About 75 watts. Not a lot, but not nothing either. It does indeed
> require cooling (and lubrication) by the liquid going thru it.

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


> Without
> that, indeed problems would quickly develop.

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


> Nice also to keep the two
> missing ingredient for explosions - oxygen and fuel vapors - away from
> the arcing of the brushes/commuator, eh?
>
>> 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.
>
> 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.

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.


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

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!

Re: Repeatedly Running On A Low Tank?
 

Bill Putney wrote:
> Elle wrote:
>> "Bill Putney" <bptn@kinez.net> wrote
>>> Elle wrote:
>>>> What are the leading causes of fuel pump failure? If it's "age,"
>>>> what exactly causes aging to accelerate?
>>> Wear of the bearings (which for most pumps are actually plastic holes
>>> in pump/motor end caps (basically, plastic bushings) and wear of the
>>> brushes.
>>>
>>> Usually the plastic end caps (that act as the bearings for the
>>> armature shaft) are glass filled. The molded bearing (bushing)
>>> surfaces have a microscopically thin film of plastic separating the
>>> glass fibers from the metal shaft - an inherent result of the molding
>>> process of glass-filled plastics. Once that thin film wears thru,
>>> the very abrasive glass wears the metal shaft faster than the plastic
>>> itself wears believe it or not (I learned this when I worked as a
>>> designer/engineer/manager for a supplier of fuel pump parts to
>>> GM/Delphi and Ford/Visteon.
>>
>> 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.
>
> 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.
>
>> 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.
>
> 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 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.



>
>> 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. :-)
>
> 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.

no! say that can't be so!


> Telltale signs of an urban legend maybe?

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


>
>>> Once there is significant play between the shaft and the
>>> bearings/bushings, the armature literally rattles around and
>>> eventually crashes into the
>> snip for brevity
>>
>>> Perhaps I shed some light for you with some of my comments.
>>> Certainly I do not have anywhere near exhaustive knowledge of the
>>> subject.
>>
>> 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/fu...rt/TEC1620.pdf
>>
>> http://www.tomorrowstechnician.com/C...0000002018.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.
>
> 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')

Re: Repeatedly Running On A Low Tank?
 

"Bill Putney" <bptn@kinez.net> wrote in message
news:6ai0kvF37k2jlU1@mid.individual.net...
> Don't Taze Me, Bro! wrote:
>> Consider filling up your tank and not letting it drop below halfway,
>> instead of keeping it on low and only putting in 2 gallons here and
>> there...
>>
>> http://www.foxnews.com/story/0,2933,361347,00.html
>>
>> Not because you could run out of gas and get stranded but because
>> repeatedly running on low tends to ruin the fuel pump.
>
> I see that thing about running low on fuel damaging fuel pumps posted all
> over the internet, but personally I think that's total b.s.
>
> All the critical parts in the fuel pump - bearings (bushings), armature,
> brushes/commutator, pumping elements (vanes, rotors, or rollers) - are
> constantly bathed in the fuel as it flows thru the pump. That lubricates
> and cools the parts regardless of fuel level in the tank.
>
> With regulator bypass pumping/circulation that modern cars have, there is
> full volume of fuel going thru the pump at all times it is running
> regardless of engine demand. The only effect of low fuel in the tank is a
> slight temperature rise of the volume of fuel in the tank (due to same
> electrical power dissipated in the pump being absorbed by less mass of
> fuel), and that rise will be very small - power used by fuel pump is
> small - temperature rise of the fuel in the tank and the tank itself will
> be very small - lots of mass compared to the power being dissipated.
>
> *BUT* - again - the fuel is constantly flowing thru and around all
> internal components of the pump whenever it is running providing cooling
> (unless you actually run out and the engine stops - but that is a
> different scenario altogether, and even then, the pump will still be full
> of fuel at that point with a full column of fuel from its lowest end to
> the fuel rail - only the pickup will be filled with air, and there won't
> be any flow - and most cars turn the pump off when the computer senses
> that the engine is no longer running).
>
> If anyone wants to argue this, be sure of your facts beforehand - I used
> to design automotive fuel pump components.
>
> Bill Putney
> (To reply by e-mail, replace the last letter of the alphabet in my address
> with the letter 'x')

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? ;)

Re: Repeatedly Running On A Low Tank?
 

On Tue, 3 Jun 2008 07:06:23 -0500, "George" <nospam@invalid.net>
wrote:
>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.

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?

Re: Repeatedly Running On A Low Tank?
 

On 6/3/08 10:51 AM, in article kspa449vsa7f1g1rusjb9d523p4ta9r3n7@4ax.com,
"Retired VIP" <jackj.extradots.180@windstream.net> wrote:

> On Tue, 3 Jun 2008 07:06:23 -0500, "George" <nospam@invalid.net>
> wrote:
>> 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.
>
> 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?

It went out the same day they started soliciting advertising for the evening
news and turned it into a for-profit operation. Just don't do it with
politics & get caught (remember Dan Rather?).

Re: Repeatedly Running On A Low Tank?
 

On Jun 2, 4:51 pm, Bill Putney <b...@kinez.net> wrote:
> ToMh wrote:
> > On Jun 2, 2:12 am, "Don't Taze Me, Bro!" <N00One...@NoWhere.Com>
> > wrote:
> >> Consider filling up your tank and not letting it drop below halfway, instead
> >> of keeping it on low and only putting in 2 gallons here and there...
>
> >>http://www.foxnews.com/story/0,2933,361347,00.html
>
> >> Not because you could run out of gas and get stranded but because repeatedly
> >> running on low tends to ruin the fuel pump.
>
> > The fuel pump is like any other fluid pump. it requires the liquid
> > running through it to lubricate and cool it. If you run a pump dry,
> > its seals can burn out fast.
>
> No. There are no dynamic seals in fuel pumps like in a typical
> automotive water pump. Running dry (not a credible situation in
> general) would not affect case seals (which are static crimped seals).



>
> > But as long as there is fluid running
> > through it, it will be fine. So as long as there is gas running
> > through the pump, it won't get damaged, but I could certainly see how
> > it could be damaged if you let it run out of gas...
>
> Not likely since the pumping section is at the bottom of the pump, so
> when you "run out of gas", there is a column of fuel extending from the
> pumping section of the pump (at its very bottom), thru the pump, all the
> way to the fuel rail and injectors. Granted that column of fuel is not
> moving, but it's there nonetheless. And the engine dies, and the
> computer turns the pump off in a matter of seconds. No real chance for
> significant damage from heat or lack of lubrication.
>
> > Just having a low
> > tank, without the pump running dry, can't possibly cause any
> > problems.
>
> I'll buy that.
>
>
Thanks for the info. It sounds like you'd have to practically let all
the gas evaporate before it causes a problem.

Re: Repeatedly Running On A Low Tank?
 

On Tue, 3 Jun 2008 00:04:59 -0500, "Ray O"
<rokigawaATtristarassociatesDOTcom> wrote:


>
>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.


Moderately low is OK. Severely low is a NO-NO.
The pump must NOT be allowed to draw air. This happens when the fuel
gets down to about 3" deep on wasboard road surfaces, where the bottom
of the tank shakes and makes the fuel spash and spray around inside
the tank.
The motors get insufficient cooling and the pump runs dry - scoring
and damaging the pump cell.
>
>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.

And IF there is water (and supended rust) in the bottom of the tank it
WILL get picked up when the tank is low. It will NEVER get picked up
when the tank is full. And SURPRISE!! - It costs the same amount to
keep the TOP 1/8 tank full as it does the bottom 1/8.
>
>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.

** Posted from http://www.teranews.com **

Re: Repeatedly Running On A Low Tank?
 

On Tue, 03 Jun 2008 15:51:26 GMT, Retired VIP
<jackj.extradots.180@windstream.net> wrote:

>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?

I have never, ever read a news story or seen one on TV where I was
intimately familiar with the facts of the story that I didn't see
glaring errors in either the facts or simply the selection of facts
they chose to present (distorting the true story). Reporter
incompetence is the issue at least half the time (not even checking
facts).

My observations have led me to believe that every news and newspaper
story is most likely similarly inaccurate.

Re: Repeatedly Running On A Low Tank?
 

On Tue, 03 Jun 2008 00:04:59 -0500, Ray O wrote:

>> But...But...Ray told me I was in danger of burning out my fuel pump in
>> my Supra when I got it because the tank had so many holes I had to keep
>> it below 1/4 tank.
>>
>> I trust what Ray says...
>>
>>
> 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.

On the Supra it is quite well into the tank, probably an inch or two from
the bottom. This discussion came up a couple years ago when I still had
my 'holey' tank and could only run 1/4 tank at a time, and you
recommended fixing it posthaste as this condition could be detrimental to
the pump.

Since I take what you say as Gospel ( ;) ), I repaired the tank ASAP
(Also in an effort to keep at that time $1.78/gallon gas from just
evaporating into thin air...).

Better safe than sorry, esp @ $199 for an OEM Denso pump!

Re: Repeatedly Running On A Low Tank?
 

On Tue, 03 Jun 2008 06:49:22 -0400, Bill Putney wrote:

>> ...Since it is mounted on top of the tank, where it would only be
>> submerged when the tank is fuel,
>
> Oh man! Now you've got to keep that tank above 3/4 full all the time to
> keep from destroying that pump!

It's mounted low on the bracket, so 1/3 will probably cover it.

But, I keep the tank full as much as possible. I don't want my *new* $375
fuel tank rotting out!

Re: Repeatedly Running On A Low Tank?
 

On Mon, 02 Jun 2008 21:40:31 -0700, jim beam wrote:

>>>> 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.
>>> 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.

When it comes between listening to you, or a former Toyota Factory
Service rep, guess who wins?
(HINT: it's not you!)

You already proved how much you know with your 12,000 mile whether-it-
needs-it-or-not oil changes...

Re: Repeatedly Running On A Low Tank?
 

On Tue, 03 Jun 2008 06:24:05 -0400, Bill Putney wrote:

> Hachiroku ãƒ�ãƒ�ãƒã‚¯ wrote:
>> On Mon, 02 Jun 2008 19:03:32 -0700, jim beam wrote:
>
>>> 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.
>
>> 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.
>
> 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')

A long, long time ago, but they are a different design.

Re: Repeatedly Running On A Low Tank?
 

On Tue, 03 Jun 2008 06:01:54 -0700, jim beam wrote:

>> About 75 watts. Not a lot, but not nothing either. It does indeed
>> require cooling (and lubrication) by the liquid going thru it.
>
> it can take advantage of it, but it doesn't /need/ it. windshield
> motors are higher wattage and have no cooling other than ambient.

I would absolutely believe that you drive around with the washer button
depressed constantly.

Whew, You're a piece of work...

Re: Repeatedly Running On A Low Tank?
 

On Tue, 03 Jun 2008 06:01:54 -0700, jim beam wrote:

>> 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.
>
> 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.

I didn't know Mad Magazine published Service Manuals...

Re: Repeatedly Running On A Low Tank?
 

On Tue, 03 Jun 2008 06:01:54 -0700, jim beam wrote:

> 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!

So why don't you STFU, then?

Re: Repeatedly Running On A Low Tank?
 

George wrote:
> Gib Bogle wrote:
>> Don't Taze Me, Bro! wrote:
>>> Consider filling up your tank and not letting it drop below halfway,
>>> instead of keeping it on low and only putting in 2 gallons here and
>>> there... http://www.foxnews.com/story/0,2933,361347,00.html
>> Ah, Faux News, or is it s News? Our favourite TV tabloid.
>
> The article is a reprint from the associated press. So carry your sarcasm
> to the lefty loons.

You don't have to be a lefty loon to despise the low standards of Fox.
You do have to be a righty loon to fail to see them.

Re: Repeatedly Running On A Low Tank?
 

"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message
news:G_adnYO148I_SNnVnZ2dnUVZ_vninZ2d@comcast.com. ..

> 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.

While it might be mounted throught the top of the tank, I believe in most
cases the pump is actully near the bottom of the tank. I looked at my shop
manual for the Camry and it appears that the fuel pump stack is set up so
that the pump is mounted directly on top of the pick-up sock. This implies
it is almost always surrounded by some fuel unless level in the tank is very
low. Here is a picture of a Camry Fuel Pump assembly -
http://info.rockauto.com/getimage/ge...imageurl=http%

Ed

Re: Repeatedly Running On A Low Tank?
 

"hachiroku" <Trueno@ae86.GTS> wrote in message
news:Zwg1k.2161$BV.1695@trndny05...
> On Tue, 03 Jun 2008 06:49:22 -0400, Bill Putney wrote:
>
>>> ...Since it is mounted on top of the tank, where it would only be
>>> submerged when the tank is fuel,
>>
>> Oh man! Now you've got to keep that tank above 3/4 full all the time to
>> keep from destroying that pump!
>
> It's mounted low on the bracket, so 1/3 will probably cover it.
>
> But, I keep the tank full as much as possible. I don't want my *new* $375
> fuel tank rotting out!

The tank is actually steel? I thought everyone changed to plastic tanks
years ago.

Ed

Re: Repeatedly Running On A Low Tank?
 

jim beam wrote:
> Bill Putney wrote:
>> jim beam wrote:

>>> 1. an electric motor with very limited load doesn't get very hot -
>>> certainly not hot enough to require liquid cooling.
>>
>> About 75 watts. Not a lot, but not nothing either. It does indeed
>> require cooling (and lubrication) by the liquid going thru it.
>
> it can take advantage of it, but it doesn't /need/ it. windshield
> motors are higher wattage and have no cooling other than ambient.
>
>
>> Without that, indeed problems would quickly develop.
>
> well, it's not coils, bearing or commutator/brush problems. and it's
> only pump problems on gear or scroll types.

You are talking to the guy who designed and power limit-tested the
EMI/RFI coils on a certain GM gerotor pump. Believe me: The wire was
sized minimally for reliable life in fuel (for cooling) - 24 ga. solid
copper magnet wire carrying approx. 5 amps. I also designed the plastic
brush holder which also served as the motor/pump end cap. The "bearing"
(bushing) on that end is merely a hole precision-molded into the
plastic. The fuel is needed for lubrication for the bearings and shaft
to last a reasonable period without the armature rattling around and
crashing into the magnets. With fuel, bearing/shaft life is reasonable.
Without fuel, it would not be. You would not get away with a metal
shaft/plastic bushing bearing design on a windshield wiper motor -
because of the lubrication, you can on a fuel pump.

The powders that go into the molded brushes are specifically designed
for use in gasoline. You would *not* use the same materials in the
brushes for use in gasoline as for use in air. High current-density
brushes (like in starter motors) have a *lot* of copper in them. Fuel
pump brushes are almost pure carbon/graphite.

>> Nice also to keep the two missing ingredient for explosions - oxygen
>> and fuel vapors - away from the arcing of the brushes/commuator, eh?
>>
>>> 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.
>>
>> 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.
>
> 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.

>>> 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.

The motor itself (bearings, brushes, armature) would not last long
without the fuel. The turbine fan of course has no solid-to-solid
rubbing/wear so I'll give you that.

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

In general you may be right. However, there are some specific motors in
very recent years that are extremely sensitive (in a negative way) to
oil changes much beyond 3000 miles. Examples: Chrysler 2.7L, certain
Toyota engines, and I believe certain Honda engines. Try running those
on 10k miles change intervals, and they will totally sludge up and fail
before 100k miles (typically 60-80k miles). I know almost nothing of
the Toyota and Honda problems beyond what I read, but I am more familiar
with the Chrysler 2.7L and its sludge/failure problems.

As for running pump with fuel low in the tank, I was glad to see Ray O.
point out that many pumps are actually positioned very high in the tank
so that it is impractical to keep the fuel high enough to guarantee that
they're submerged all the time. I suspected as much, but wasn't sure,
so I kept quiet on that point - until today.

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

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

Re: Repeatedly Running On A Low Tank?
 

jim beam wrote:
> Bill Putney wrote:

>> 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.
>
> no! say that can't be so!

:)

>> Telltale signs of an urban legend maybe?
>
> and without it, there would be 90% less usenet traffic.

Well - that, global warming, and K&N air filters. :)

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

Re: Repeatedly Running On A Low Tank?
 

ScottM wrote:
> "Bill Putney" <bptn@kinez.net> wrote in message
> news:6ai0kvF37k2jlU1@mid.individual.net...
>> Don't Taze Me, Bro! wrote:
>>> Consider filling up your tank and not letting it drop below halfway,
>>> instead of keeping it on low and only putting in 2 gallons here and
>>> there...
>>>
>>> http://www.foxnews.com/story/0,2933,361347,00.html
>>>
>>> Not because you could run out of gas and get stranded but because
>>> repeatedly running on low tends to ruin the fuel pump.
>> I see that thing about running low on fuel damaging fuel pumps posted all
>> over the internet, but personally I think that's total b.s.
>>
>> All the critical parts in the fuel pump - bearings (bushings), armature,
>> brushes/commutator, pumping elements (vanes, rotors, or rollers) - are
>> constantly bathed in the fuel as it flows thru the pump. That lubricates
>> and cools the parts regardless of fuel level in the tank.
>>
>> With regulator bypass pumping/circulation that modern cars have, there is
>> full volume of fuel going thru the pump at all times it is running
>> regardless of engine demand. The only effect of low fuel in the tank is a
>> slight temperature rise of the volume of fuel in the tank (due to same
>> electrical power dissipated in the pump being absorbed by less mass of
>> fuel), and that rise will be very small - power used by fuel pump is
>> small - temperature rise of the fuel in the tank and the tank itself will
>> be very small - lots of mass compared to the power being dissipated.
>>
>> *BUT* - again - the fuel is constantly flowing thru and around all
>> internal components of the pump whenever it is running providing cooling
>> (unless you actually run out and the engine stops - but that is a
>> different scenario altogether, and even then, the pump will still be full
>> of fuel at that point with a full column of fuel from its lowest end to
>> the fuel rail - only the pickup will be filled with air, and there won't
>> be any flow - and most cars turn the pump off when the computer senses
>> that the engine is no longer running).
>>
>> If anyone wants to argue this, be sure of your facts beforehand - I used
>> to design automotive fuel pump components.
>>
>> Bill Putney
>> (To reply by e-mail, replace the last letter of the alphabet in my address
>> with the letter 'x')
>
> 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? ;)

Actually - yes. But we'd have to know which pump/platform.

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

Re: Repeatedly Running On A Low Tank?
 

Retired VIP wrote:

> 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?

Pfft! That's old school.

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

Re: Repeatedly Running On A Low Tank?
 

Bill Putney wrote:
> jim beam wrote:
>> Bill Putney wrote:
>>> jim beam wrote:
>
>>>> 1. an electric motor with very limited load doesn't get very hot -
>>>> certainly not hot enough to require liquid cooling.
>>>
>>> About 75 watts. Not a lot, but not nothing either. It does indeed
>>> require cooling (and lubrication) by the liquid going thru it.
>>
>> it can take advantage of it, but it doesn't /need/ it. windshield
>> motors are higher wattage and have no cooling other than ambient.
>>
>>
>>> Without that, indeed problems would quickly develop.
>>
>> well, it's not coils, bearing or commutator/brush problems. and it's
>> only pump problems on gear or scroll types.
>
> You are talking to the guy who designed and power limit-tested the
> EMI/RFI coils on a certain GM gerotor pump. Believe me: The wire was
> sized minimally for reliable life in fuel (for cooling) - 24 ga. solid
> copper magnet wire carrying approx. 5 amps. I also designed the plastic
> brush holder which also served as the motor/pump end cap. The "bearing"
> (bushing) on that end is merely a hole precision-molded into the
> plastic. The fuel is needed for lubrication for the bearings and shaft
> to last a reasonable period without the armature rattling around and
> crashing into the magnets. With fuel, bearing/shaft life is reasonable.
> Without fuel, it would not be. You would not get away with a metal
> shaft/plastic bushing bearing design on a windshield wiper motor -
> because of the lubrication, you can on a fuel pump.
>
> The powders that go into the molded brushes are specifically designed
> for use in gasoline. You would *not* use the same materials in the
> brushes for use in gasoline as for use in air. High current-density
> brushes (like in starter motors) have a *lot* of copper in them. Fuel
> pump brushes are almost pure carbon/graphite.
>
>>> Nice also to keep the two missing ingredient for explosions - oxygen
>>> and fuel vapors - away from the arcing of the brushes/commuator, eh?
>>>
>>>> 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.
>>>
>>> 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.
>>
>> 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.
>
>>>> 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.
>
> The motor itself (bearings, brushes, armature) would not last long
> without the fuel. The turbine fan of course has no solid-to-solid
> rubbing/wear so I'll give you that.
>
>>> I guess what you're saying is that Honda uses mostly or totally
>>> turbine pumps?
>>
>> 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.
>
> In general you may be right. However, there are some specific motors in
> very recent years that are extremely sensitive (in a negative way) to
> oil changes much beyond 3000 miles. Examples: Chrysler 2.7L, certain
> Toyota engines, and I believe certain Honda engines. Try running those
> on 10k miles change intervals, and they will totally sludge up and fail
> before 100k miles (typically 60-80k miles). I know almost nothing of
> the Toyota and Honda problems beyond what I read, but I am more familiar
> with the Chrysler 2.7L and its sludge/failure problems.
>
> As for running pump with fuel low in the tank, I was glad to see Ray O.
> point out that many pumps are actually positioned very high in the tank
> so that it is impractical to keep the fuel high enough to guarantee that
> they're submerged all the time. I suspected as much, but wasn't sure,
> so I kept quiet on that point - until today.
>
>> i understand that you cant force dumb people to be smart, but you can
>> sure encourage them to be silent!
>
> Bill Putney
> (To reply by e-mail, replace the last letter of the alphabet in my
> address with the letter 'x')


while informative, there's nothing new in what you say. the vast
majority of detroit's r&d over the last 20+ years has been into life
limitation, and everything you describe is entirely a part of that
process. the japanese otoh don't haven't had the same manufacturing
objectives, or at least, if they do have an end life in mind, it's an
order of magnitude further out than detroit's. [i think japanese intent
is to simply *bore* you into new sales with gross reliability rather
than bankrupt and disillusion which is how we do it.]

i think attributing detroit's faults to japanese vehicles is like
punishing your daughter because you caught your son smoking - somewhat
unjustified.

Re: Repeatedly Running On A Low Tank?
 

hachiroku wrote:
> On Mon, 02 Jun 2008 21:40:31 -0700, jim beam wrote:
>
>>>>> 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.
>>>> 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.
>
> When it comes between listening to you, or a former Toyota Factory
> Service rep, guess who wins?
> (HINT: it's not you!)
>
> You already proved how much you know with your 12,000 mile whether-it-
> needs-it-or-not oil changes...
>

get your facts straight - i'm not "whether-it-needs-it-or-not", that's
you with your 3k mile oil changes.

i've done the testing and /determined/ my change interval. real data
beats superstitious bullshit every time.