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Re: Repeatedly Running On A Low Tank?
Daniel Who Wants to Know wrote:
> All that being said I have also personally heard the distinct sound of vapor > bubbles going through the fuel pressure regulator on a car with the engine > running. I think in some cases the pump starts sucking air through the top > of the pickup sock before the tank is completely empty but yet is still able > to supply enough pressure and volume for the engine to run. I can visualize that happening as it starts sucking bubbles of air rising into the pump thru the pickup tube. Kind of like cavitation, except air instead of nothing. Froth. 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?
Elle wrote:
> ...E.g. climates that have a lot moisture in the air > will tend to promote more rust in the fuel tank than if the > climate were dry... Not that much of a problem these days with sealed tanks. > From talk on the net, it does seem to me that debris > accumulating at the bottom of fuel tanks is not uncommon. > And why have a fuel filter whose changing is prescribed to > be every few years, besides, if the debris is no concern? So > too do we see reports of fuel tanks failing... FWIW, Chrysler LH cars have life-of-vehicle fuel filters, and apparently they are effective (very few posts on LH forums for fuel filter issues). > I do not think the OP's article is baloney. It's just > suggested best operating practices to minimize fuel system > problems, ISTM. Not a big deal. I do not agree that the article is not baloney, but I agree that it's not a big deal. 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
> I can visualize that happening as it starts sucking > bubbles of air rising into the pump thru the pickup tube. > Kind of like cavitation, except air instead of nothing. > Froth. I trust you will recall that cavitation is not bubbles filled with nothing. It is the occurrence of bubbles filled with the vapor of the liquid being moved. It is a consequence of the liquid reaching a pressure low enough to cause boiling. |
Re: Repeatedly Running On A Low Tank?
Elle wrote: snip > > 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. > Honda Civics went to electric pumps beginning with the 1980 model year but it was external right outside the tank. I have never heard of a fuel pump failure with these units. Even after setting idle for nearly 12 years, the one in my '83 works perfectly. JT |
Re: Repeatedly Running On A Low Tank?
Elle wrote:
> "Bill Putney" <bptn@kinez.net> wrote >> I can visualize that happening as it starts sucking >> bubbles of air rising into the pump thru the pickup tube. >> Kind of like cavitation, except air instead of nothing. >> Froth. > > I trust you will recall that cavitation is not bubbles > filled with nothing. It is the occurrence of bubbles filled > with the vapor of the liquid being moved. It is a > consequence of the liquid reaching a pressure low enough to > cause boiling. You are correct. 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?
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... |
Re: Repeatedly Running On A Low Tank?
On Mon, 02 Jun 2008 18:20:56 +0000, Daniel Who Wants to Know wrote:
> P.S. Why is this cross posted to about a zillion newsgroups? 'Cause the OP did to begin with. |
Re: Repeatedly Running On A Low Tank?
"Bill Putney" <bptn@kinez.net> wrote
> Elle wrote: >> ...E.g. climates that have a lot moisture in the air will >> tend to promote more rust in the fuel tank than if the >> climate were dry... > > Not that much of a problem these days with sealed tanks. Bill, the article is addressing all the saps too poor to keep their gas tanks full. You really think they're all driving cars with a model year later than about 1998, when fuel tanks were going plastic? :-) (I am just guestimating the year plastic became really popular, based on googling on the subject.) |
Re: Repeatedly Running On A Low Tank?
"Grumpy AuContraire" <Grumpy@ExtraGrumpyville.com> wrote
> Elle wrote: >> 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. > > > Honda Civics went to electric pumps beginning with the > 1980 model year but it was external right outside the > tank. How'd you know this little factoid so quickly?! I believe you, just saying that's way inside information. > I have never heard of a fuel pump failure with these > units. Hm, unless you worked on Hondas of that vintage for a few years, I am not sure I can support a hypothesis that pumps of this vintage do not fail. > Even after setting idle for nearly 12 years, the one in my > '83 works perfectly. Yeabut you don't run to empty/"on fumes" (as they say), do you? Those of you attesting that the article's thesis is bunk may be right. Just saying fuel pumps do fail; more authoritative sources than Fox make the same claim the Fox article does (which is pretty darn general; look back); and those of you saying, 'Ain't never seen a fuel pump failure in my guzillion years of drivin' ' just do not run the car to empty enough or do not leave your fuel filter unchanged long enough to have a problem. |
Re: Repeatedly Running On A Low Tank?
Elle wrote:
> ...Just saying fuel pumps do fail; more authoritative > sources than Fox make the same claim the Fox article does > (which is pretty darn general; look back);.. As time goes on, I believe lees and less of what I read because much of what I see reported that I have first-hand knowledge of I know to be absolute b.s. > and those of you > saying, 'Ain't never seen a fuel pump failure in my > guzillion years of drivin' ' just do not run the car to > empty enough or do not leave your fuel filter unchanged long > enough to have a problem. My '99 Concorde just rolled over 200k miles - original fuel filter (as it is designed to last the life of the car), and I routinely run it as low as it will go before filling up on my 80 mile daily commute - almost always between 3/16 and below 'E'. Yeah - I know - a sample of one. But that is lifelong habit - have never had a fuel pump fail in over 40 years of driving/DIY'ing. 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
> 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 ハチク 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? |
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