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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 ハチク 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') |
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