In-the-tank fuel pumps cause death and destruction

On Sat, 30 Oct 2004, Thomas Moats wrote:

>>>> totally unmonitored, so you can do another job while it is being
>>>> drained. The schrader valve is removed to remove a significant amount
>>>> of restriction from the line.

>>> That is bull.

>> Actually, no it's not. It works great as long as you have a working
>> fuel pump.

> If your fuel pump is working why would you would you drain it that way?
> It is very time consuming. You will not pull 72 liters or 19 gallons in
> a half hour.

Are you sure? Let's do a little math. A quick Google on "electric fuel
pump" gph shows us automotive pumps with volume flowrates of from 43 to
220 gph on the first page alone. Take the lowest-rated one (43 gph). Half
of 43 gallons per 60 minutes is 21.5 gallons per 30 minutes.

On Sat, 30 Oct 2004, Thomas Moats wrote:

>>>> totally unmonitored, so you can do another job while it is being
>>>> drained. The schrader valve is removed to remove a significant amount
>>>> of restriction from the line.

>>> That is bull.

>> Actually, no it's not. It works great as long as you have a working
>> fuel pump.

> If your fuel pump is working why would you would you drain it that way?
> It is very time consuming. You will not pull 72 liters or 19 gallons in
> a half hour.

Are you sure? Let's do a little math. A quick Google on "electric fuel
pump" gph shows us automotive pumps with volume flowrates of from 43 to
220 gph on the first page alone. Take the lowest-rated one (43 gph). Half
of 43 gallons per 60 minutes is 21.5 gallons per 30 minutes.

On Fri, 29 Oct 2004, Bill Putney wrote:

> Matt Whiting wrote:
>
> > How many cars have you heard of that have exploded or caught fire from
> > an in-tank fuel pump? In my case, the answer is zero so I don't lose
> > much sleep over it.
>
> Well *sure* you say that *now*. But would you have wanted to be the
> first engineer in history to propose doing that? 8^)

I'd have no qualms being that engineer, and here's why: Gasoline is
combustible in only a narrow ratio range with air. Bored suburban kids
used to get empty paint cans from the hardware store, put a barbecue
sparker with long leads in the side of the can, use an eyedropper to put
two drops of gasoline in the can, hammer on the lid, stretch the sparker
leads and hit the button to cause a loud noise and a flying can lid.

One drop of gasoline didn't work. Three or more didn't work. TWO drops --
and only two drops -- worked.

The ratio of fuel to air is always much too high (or, if you prefer,
the ratio of air to fuel is always much too low) for these hallucinatory
panoramas of firy death some people (even engineers, amazingly enough)
have been talking about in this thread. That's why they don't happen.

DS

On Fri, 29 Oct 2004, Bill Putney wrote:

> Matt Whiting wrote:
>
> > How many cars have you heard of that have exploded or caught fire from
> > an in-tank fuel pump? In my case, the answer is zero so I don't lose
> > much sleep over it.
>
> Well *sure* you say that *now*. But would you have wanted to be the
> first engineer in history to propose doing that? 8^)

I'd have no qualms being that engineer, and here's why: Gasoline is
combustible in only a narrow ratio range with air. Bored suburban kids
used to get empty paint cans from the hardware store, put a barbecue
sparker with long leads in the side of the can, use an eyedropper to put
two drops of gasoline in the can, hammer on the lid, stretch the sparker
leads and hit the button to cause a loud noise and a flying can lid.

One drop of gasoline didn't work. Three or more didn't work. TWO drops --
and only two drops -- worked.

The ratio of fuel to air is always much too high (or, if you prefer,
the ratio of air to fuel is always much too low) for these hallucinatory
panoramas of firy death some people (even engineers, amazingly enough)
have been talking about in this thread. That's why they don't happen.

DS

Al Smith wrote:

> Wait a minute. Maybe there are shortcuts in some cases - and I have
> only done
> it once - but every fuel pump replacement I have heard about
> involves dropping the tank.

Well, I suppose this means that you haven't heard about enough
of them then. Even with dropping fuel tanks, most of them are not
nearly as hard as you might think. You are comparing replacing
an electric fuel pump that is "outside" the fuel tank to replacing
one that is inside the fuel tank. I was thinking more along the lines
of the older mechanical fuel pumps that were attached to the engine.
These were far more common on domestic vehicles then inline
external electric fuel pumps.

Many late model vehicles also have access panels in the trunk that
make changing an electric fuel pump a 15 minute job. Most vehicles
that I work on (GM), you can have the fuel tank out in 10 minutes.

Ian

Al Smith wrote:

> Wait a minute. Maybe there are shortcuts in some cases - and I have
> only done
> it once - but every fuel pump replacement I have heard about
> involves dropping the tank.

Well, I suppose this means that you haven't heard about enough
of them then. Even with dropping fuel tanks, most of them are not
nearly as hard as you might think. You are comparing replacing
an electric fuel pump that is "outside" the fuel tank to replacing
one that is inside the fuel tank. I was thinking more along the lines
of the older mechanical fuel pumps that were attached to the engine.
These were far more common on domestic vehicles then inline
external electric fuel pumps.

Many late model vehicles also have access panels in the trunk that
make changing an electric fuel pump a 15 minute job. Most vehicles
that I work on (GM), you can have the fuel tank out in 10 minutes.

Ian

"Matt Whiting" > wrote in message
...
> Thomas Moats wrote:
>
> > "Denny" > wrote in message
> > ...
> >
> >>"Thomas Moats" > wrote in message
> ...
> >>
> >>><snip>
> >>>
> >>>>>If you have about a week to wait for the fuel to tranfer........
> >>>>
> >>>>No,, about half an hour maximum will empty a 72 liter tank - and
> >>>>totally unmonitored, so you can do another job while it is being
> >>>>drained. The schrader valve is removed to remove a significant amount
> >>>>of restriction from the line.
> >>>>
> >>>>>
> >>>>><snip>
> >>>>>
> >>>That is bull.
> >>>
> >>>
> >>
> >>Actually, no it's not. It works great as long as you have a working fuel
> >>pump.
> >>
> >>Denny
> >>
> >>
> >
> > If your fuel pump is working why would you would you drain it that way? It
is
> > very time consuming. You will not pull 72 liters or 19 gallons in a half
hour.
> >
> >
>
> I believe the original poster said transfer pump, not the car's fuel
> pump. That method would work just fine.
>
>
> Matt
>
Yes he was referring to a transfer pump. Even with a transfer pump, he will not
remove 19 gallons or 72 liters in a half an hour. The lines are too small in
diameter. There is restriction from both the pump in the tank and fuel filter.
Then once the return line is no longer under fluid the possibility of sucking
air if the regulator is of an open center design. Which means you can no longer
pump fluid.

"Matt Whiting" > wrote in message
...
> Thomas Moats wrote:
>
> > "Denny" > wrote in message
> > ...
> >
> >>"Thomas Moats" > wrote in message
> ...
> >>
> >>><snip>
> >>>
> >>>>>If you have about a week to wait for the fuel to tranfer........
> >>>>
> >>>>No,, about half an hour maximum will empty a 72 liter tank - and
> >>>>totally unmonitored, so you can do another job while it is being
> >>>>drained. The schrader valve is removed to remove a significant amount
> >>>>of restriction from the line.
> >>>>
> >>>>>
> >>>>><snip>
> >>>>>
> >>>That is bull.
> >>>
> >>>
> >>
> >>Actually, no it's not. It works great as long as you have a working fuel
> >>pump.
> >>
> >>Denny
> >>
> >>
> >
> > If your fuel pump is working why would you would you drain it that way? It
is
> > very time consuming. You will not pull 72 liters or 19 gallons in a half
hour.
> >
> >
>
> I believe the original poster said transfer pump, not the car's fuel
> pump. That method would work just fine.
>
>
> Matt
>
Yes he was referring to a transfer pump. Even with a transfer pump, he will not
remove 19 gallons or 72 liters in a half an hour. The lines are too small in
diameter. There is restriction from both the pump in the tank and fuel filter.
Then once the return line is no longer under fluid the possibility of sucking
air if the regulator is of an open center design. Which means you can no longer
pump fluid.

Al Smith wrote:
> I may have missed it earlier, but it is your opinion that
> money had a lot / a little / nothing to do with the design?

A lot. What else is there (in modern business thinking)?

> Cost of repair was not a consideration?

Having worked in the industry for 7 years, I believe that the primary
driver for designs is intial cost to the mfgr., whether in the form of
parts cost or assembly labor. *IF* it can be determined that making
repairs easier and cheaper will help the mfgr.'s bottom line (i.e., if
the buying public becomes painfully aware of the extra cost of ownership
due to a poor design), then that may influence the design. In
MBA-think, if it hurts the customer or costs the customer money, but the
customer never recognizes that to the point of affecting buying
decisions, then there is no value added in making the design better. No
matter how it's sugar coated, in reality, the term "value-added" means
"it improves our profits". IOW, if it is an improvement (for the
consumer), but doesn't ultimately help the bottom line, then it isn't
"value added" (in MBA-think).

Possibly if it is considered to be a high rate of warranty repair item,
then that might be factored in too. But I believe in this case, the
prime motivator was total initial cost to the mfgr. IMO...

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


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Al Smith wrote:
> I may have missed it earlier, but it is your opinion that
> money had a lot / a little / nothing to do with the design?

A lot. What else is there (in modern business thinking)?

> Cost of repair was not a consideration?

Having worked in the industry for 7 years, I believe that the primary
driver for designs is intial cost to the mfgr., whether in the form of
parts cost or assembly labor. *IF* it can be determined that making
repairs easier and cheaper will help the mfgr.'s bottom line (i.e., if
the buying public becomes painfully aware of the extra cost of ownership
due to a poor design), then that may influence the design. In
MBA-think, if it hurts the customer or costs the customer money, but the
customer never recognizes that to the point of affecting buying
decisions, then there is no value added in making the design better. No
matter how it's sugar coated, in reality, the term "value-added" means
"it improves our profits". IOW, if it is an improvement (for the
consumer), but doesn't ultimately help the bottom line, then it isn't
"value added" (in MBA-think).

Possibly if it is considered to be a high rate of warranty repair item,
then that might be factored in too. But I believe in this case, the
prime motivator was total initial cost to the mfgr. IMO...

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


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