Re: In-the-tank fuel pumps cause death and destruction

VW beetle had the gravity feed. Not sure that I'd want a gravity feed if I was involved in an accident....... ;-)

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

Denny

I have found many locknuts on the vehicles I have, seems they use them where necessary. Some new cars you don't have to drop the tank. I found an Impala web site and the site owner did several how-to's from changing wiper blades to the fuel pump. In the Impala you remove the back seat and then there is a access panel that you remove and then you can pull the pump out from there. I assume other cars would be the same.

Actually, yes, yes I would! I could use the royalty payments on my patent... :-)

Oh, come on, I'm sure you can! :-)

Matt

uel_pump/

I replied to another part of the thread already but will repeat here that the car my wife owns (2001 Impala) has an access door under the rear seat. Pull the seat and then unbolt the access door/cover and you can then remove the pump.

Yes, and if you don't use the drain fairly often, it will be so corroded by the time you need it that it will likely just snap off anyway causing a situation more dangerous than not having it to start with. Someone earlier mentioned the comparison to airplane fuel drains. This is a completely bogus analogy for at least two reasons:

1. The airplane drains are used before EVERY flight (or at least should be). This keeps them in good working order, at last until the seals get back and they start to seep, but then you replace the seals.
2. Airplanes aren't exposed to the road salt and other nasty stuff that the underside of a car sees.

Matt

Actually, their isn't. Water doesn't mix with either.

Matt

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.

Yup, works great with a truck. Now do that on a mini-van. Try that on a LHS.........

I believe the original poster said transfer pump, not the car's fuel pump. That method would work just fine.

Matt

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.

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

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

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.

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

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')

The average automotive OEM not a aftermarket high flow pump is 19 to 30 GPH ( Gallons per hour ) not the advertised GPH of the high performance pumps on the first page of your google search. Pumps as a rule do not deliver the maximum advertised GPH when plumed in. There are a lot of reasons for this. One of the biggest is the size and lengths of the lines the pump must push the fluid through. The same holds true for the supply side of the pump. The amount of restriction in the filter must also be considered. You will never see the pumps rated flow, especially through the very small opening of the Schrader valve. But for argument sake the highest average for OEM is 30 GPH, is a max of 15 gallons in 30 minutes, if there is no restriction involved, but we know there is.

I routinely fill 2 and 5 gallon fuel cans for my home power equipment via the fuel pressure Schrader valve. It takes roughly 7 minutes to fill the 2 gallon can. So 3.5 minutes ( for one gallon ) x 19 gallons is 66.5 minutes. The pump is new, well less than a year old. I can shave a about a half a minute if I remove the Schrader valve core. 3 x 19 = 57 minutes.

Point noted, some vehicles are built this way, but only a small number. The vast amount of vehicles require the dropping of the tank, unless one wants to cut a hole in the floor.