A different arrangement for fuel pumps

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Backyard Mechanic wrote:

Nehmo - So there's a fuel pump timer? So how does it work and where is it? If the engine is off, the fuel pump only works for a minute or so? What happens when you try to re-start? Does it go for a minute or so again? And how does it know if the engine is running?
-- (||) Nehmo (||)
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Yes. It also solves the tank venting issues. The problem is that the failure modes in case of a tank leak or an accident are a lot worse than with an unpressurized tank.

My argument against this is that it's another attempt to use more electrical and mechanical stuff, which is prone to failure just because of the nature of electrical and mechanical things, to solve a problem caused by careless operators. I think that's usually a bad thing. --scott
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"C'est un Nagra. C'est suisse, et tres, tres precis."

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snipped-for-privacy@panix.com (Scott Dorsey) wrote:

Dont see why not... isnt that how our legislation in various governing bodies works?
Oh.... that's right, it IS how it works... never mind.
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Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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In our last episode, we saw our hero, Nehmo, laying in the sodden Kansas mud, various bits and pieces of his fuel system gathered about him..... The saga continues...
As the sky darkened and the gentle breeze gained passion, our hero's dog, Toto, moved closer...... after whizzing on the left rear tire.... suddenly, Nehmos world turned topsy turvy.....
As he regained equilibrium, our hero said "Oh, Wow, Toto.... we ain't in Kansas anymore..... I got the munchies....". And the two combined talents to design a fuel system that Rube Golberg would be jealous of..... after nehmo whizzed on the left rear tire....
Shit happens... some shit happens before we expect and other shit never happens..... In our modern world (spelled "mass production"), two seemingly identical items can be like night and day in regards to traits such as overall quality, general metallurgy, fit and finish and internal clearances.... These factors can have an effect on the life span of any component.
FWIW, my experience tells me that THE MAJOR cause of fuel pump failure is neglecting to change the fuel filter in a timely manner. If this truck has ever been run to the point where a restricted filter has given driveability issues, we can expect a premature fuel pump failure (even though we don't know how many miles or hours are on this nearly 6 year old pump).
If we have ever experienced the inconvenience of a flat tire, we don't set about designing cast iron tires.... If we have ever had a rock chip in a windshield, we don't come up with wire mesh guards....
As for introducing air into the fuel tank.... the motor on the electric pump uses a commutator and brush arrangement. As each commutator bar breaks contact with a brush, a spark occurs..... Your truck doesn't blow up because the fuel vapours in the tank are well above the UEL (upper explosive limit). If we introduce oxygen into this vapour rich environment, we can bring this mixture into the explosive range. And we are still left with the possibility of starving our newly positioned pump.
There is no real concern with allowing our fuel level to drop below 1/4 tank.... but should we allow the level to remain there? As temperature changes, so does the dew point.... condensation can settle on the inner walls of the fuel tank find it's way into the bottom of our fuel tank. Additionally, keeping the tank close to full means we have one less concern should we have the need to suddenly travel any distance... one less concern should we find ourselves in a position where we can't find a fuel source...
While I would imagine that most reading this have experienced a fuel pump failure in their lifetime, I doubt that you'll find many that have experienced multiple fuel pump failures. My last bad pump was on a car with a carburettor...
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Why some [trade] magazine hasn't hired you is beyond me.
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I love it... dammit, Warman why dont you co-blog with me! would make it worth my time!
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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Jim Warman wrote:
...

Jim, fuel pumps failed more often on carbed cars, but I've lost electric pumps on every FI Ford I've had except my '85, '89, '91, '98, & '01 Crown Vics... BUT I never drove those as much as my Taurii, Tempo, Aerostar. I think it's more to do with miles/hours(& the filter issue).
It was not unusual to replace a fuel pump every 40-50 K on carb cars when we drove less(that might have been 3 to 6 years) and didn't keep cars as long. Last carby car to need a fuel pump for me was an '82 LTD S(255 V-8, VV carb).
Rob
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I hate to even admit anything like this..... but the old 283, you could just about set your watch by when the fuel pump would calf.... and if you're old enough to remember the 283 as a current production engine, I feel for ya...
I have yet to personally experience a fuel pump failure on an EFI vehicle.... however, I do replace my fuel filters annually... this is part of what I expect to be my last service before the cold weather settles in. At this time I recheck my coolant strength and condition (we use a lot of test strips at work so that part is good... for personal use, remember that test strips have a "shelf life"), block heater operation, battery performance and so on... I have little patience for unexpected breakdowns - add that my loving bride is often placed in a position where she must travel a lonely highway in some pretty bad conditions alone.... There is a very real chance that some might consider what I do as "overkill".... at the same time, my operating costs (for what little bit I do track them) are very low... and my inconvenience factor and frustration level are miniscule.
Owning and driving any motor vehicle should at least be enjoyable... it can be if we realize that taking good care of our units involves planning and tools.... not Armorall and a rag...
I was chatting with another Harley owner just a few days ago..... he was busy chastising me because my bike doesn't really gleam in the sun.... As we parted company, he stalled his "spit 'n' polish" queen at least three times. I can't speak for anyone else... I bought my scooter to ride - not to polish.
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Jim Warman wrote:

Easy there pardner! You're talking about one of the all time great engines in the history of automobiles. My first set of wheels was a 64' Biscayne wagon with the venerable 283. Bought it used for $195 with 73K and drove it to well over 150K. I changed the fuel pump more than once (easy job) but I never had to do any major mechanical work on that engine. Eventually I had to take the 64' off the road because of a rusted frame, so I put the 283 into a 70' Belair wagon and drove it for several more years. I finally sold the engine when it was 16-years old for $200, which means I got my money back on the 64' wagon! Makes me tear up just thinking about it. ;-)
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Gotta get a zinger in here... SO WHAT DIFF does that make?
Never mind I also think the SB Chevy was the greatest V-8 ever designed and built (YES, over the Ford flathead!), doesnt change the fact that the fuel pump was prone to failure..

it was only an easy job after you learned the trick of axle-greasing the FP pushrod to hold it in place....Remember that?

Weel, that's alright, then.
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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Backyard Mechanic wrote:

The Ford flathead may have been the quietest V-8 I ever heard or didn't hear. I remember when my father's 53' Victoria was idling next to me and I couldn't hear the engine. I had to open the hood to see if it was really running! That engine also caused me some early teenage consternation when I received a Renwal 'Visible V-8' model engine kit for Christmas one year. I couldn't figure out why the kit didn't look like my father's 53' Ford V-8, particularly the location of the spark plugs in the heads. I didn't know about flatheads back then and also that 53' was the last year for the Ford flathead. The kit was a model of an OHV V-8 from the mid' 50's. :-)
http://www.vanpeltsales.com/FH_web/flathead_specs-90to125late.htm

Sure do. The FP pushrod used to slide out of the block unless you 'glued' it in with some heavy grease. Otherwise you had to be real quick with installing the pump before the pushrod fell out. BTDT :-) It also helped to have the engine rotated to the low point of the FP drive cam' so it wasn't applying any force on the pushrod and the pump's drive lever. If not, the spring tension on that lever had to be overcome while you were positioning the pump in the block hole.

I sometimes wonder if that old 283 is still running in someone's restored Chevy.
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Jim Warman wrote:

HA! HA! HA! Jim you missed your calling. Or do you have a comic writing job on the side? Not to get too picky here, but.......Kansas City is built on the Kansas/Missouri state line. About 3/4 of Kansas City is in the state of....(drum roll please)...... MISSOURI !!!!! I think there is an 1886 Kansas law that outlaws overengineered Nehmos, so maybe we are safe here. Also, I've got a 300K mile '88 Cougar that I've replaced the fuel pump on 3 times, so it's had 4 fuel pumps in it's life, so far. 'Course, maybe I use crappy fuel pumps, I don't know.......
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Nehmo wrote:

My race car works this way, but it runs on methanol. I'd be hesitant to use it with gasoline because of the explosion hazard with gasoline. In a crash the fuel may spray all OVER the place.

That SUCKS fuel through the fuel line. You might have to take an old tank pump and remove valves and stuff, but the autopulse may suck through the in-tank pump and be mounted on firewall.
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You are way, that's WAY, over engineering this thing. Or way over thinking it at the very least.
I have an '81 Jeep CJ5 that I converted from a crappy carburetor system to multi port fuel injection. the fuel pump for the MPFI is external to the tank, and connects to the pick up that the old mechanical pump was hooked up to. The electric fuel pump sucks gas from the tank, pulls it through a filter, then pumps it to the injector rail. No need for pressurized air to get the pump going. Replacement is easy, well that's relative I suppose. All I need to do is raise the vehicle by the frame so the rear axle drops, and I can get to the fuel pump without much trouble.
I see no reason why the Ranger could not be fitted with an external fuel pump. Having said that, the internal pump has several operational advantages, and if you keep gas in the tank, it should last a very long time. The gas acts as a coolant, drawing heat away from the pump and dissipating it. The need to replace an in-tank fuel pump is often associated with running the gas to the bottom before refills. Yes, there can be other causes, but you can control the fuel level easier than you can control the other causes.

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Look here...
http://www.mkiv.com/techarticles/fuel_pumps_test_2/fuelpumpdiagram.gif
As shown the fuel flows THROUGH the motor. Thus pump will only overheat if there's no fuel flowing. and if other electronics are right, it wont run long if there's no fuel to flow.
While the low-tank syndrome applies regarding sporadic flow, once the engine doesnt get enough pressure, it will stop, and then the Fuel Pump will stop, as well
Solution, dont worry too much about maintaining 1/4 tank...DO gas up when the needle hits 'E' or low-fuel lite comes on
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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Another flip side, BYM.... my loving bride is the "gasser upper" for the "good" truck..... she hates to get below a half (can I make it to the store???).... But, I find it much easier to gas up when I have the urge to gas up rather than have to break into a cold sweat about it.
I keep harping on "convenience" factor... if we do things when it is convenient for us to do them, we are never worried about having to do things when it is inconvenient. So what if I have half a tank? Theres the pump island, a soda would be nice, might as well do "the nasty" and be done....
Now, I realize that there are a lot of people out there that aren't "driven".... but, for some, there is much to be said about simply getting our fat asses out of the desk chair and "doing something"... which I must do directly.... with warm weather, I want to finish the framing in my addition so I can get the inspector in. I went to work about 11PM last night and yanked the transmission out of an ambulance (nothing good on TV, anyway) and later today, if I can find someone to help lift, I can get the replacement trans on to the jack and get it in by tonight.... and even have time to "Q" some burgers in between...

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Nehmo wrote:

Work? Yes. Needed? No. Further, you would have to take care to filter the "blown" air. A pressurized tank would need to be carefully designed to be opened for filling without "burping" gasoline (pressure release before openning). A pressurized tank might be considered a higher explosion hazzard.
The existing design is meant to reduce cost of manufacture. These pumps usually don't die for the lifetime of the vehicle. You're unlucky, that's all.

They could use a more simple detection method in the fuel line or the pump itself. I agree on this as my SO killed her fuel pump recently after the second time she ran out of gas (because the gas guage indicated nearly 1/2 full when in fact it was empty). Crappy Chevrolet.
Cheers, Alan
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