A different arrangement for fuel pumps

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As faithful readers of my posts know, I'm changing the fuel pump on my 2001 3.0L Ford Ranger. I currently have the gas tank removed, and the pump replaced in its assembly, but I don't yet have the pump assembly
back in the tank. It began to rain here in Kansas City, so I couldn't really proceed. It's dark now too.
But I was wondering: Since the in-the-tank placement makes this pump a chore to replace, isn't another design possible? What about sending pressurized air into the tank, and at the bottom of the tank have a pick-up tube for the fuel. The fuel (forced out the tube by the air) could then be additionally pressurized by outside-the-tank pumps. Wouldn't this two-stage process work?
Also, in the existing in-tank placement, since running out of gas hurts the pumps by depriving the pump of coolant (the fuel), why not have a cut-off switch that works by the float? There is a float on a leaver in the pump assembly, but it doesn't look like it does anything electrical for the pump. I think it's the fuel level sensor for the instrument panel gauge. A fail-safe circuit could be designed to work with this sensor. When the level gets too low, the pump could turn off. -- (||) Nehmo (||)
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an ingenious person can do anything.The auto makers sell more parts and service by making things (harder)more cost efficient old john
Hello, Nehmo! You wrote on 22 Apr 2006 22:04:37 -0700:
N> But I was wondering: Since the in-the-tank placement makes this pump a N> chore to replace, isn't another design possible? What about sending N> pressurized air into the tank, and at the bottom of the tank have a N> pick-up tube for the fuel. The fuel (forced out the tube by the air) N> could then be additionally pressurized by outside-the-tank pumps. N> Wouldn't this two-stage process work?
N> Also, in the existing in-tank placement, since running out of gas hurts N> the pumps by depriving the pump of coolant (the fuel), why not have a N> cut-off switch that works by the float? There is a float on a leaver in N> the pump assembly, but it doesn't look like it does anything electrical N> for the pump. I think it's the fuel level sensor for the instrument N> panel gauge. A fail-safe circuit could be designed to work with this N> sensor. When the level gets too low, the pump could turn off.
With best regards, snipped-for-privacy@comcast.net. E-mail: snipped-for-privacy@comcast.net
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snipped-for-privacy@comcast.net wrote:

Your point is??
What's hard about 8 easily acessible bolts, 4 simple screws and one electrical plug?
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Nehmo wrote:

OK. First, you're not supposed to constantly run the vehicle low on fuel. Do you just fill to 1/4 tank at a time? If not, overheating of the pump is not an issue. As far as your two stage design, it would add unnecessary complexity and parts to the fuel system. As for the complexity of replacing the pump in your Ranger. Did it ever cross your mind to remove the 6-8 bolts in the bed (along with 4 screws for the filler neck and one electrical connector for the rear lamps), then slide the bed back, and do the pump right there in front of you (with lots of room to lay tools, fasteners, your beverage, and even your lunch if it's that time of day)? Think the project through sir!! It's 3 hours IF you break for lunch.
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I guess he was to busy re-designing his fuel system :-)
By pulling the bed it's a 3 hour job if you break for lunch AND do your lunch nap :-))
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Tom Adkins -

Nehmo - We've had the truck for less than a year, and naturally I don't know the fueling practices of the previous owners. But yes, there's several occasions we've ran it to less than a quarter of a tank, and I did run out of gas recently. But I don't think our fueling practices are that unusual.
Some people have told me that running out of gas could have been what killed the pump, and that Rangers are vulnerable in that respect. If they indeed are, then there should be a cut-off. It would be a simple mechanism to add.
Tom Adkins -

Nehmo - Well, yes, I did think of that, but I never did the job before, so out of caution I went with Chilton's advice, which was the remove-the-tank route. Have you done it by taking off the bed? -- (||) Nehmo (||)
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Nehmo wrote:

Yes, I always pull the bed to do a fuel pump on a Ranger or F-Series truck. The first thing you should do is use the Chilton manual to start your next bonfire. It will serve a much better purpose. Then get the OEM ford manuals for the truck. Yes, even the Ford manual states to remove bed to R&R the fuel pump. But think about the task at hand!! How hard is it to unsecure the bed and slide it back?? as opposed to removimg the tank shield, straps and tank? A manual is no replacement for rational thinking. You are working on a truck (or car), not doing brain surgury.
As far as your fuel pump, running it dry a couple of times will not guarantee a failed pump, nor are Ford Rangers more suceptible to pump failures. Ford used the same pump across their vehicle lines. Over the years there were design changes that made certain pumps more failure prone but they crossed model lines and were not model (Ranger)specific. The pump is cooled, by design of the fuel system, by the fuel flowing through it. Once the fuel stops flowing though the pump the engine stops running, thus so does the fuel pump. The amount of fuel outside of the pump has minimal bearing on pump life.
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Tom Adkins -

Nehmo - Is there something that makes the pump stop when the engine quits? The ignition switch would still be in the run position until the driver makes the change, and the driver, perhaps in desperation, may try repeatedly to start.
And I'm a little upset the Chilton gave misleading advice. Maybe there's some logic to their recommendation. You would think those guys knew what they were doing.
The section I used was from the online version. Here's a copy: http://home.kc.rr.com/plumb/32077_rang_5_1.html Scroll down to the Fuel Pump part. It's brief. [If anybody wants this, copy it rather then bookmark it. It won't last on my ISP provided space.]
-- (||) Nehmo (||)
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Nehmo wrote:

When I went to remove the bed on my truck, not one bolt came out. They either snapped or spun the nut inside the frame....
I sure wouldn't try that on a 6 year old vehicle up here in the rust belt, nor would I recommend it.
Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id !15147590 (More Off Road album links at bottom of the view page)
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I think the last thing one would want to do is put positive pressure in the fuel tank. In the event of a puncture rapid fuel loss would be assured. In the event of a collision, this could make the tank sort of a flame thrower. All of that aside, the tanks are vented to the emissions control system. They are designed so siphon off gasses to the EC system. Adding positive pressure to the system would really play hobb with that set up. My take: pull the bed. I've had two Rangers and driven each a combined total of 300K plus miles. Neither had a fuel pump problem. You have just been unfortunately unlucky.
--
R. J. Talley
Teacher/James Madison Fellow
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They may not be that unusual, but they are damaging to the fuel delivery system.

That's why they added a fuel guage, so you could monitor the status of the remainig fuel load.
In all fairness to you, I would not have thought of taking the bed off to gain access to the fuel tank and pump.
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Jeff Strickland -

Nehmo - I finished the pump replacement, and the truck runs... but...
After I got everything back together, I idled the truck for several minutes. I checked for leaks and couldn't find any. I drove down the alley and the truck died a couple hundred feet away. Looking out the window, I saw a rapidly increasing wet spot on the pavement, and this meant I was bleeding from an artery. Further inspection revealed the 90 elbow connector on the top of the tank was the culprit.
My first attempts to reach my hand to the elbow were unsuccessful, and I was contemplating the remove-the-bed technique. But then this time if I dropped the tank, I wouldn't need to do it all the way. I could get to the elbow by just dropping the rear of the tank. Anyway, while I was weighing the alternatives, I jacked up the left side of the frame and gained enough reach to push down on the elbow. It seemed to work. I only drove to the nearby gas station and back, but it didn't leak again.
I'm thinking about drilling a hole in the bed so that I can use a rod to get a good push on that connector. Maybe I damaged it when I disconnected it. It has a green button in a slot that you press to release. I thought it snapped in position when I connected it the first time; maybe it didn't.
This connector is on one of the lines that goes to the fuel filter. Maybe I'll have to replace that line.
Before I sign-out for the night, thanks everybody. I truly appreciated your help.
-- (||) Nehmo (||)
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1. Two fail items instead of one - Ford's mid 80's system used the two-pump method
2. Pressurized air into the tank. - Interesting concept... Can we say "Stoichometric?" Heh Cant even type it... suffice to say, get your such-equipped vehicle under cover in event of lightning storms... and pray your Fuel level sending line doesnt short out.
--
Yeh, I'm a Krusty old Geezer, just helpin' with the brainstorming

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Nehmo wrote:

Faithful readers of your posts???? A bit presumptuous on your part to think you have an audience of the faithful.

Why not just replace the original pump with another factory unit. Did the pump really die on a 5 year old car?

Sounds like a good idea. Just run a hose to the drivers seat and blow on it periodically.

If you are worried about that issue why not try the simple 100% effective solution - keep the gas tank over 1/4 full.

Sounds like a project for someone with a lot of time on his hands.

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Which would reduce the effective capacity of the tank... wooden it!
Already a fail-safe built in, the engine stops.. and since it's not turning, the FP timer times out and fuel pump stops as well.
Ingenious, no?

Here we go again... While it may help to not leave the pump body exposed most of the time, look closely at the pump construction. It's cooled by the fuel it pumps, not the fuel surrounding it.
IOW... dont run it empty. Dont run the pump for any length of time without engine running/fuel flowing.
--
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:

Consider posting responses under the message they pertain to.
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Come again? What are you talking about?
I'll be less cryptic than you... Since I hit reply in the thread and addressed quoted comments in the topic, how did I screw the thread up?
Waiting....
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Backyard Mechanic wrote:

someone else, possibly the original poster. You will stand a greater chance of having someone understand the context of your messages if you send them to the correct person.
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Uh.. yeah, which is why I apologized immed, next post
Again.. my bad.
--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!
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A simple myo-cranial in-fart-shun on my part...
Apologies!
{though I will keep my eye on you} ;)
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