A different arrangement for fuel pumps (2025 Update)

Pumping air into gasoline vapors would be a bad idea (boom). especially in case of a crash. Maybe with a bladder.

Sounds like a good idea for us, bad idea for those who sell pumps.

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

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 :-))

Your point is??

What's hard about 8 easily acessible bolts, 4 simple screws and one electrical plug?

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.

1. Two fail items instead of one

- Ford's mid 80's system used the two-pump method

1. 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.

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.

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

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.

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....

S*it happens... some s*it happens before we expect and other s*it 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...

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.

How about using one of the older electric fuel pumps like an autopulse. 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.

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.

A simple myo-cranial in-fart-shun on my part...

Apologies!

{though I will keep my eye on you} ;)

Why some [trade] magazine hasn't hired you is beyond me.

I love it... dammit, Warman why dont you co-blog with me! would make it worth my time!

Look here...

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

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.

...

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

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.