Looking for the inverse of a fluid solenoid.

[MarkT]

Not sure what to call this for searching on the net.  I'm installing a belly tank on Jade ('97 Tourer).  Per Joshcornkid, I'm changing how it's plumbed and wired.  Got the report from Dick, his fuel pump has failed 3 times.  At $50 a pop.  The way it's set up, the fuel pump runs all the time, while the main tank drains to the belly and the belly fuel pump sends it to the fuel rails.  I'm going to change it so the fuel is delivered by the main tank just like OEM (but with a Dan-Marc installed), and when the tank hits reserve, have the belly tank pump it's 3 gallons up to the main.  However I don't want to run the pump past the full delivery of the 3 gallons.  Not sucking air, IOW.  So not using just a toggle, or a switch with timer.  Want to hit a pump switch, have the gas available be verified, and then have the pump shut off when the belly tank is drained.  So I need something to sense the fuel at the pickup, and act as a relay or at least have an electrical signal that I can use to trigger a relay.  Any ideas?  Prefer not to use a fuel level sensor (like the IS gas sending unit) if I don't have to - want something more robust and w/o moving parts. Somebody here probably is involved with fluid handling and knows about this.  What do aircraft do with multiple tanks?  Can't all be gravity.

[Paladin528]

Why not just find a better pump?  the fuel pump on my ACE Tourer lasted to 96000 km and for all I know is still running strong.

[rhinor61]

Mark, I run the belly tank and I had no issues with the recommended set up.
But to answer your question.
I would use a latching relay with a fuel pressure switch installed on the fuel line going up from the belly tank to the main tank.  So when the fuel pressure drops off, it shuts off the fuel pump by breaking power to the latching relay..

Finding a pressure switch to go down to 1.5 psi maybe an issue..
https://www.pegasusautoracing.com/productdetails.asp?RecID=2980
is 2 to 7 psi..

You could do a timer, but that is risky. either by leaving gasoline in the tank or pumping air for a length of time.

You could just T- in a fuel pressure gage on the belly tank line.. turn on the pump, when the psi drops shut off the pump..

let me know what you find out..

John

[MarkT]

Mark, I run the belly tank and I had no issues with the recommended set up.
But to answer your question.
I would use a latching relay with a fuel pressure switch installed on the fuel line going up from the belly tank to the main tank.  So when the fuel pressure drops off, it shuts off the fuel pump by breaking power to the latching relay..

Finding a pressure switch to go down to 1.5 psi maybe an issue..
https://www.pegasusautoracing.com/productdetails.asp?RecID=2980
is 2 to 7 psi..

You could do a timer, but that is risky. either by leaving gasoline in the tank or pumping air for a length of time.

You could just T- in a fuel pressure gage on the belly tank line.. turn on the pump, when the psi drops shut off the pump..

let me know what you find out..

John

That's useful info.  RM is using a Facet Purolator P/N 40178, specs on that say pressure max/min is 3.5/2.0.  Kinda on the edge of the envelope, might not be reliable if installed w/o some tweaks.  I'll look around for low pressure switches.

[3W-lonerider]

I seriously don't think a pressure switch is going to answer your problem.
mainly because there isn't going to be any pressure just from pumping fuel from one tank to another.
now what might work if you wanna go this route is a Honda oil sensing switch.
if you look at all small Honda engines for mowers, saws, concrete and mortor mixers.
you'll see a switch mounted low in the crank case. the way this switch works is. the ground runs threw this switch. if the engine oil gets low enough that the switch is no longer submerged in oil it goes open and removes the ground from the ignition. in most cases the way they have that switch in there you have to split the case to replace it. but you may be able to find one that screws in. if you mount it say within 1 inch from the bottom of the tank then run the ground threw this switch to the ground on the relay it will remove the ground from the relay when the gas drops below the switch. and cuts the relay out.

[BigMac (SoCal)]

My belly tank is plumbed the way you want yours. I have never had any problems with running the pump emptying the tank. What I did is when I got the tank installed I ran the pump with a full belly tank until it was dry. You can tell by the way the pump sounds when it's not pumping fuel. I takes 9.5 minutes from full to pump it all to the main tank and now and then I have forgotten about it for as much as 15 minutes with no ill effects on the pump. I wouldn't worry about it. If you have any questions let me know.

Dave
bigmac1520@verizon.net

 

[MarkT]

My belly tank is plumbed the way you want yours. I have never had any problems with running the pump emptying the tank. What I did is when I got the tank installed I ran the pump with a full belly tank until it was dry. You can tell by the way the pump sounds when it's not pumping fuel. I takes 9.5 minutes from full to pump it all to the main tank and now and then I have forgotten about it for as much as 15 minutes with no ill effects on the pump. I wouldn't worry about it. If you have any questions let me know.

Dave
bigmac1520@verizon.net

 

Honeywell makes a low pressure switch, 1.1-3.0 psi.  I have one ordered from Grainger. Dave - can you describe your plumbing?  I might not be thinking of this right; it seems much more complicated than maybe it is.  Thx

[di1213]

I installed a 2 gallon tank in a saddlebag, kept it simple with a "t" in the original fuel line then a hose going to low priced fuel pump mounted on the aux tank. put a switch under the fuel knob to operate the pump. I run on the bikes tank til I start running out then flip the switch. the two gallons will supply the carbs and excess would fill the bike tank. When the aux tank runs dry the pump will pump air and the bike will start to sputter and I know to flip the switch off. Crude but the set-up got me through some long streches. One drawback is I have to remember to make sure the switch is off when refueling or I'll get some spillage from the bike tank getting over filled.

[BonS]

A pump draws more current when free flowing (or sucking/pushing air) so you might be able to sense when the pump runs dry by sensing the current and shut it off automatically when it exceeds a preset threshold.

[Paladin528]

Why not T in the belly tank with a valve and switch.
Run the main tank down to reserve, switch to the belly tank and run the pump then when the bike starts to sputter switch off the belly and switch on the reserve.
This is the setup used by TourTank for their Aux tanks but they are normally gravity fed.  Adding a pump shouldnt be an issue and it would answer your issue with running the pump longer than needed.

[MarkT]

OK I figured it out.  The plumbing connections with electrical mods that is.  Roger at R&M tells me the fuel pump parameters - 2.0-3.5psi - the upper limit is controlled by the strength of the internal spring.  Use a weaker spring to lower the peak pressure.  He says unmodified, the pump tests consistently at 3.0 lbs. I might weaken it anyway - using a Honeywell 1.1-3.0 pressure sw, don't want the sw to shut off when the pump is running right at the threshold of the upper sw limit.

• The main filler hose attached to the bung:  connect per R&M's plan but add inline an Ehcotech NC fuel solenoid with internal 5/8" port for high flow.  This solenoid is activated only while refueling, so power available with engine off.
• Install a T fitting in the OEM fuel line and connect the pump outlet from the belly tank to the supplied fuel filter then to the T fitting.  
• Modify the petcock per R&M's plan and plug the vacuum line from runner 6 per their plan.  
• Run the belly tank vent up under the OEM tank and put a fuel filter on it to keep spiders out; secure with wire ties in the fuel rail area.  
• Install a Dan-Marc downstream of the above T-fitting (usual place for a Dan-Marc). Wire the Dan-Marc with a latch relay, push button, and LED per http://www.horseapple.com/Valkyrie/Tech_Tips/Fuel_Shutoff/fuel_shutoff.html
  
• Install a toggle sw, and LED (reminder to shut off) to activate the filler solenoid. Or maybe a latch relay shut off automatically when ignition on. (I know me, might forget even with reminder)
• Install a latch relay, low pressure sw, push button, and LED to activate the fuel pump when the OEM tank runs out (in lieu of selecting reserve on the main).  

In operation, I might find selecting the fill from the belly tank is too slow to replace the reserve fn at the petcock.  So might have to select reserve, then activate the transfer - then shut the reserve off again.

I think that covers it.  Seems like a lot but I like this kind of project and it will be awesome in operation.

If my bike is ever delivered by HAULBIKES.

DON'T USE HAULBIKES.

[MarkT]

I seriously don't think a pressure switch is going to answer your problem.
mainly because there isn't going to be any pressure just from pumping fuel from one tank to another.
now what might work if you wanna go this route is a Honda oil sensing switch.
if you look at all small Honda engines for mowers, saws, concrete and mortor mixers.
you'll see a switch mounted low in the crank case. the way this switch works is. the ground runs threw this switch. if the engine oil gets low enough that the switch is no longer submerged in oil it goes open and removes the ground from the ignition. in most cases the way they have that switch in there you have to split the case to replace it. but you may be able to find one that screws in. if you mount it say within 1 inch from the bottom of the tank then run the ground threw this switch to the ground on the relay it will remove the ground from the relay when the gas drops below the switch. and cuts the relay out.

Looked at oil level switches on ebay.  The Honda ones look difficult to adapt.  But there are a lot of other ones, particularly for Kohler and metric bikes that would be easy to install. Assuming it doesn't matter if it's submerged in gas rather than oil.  If the pressure sw doesn't work I'll head this way.  Thx.

[3W-lonerider]

it shouldn't matter whether it's gas or oil.
because you'll be running the ground from that switch and not positive.
I think those switches are designed to see fluid. if no fluid then they go open circuit.

[Robert]

I have never had a problem with the tank and have replaced the pump 1 time in 50,000 miles. Sounds like a lot of work. The Facet pumps are really simple just a slide and a couple of valves. They do make different styles of pumps if you are worried.

[MarkT]

I'm not worried and my pump won't fail since it's not running all the time.  And I don't have to do a special hose-switching repair on the side of the road to return to OEM fueling if the pump does fail - like you will if yours fails again - because I am already OEM fueling with gravity, and protected from hydrolock with a Dan-Marc. This plan is the factory fueling setup that does not DEPEND on a fuel pump, with a large reserve - in addition to the OEM reserve.  Better design in my book.

That is, if my bike is EVER DELIVERED BY HAULBIKES.

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