Does your dash give any error code, or can you maybe do a read-out on the ECU? The fuel light should work no matter what.

 

I don't see any error codes on the dash. I wonder if an ECU reset would help? I am going to let it run down a bit to see if it comes on after a full tank of fresh (non lawnmower) gas.

I am going to add some extra flashers up front, so the ECU will be without power for long enough to reset itself.

If not, I will just add some juice every 75 or so.

 

Just fill up every 75 miles.

 

I would just keep riding around blagging fuel?

Gas aint cheap.

 

99 oct. gas here in the UK is $8.56 a US gallon...

 

you people should revolt, seriously. if gas was $8/ gallon in the US I guarantee there would be a revolution.

 

I always attempt to know where the stations are on my route and start to panic if I haven't seen a station 75 miles into the ride. I think panhandling folks for fuel seems to be working. Pick up something to sell when riding, sounds as if it could become quite profitable for you. Seems you've got the knack for it. You must be the clean cut biker type?

 

I think I missed my calling. All these years I've been paying for gas. I guess there is a bit of a socialist in me after all! Now all we need is the gubment to force these suckers into keeping high test in their lawnmower cans.

 

The problem is the low fuel sensor on the pump is faulty. Mine has been like that for over a year. I fill up at 100 miles.. I ran out of gas at 125.8 the only time I ran out..

 

have you inquired about what it would entail to repair the faulty sensor?

1. small tank on this bike
2. relatively thirsty V-twin
3. no fuel gauge
4. the bike is too fun to ride economically!

All these factor in to make the light a necessity.

 

I don't know that I could make 100 miles unless I slowed down drastically. 125 is definitely out of the question

 

Ca Cycleworks 6.4 Gallon Hypermotard Fuel Tank | ca-cycleworks.com


Yup.

 

Ca Cycleworks 6.4 Gallon Hypermotard Fuel Tank | ca-cycleworks.com

Yup.

This was going to be my suggestion.

PhilB

 

the fuel sensor is just a temperature probe. it should work now when the temp changes as the fuel runs out. my probe went bad and when it did the cpu flashed the light and didn't read countdown mileage. i believe if you don't have the bike running or at least on when the probe gets uncovered it wont alert you your low on fuel. so if you put it away with low fuel and disconnected the bat or the fuel evaporated enough to be low when you restarted for this year it could never see the change in temps required for a low fuel light.

 

Wierd - same thing happened to me. Last year the fuel light had worked perfectly. I got my bike ( 2008 ) out for the first run this year ( I'm in MI ). Tank was full over winter. I had set my trip to zero at fuel fill. Whilst I was out riding, I glanced at the trip and saw mileage at 125 - and suspected something wasn't right. No more than 100 yds further along, during a long LH sweeper the bike died. Had to walk to the nearest house to borrow some tractor gas. The fuel light still wasn't on.
Odd that it happened first ride after winter - just like the O.P.

 

OK - Done some research. Most likely the thermistor or its heater has gone bad.
Can anyone help with diagniostics on the thermistor ? I've looked but can't find any info.
What are the wire colors for the heater coil and the thermistor path ?
What should the coil resistance be ?
Assuming it has gone bad, has anyone tried fixing it ( replacing the discreet electrical components ) Vs parting with $151 for a new Ducati item ?
I know I can just forget the light and use the trip - but broken things bug me.

 

Update : Learned that thermistor is self heating ( no coil ! ) - and is the blue and white wires going into the tank. Measured resistance in 3.8 KOhm, so I don't have a broken circuit, and it does decrease resistance once energized with low fuel , ( ran the bike, stopped and quickly measure resistance ) but the resistance only drops to 1.5KOhm - maybe not enough to trigger the light.

 

I contacted indy ducati and they said a new thermistor would be 56.99. Btw. Those quick connects that connect the fuel lines to the fuel pump.. 15.99 each, so don't break them.

 

nitsuj, Thanks for looking - that's probably the monster etc. thermistor, but I'll look into it. They are just a small can. The hyper has an extension arm brazed to it as it is positioned differently in the tank - between the pump and the filter.
Today I pulled the sensor and removed the thermistor from the can. It tests at 3.8 KOhm at room temp and 1.5KOhm at 80c. Still think this is too high. The thermistor is a tiny part - about 3mm long, looking like a resistor but with a machined profile. I now need to find out about this part.

[/url] [/IMG]

 

Update :
1) Part numbers : There are two versions of the parts catalogue out there for the 2008 Hyper 1100, one dated 03-07 and one dated 08-08. The earlier one, as is used by DucatiOmaha.com and others, shows the part 55240481A which is the part without the "leg" for about $55. This will not fit directly. Ducatimcparts and others use the later catalogue and show part 55242001A for $151 which I believe is the correct part, but I haven't seen a good image of it.
2) Testing. Did some more scientific trials. The thermistor from my sensor when heated in fluid shows 650 Ohms at 100C, but it will not achieve that temp from its own heating in air. By playing with a potentiometer, I now know the fuel light needs a drop to about 150 Ohms to light, so it's clear why the light isn't coming on. I've also collected data to help me spec the thermistor I need. Now I just need $2 to buy one and fit it in.

 

Sorry for not updating sooner - once the bike was fixed I had better things to do !!
I did finalize the spec for a replacement thermistor, procured some and tested that they would work. However, as part of my study I needed to measure an OEM part to check my maths, and so I bought a low mileage used pump assembly ( with sensor ) off Ebay. Having finished the study I had the option to use my new device, or just put in the used one I'd bought, and opted to put in the used part. ( At that time I learned of folks having issues with the tank captive nuts coming loose and so didn't want to risk having to take it all apart again if my design had issues.)
So, my design is done, but the output not proven. When I get time I'll post what I had come up with.

 

Very interesting. Thanks for the update. Subscribed.

 

So the end result was a full replacement fuel pump? ebay has them for about $85. Looks like I'll be just using the trip meter from here on out. till x-mas.

 

Sorry for the delay - been busy !!!
First how it works : The thermistor is a device which changes resistance with temperature, with resistance dropping as temperature increases. As it is a resistor, it generates heat, which in turn reduces its resistance, generating more heat etc etc... When the thermistor is inside the fuel, the heat dissipation to the fluid is high enough that it exceeds the heat being generated by the thermistor and hence its temperature is stabilized at a certain level. However, when the fuel is low, and the thermistor is in air, the heat dissipation rate decreases, such that the thermistor starts to increase temperature. The fuel light works by putting the thermistor is series with a set resistance in order to deliver a designed current to the dash when the thermistor resistance ( as dictated by its temperature) rises above a defined value.
Measurements : Using a potentiometer in place of the thermistor it was possible to deduce that the light will come on when the thermistor resistance is below 160 ohms. By measuring the voltage drop over the potentiometer at various values it was possible to deduce that on the bike the thermistor is in series with a resistor of 116 ohms. What has happened to my stock sensor was that it was still generally working, but did not drop resistance far enough, hence the light did not come on.
Challenge : need to find thermistor which will provide the correct characteristics : resistance in fuel > 160 ohms, resistance in air < 160 ohms, but beyond this must have high resistance in fuel to avoid big constant current draw, and must be such that it doesn't go unstable ( heat up excessively) when exposed to air. Thermistors are defined by their B value, but generally also share their dissipation constant in air, and the current they will accept. Using this it was possible to build a system model, calculating resistance and hence heat generation, as well as the heat dissipation rate when in or out of the fuel. Of course, it is also somewhat important to make sure that the thermistor in air does not exceed the fuel auto-ignite temp, or the max temp permitted by the thermistor.
Result : using published properties, and knowing something of the application, I was able to select the Honeywell 135-202FAG-J01 with B value 3468K and dissipation in air of 2.5mW/degC. The nice part of this thermistor is that it is glass encased, and hence not affected by the fuel as I suspect the stock ones are. Cost was a whopping $1.47 a piece.
Testing : Bench testing was completed with 12v and a series resistor of 116 ohms to confirm that the thermistor selected responds as expected, and then I fitted it to the bike ( but not in the tank) and confirmed function by testing in and out of fluid. The fuel light worked as expected. As the worst case for the thermistor is when it is dry, I ran the thermistor in air for 24 hours constantly, and all seemed fine. However, this is as far as I got and never fitted the thermistor to the bike. I will when my light fails next time. To fit it, I'll need to dismantle the stock sensor, and fit the new thermistor in place of the old one.
BTW - note that the thermistor is mounted inside a can which has only small holes in it, such that the thermistor response is slowed and the light doesn't go on/ constantly when the fuel level is near the switch level.

So that's the status - the design is done, but not yet tested. Try it at your own risk !




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Awesome data thanks. Saving me a ton of time.

 

awesome. I seem to have hit the final straw at least twice this year. The first time was a trip through a nice mountain road running out of fuel twice while looking for a single gas station. This made my spring day off, day trip a PITA. Second was running out of gas on my way home from work on the first freezing day of the year, 1 mile from home at 3:30 am. I had to push my bike for 3/4 mile in riding boots.

I am constantly cautious of my fuel level and I still ran out of gas at least three times this year.

 

If the whole fuel pump only cost $85 then why would you just buy the thermister for $151 which is included in the fuel pump?

 

An eBay pump is $100 with no guarantee. From Ducati the pump is propbably a grand.

 

Thanks to GT6Racer the 82 cent repair is working great so
far. Having a lightweight flywheel, stacks, Termi 2 into 1
and a heavy right hand and no low fuel light is a bad
thing. My wife has has to bring me a gas can a few times
now. The Thermistor is a 163.00 part from Ducati and
they have tried to make it a non repairable part but
with a little work it can be repaired.

The Thermistor is in a small metal can attached to a
metal post strapped to the fuel pump. It is attached
to one wire at the bottom of the can held apart from
the can by a fiber disc. The 2nd attachment is to the
metal can by a small hole in the top of the can. The
bottom wire attaches to a plastic plug the 2nd wire
attaches to the mounting screw for the metal can and
then to the same plug completing the circuit.

You have to pry out the fiber disc at the bottom of the
can the edges of the can are bent over locking it in.
The solder joint at the top of the can needs to be
released to remove the other end of the Thermistor.

The green wire at the bottom of the can runs into
a brass tube that was soldered onto the wire then
crimped onto the end of the Thermistor. This broke
when I tried to undo the crimp so I just soldered
the wire onto the Thermistor. The small brass tube
is still in the fiber disc but broke just after it exits
the fiber disc that is were it was crimped.

The attached pictures show the original Thermistor,
the new Thermistor the broken piece of the brass
tube. Also they show the Thermistor can and mount
and the plastic plug. And my now working fuel light.

 

Great info, @hypermo. It would've come in handy for me earlier when I was considering fixing my fuel warning light, but now I've taken to riding with a 12L fuel bladder in the tailback if I'm needing to stretch between service stations.

That said, I'm hoping to (finally) get around to stacks at some point so I might revisit the thermistor then.

 

I am looking into a fuel bladder or a fuel bottle to carry in my kreiga tail pack
as well. I was thinking of removing the stacks and going with the Ca Cycle
Works larger tank, but They are to much fun the sound and the way they wake
up the bike are addicting. With the lightweight flywheel and the stacks the
bike spins up much faster and low end torque seems the same.

Its so nice to have the light working again and but its no cure for running
out of gas if your far from a gas station. But its nice to not have to guess
when it is going to happen the light comes on find gas now.

The Thermistor was 82 cents the shipping was around $5 so I bought
4 of them. I just could not justify paying $163 for a 82 cent part in a
metal can with 2 wires and a plug from Ducati. And if you buy a used
fuel pump off E-bay you have no idea if the Thermistor is good or how
long it will last. And like the other poster it just bugs me when something
on the bike is broken.

Again thanks to GT6Racer for doing all the work and testing he is that one
that made this fix possible.