Reliable Fuel Readings - better fuel sender design?

[hornie]

Our fuel gauge reads full for about 3 miles, half for antoher 3 and them empty for the rest of each tank. Ultima assure us that there is nothing wrong with the gauge. So apparently the problem is to do with the shape of the tank and the fuel sender simply cannot read the actual level because the tank is so wide at the bottom.

This proves a dilemma for Simon and me, as we both drive the car. Particularly when he forgets how many miles he's done on which tank I have run out of fuel twice!!
How do we know how much fuel each tank has used and when it really is empty without having to fill up every single journey? Or (mortification) having to write the mileage down. (nooooo you just can't do that with this car!!!!)

There are ways we can deal with it practically, but I still cannot believe that there is not some way of finding a fuel sender that actually reads the tank properly.

Are we the only people with this problem, has anyone else done any research on this issue?

[CanAm Dave]

Hi Dawn

I'm in the process of changing my 52mm gauges at the moment. My new ones are made by SPA and they are bringing out new version of their fuel gauge in a month or so which will solve the problem with the shape of the Ultima tanks. It will still use the standard VDO fuel sender. The way it will work is that you be able to map the shape of the tank by adding fuel a couple of litres at a time and then map that position in the gauges electronics. The gauge has a remote button switch which allows you to scroll though the gauges menu and functions. The same button is the one used for mapping the shape of the tank. The standard gauge and sender will never work well. Mine is the same as yours. I think you will struggle to find a non-linear sender unit that works with are tanks. Unless anyone knows otherwise!

Regards Dave

Edited by CanAm Dave on Wednesday 19th July 13:07

[hornie]

You are a star! Dave. Now i can say "I told you so" to Simon. He's gonner hate that.
Do they have a website with details?

Edited by hornie on Wednesday 19th July 13:30

[stig]

That's the nice thing about the stack, you calibrate it as you fill the tank. Very accurate

[usagtrman]

Hi Dawn:

Many General Aviaition airplane fuel guages are the same as what you're describing. The solution for nervous pilots is to install a computerized fuel flow/totalizer system. These systems have a transducer mounted in the fuel line which "reads" all the fuel that goes through it. The panel mounted computer knows the starting "full fuel" level and then deducts everything that the transducer sees running through it...hence providing a constant "fuel remaining' number. In these applications the units also display your fuel flow in gallons/litres or pounds and when interfaced to nav systems provide range calculations and more. I don't see why one of these wouldn't work in a car. Certified systems are fairly expensive but there's some non certified stuff that should work as well. I get used systems periodically which would be even cheaper. It would be a fairly complicated way to solve the problem but if you've got to know.....this would do it. Just take a look around Simons RC stuff when he's not at home.....you may already have one!! For me......I just go to the gas station all the time. Good luck!

Brad Z

[hornie]

usagtrman said:

Just take a look around Simons RC stuff when he's not at home.....you may already have one!!

never thought of that - will do Thanks Brad

[CanAm Dave]

Hi Dawn

Its the dual gauges that I have you will find them at www.spa-uk.co.uk

The new fuel gauge will not be out for a month or so. Don't order the one they are selling at the moment.

I'll send you a mail when the new ones are in stock.

Regards Dave

[hornie]

Thanking you!

[davefiddes]

Some ECUs can produce a linear reading. Was planning on doing that at some point on my car. Allows me to keep the original analogue gauge which I like.