fuel gauges

Mike Ice · #1 03-10-2009, 10:10 AM

I have Van's resistance float type arm fuel senders in my RV-9 tanks and I am wondering how hard it would be to change them out to the other type type of sender.

Has anyone done this mod? What does it involve?

Mike Ice

yakdriver · #2 03-10-2009, 10:52 AM

What kind of gauges are you hooking them too? Mine are hooked to my Dynon 120 and they are very accurate. Don

Mike Ice · #3 03-10-2009, 11:08 AM

I just have the standard Van's gages right now but they are not working properly. I think I installed the floats wrong or something like that. The gages read empty when the tanks are full of fuel and never go up to half full even when there is less fuel than that.

I thought since I have to do some work on them anyway if the capcitive senders are better and the job isn't too tough then I might upgrade.

Mike Ice

Jamie · #4 03-10-2009, 11:28 AM

To change to a capacitance type fuel senders would be a huge undertaking, including removing the tank, drilling out the rear baffle, etc.

A faster fix would be to just fix the sender units, which is exactly what I would do. Or, I would get some better fuel gauges, such as electronics international, etc which can be calibrated to virtually any ohm range. Be aware that the float type senders will only show a change over the last 15 gallons in the tanks since any larger quantity of fuel will have the float at the top of the tank due to the dihedral of the wing.

az_gila · #5 03-10-2009, 12:17 PM

Quote:

Originally Posted by Mike Ice

I just have the standard Van's gages right now but they are not working properly. I think I installed the floats wrong or something like that. The gages read empty when the tanks are full of fuel and never go up to half full even when there is less fuel than that.

I thought since I have to do some work on them anyway if the capcitive senders are better and the job isn't too tough then I might upgrade.

Mike Ice

...than a switch (upgrade) to a more modern digital gauge might just do the trick.

The test to perform is to measure the resistance of the sender with 0, 1/4, 1/2, 3/4, full tanks.

If the resistance varies and the numbers are in a reasonable range, like zero to 300 ohms, then a gauge upgrade might just do the trick.

And if that works, I even have one of these to do the trick....

http://www.aircraftspruce.com/catalo...fl100level.php

Open to offers - it's the FL-110 R version.

asav8tor · #6 03-10-2009, 12:17 PM

2nd vote for electronics international

When you program their gauge you can specify which way the gauge reads empty/full so no need to mess with the probes. Also you calibrate the gauge by starting empty, add 2 gallons press the button, add 2 gallons, press, etc. In my case the probes are installed in different locations to make room for the flop tube. With this feature the gauge is very accurate. I had the vans gauges before and I really didn't know how much fuel I had.

Norman CYYJ · #7 03-10-2009, 12:59 PM

I suspect your senders are upside down and I think the only way to do that is to mix up the left and right sides, because of the hole spacing won't allow them to be put in any other way.

Mike Ice · #8 03-10-2009, 01:15 PM

Thanks to all that have replied.

I guess I need to take the units out of the wings and check them to see if I put the right in the left. Could have happened.

If I understand correctly the Aerospace logic instrument would even compensate for that mix up. Is that right?

So, a multi meter across the wires with the tanks at the prescibed fullness would give me the indicted ohms. Pretty smart idea. I was thinking I would have to remove the senders to test for ohms.

I get the picture, changing to capacitance isn't a good idea. Thanks.

Mike Ice

asav8tor · #9 03-10-2009, 01:26 PM

Quote:

Originally Posted by Mike Ice

I guess I need to take the units out of the wings and check them to see if I put the right in the left. Could have happened.

If I understand correctly the Aerospace logic instrument would even compensate for that mix up. Is that right?

No you don't need to take them out.

The EI unit can read them either way as that is part of the gauge programming. The Aerospace logic unit MIGHT have that feature also.

I have the EI fuel gauge and the Aerospace logic volt/amp gauge. The Aerospace gauge came with certified paperwork and I think all their gauges are such; Not that it matters for exp. If the Aerospace logic gauge has the reversing feature and you get a good deal on it that might be the way to go. If I had to pay full price I would go with the EI.

az_gila · #10 03-10-2009, 01:41 PM

Thanks to all that have replied.

I guess I need to take the units out of the wings and check them to see if I put the right in the left. Could have happened.

No - measure the resistance with the senders in place.

If I understand correctly the Aerospace logic instrument would even compensate for that mix up. Is that right?

Correct - as long as the senders are creating a varying resistance with fuel level.

So, a multi meter across the wires with the tanks at the prescibed fullness would give me the indicted ohms. Pretty smart idea. I was thinking I would have to remove the senders to test for ohms.

Yes - and make sure that you have a zero ohm connection from the "plate" of the sender to airframe ground.

I get the picture, changing to capacitance isn't a good idea. Thanks.

Yes... way too much work - would essentialy need a tank rebuild...

Mike Ice