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Dynon fuel quantity

dmcewen

Member
During construction I calibrated the fuel quantity gauge according to the plans. During phase one flight testing on a high angle of attack power on turning stall I think the float in the tank got stuck somehow. For the next 15 hrs. the quantity on the Dynon read 14 gallons, then yesterday during a flight it droped suddenly to 0. After the flight I disconnected the lead to the sender and measured the resistance on the float (246 ohms) then added 7 gal of fuel, resistance stayed the same. I am thinking the float may have failed in the tank someway. Any thoughts/ideas?
Dick
 
Hey Dick - -

Be sure you have a good ground. I did so good dipping the front plate screws, I did not have a ground. Had to run a separate wire to the sender itself. With your meter, check from the terminal to the aircraft frame.

John Bender
 
Be sure you have a good ground. I did so good dipping the front plate screws, I did not have a ground. Had to run a separate wire to the sender itself. With your meter, check from the terminal to the aircraft frame.

John Bender

Same here - ground wire fixed the problem. I suggested adding this as standard but Van's didn't think it was necessary.
 
Same here - ground wire fixed the problem. I suggested adding this as standard but Van's didn't think it was necessary.

A different (simpler) change was made.... Added an internal tooth lock washer to one each of the sender flange and cover plate screws, to make a good ground connection through a film of tank sealant.
 
Page 37-04 no internal tooth lock washers?

A different (simpler) change was made.... Added an internal tooth lock washer to one each of the sender flange and cover plate screws, to make a good ground connection through a film of tank sealant.

Good information, I plan to do this with the fuel tank mod, but I don't see them on the latest revision of the fuel tank plans.

How about including them in the fuel tank mod kit, or at least spec them out so we can buy them :p.

Tony
 
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Good information, I plan to do this with the fuel tank mod, but I don't seem them on the latest revision of the fuel tank plans.

How about including them in the fuel tank mod kit, or at least spec them out so we can buy them :p.

Tony

Hmmmm... I was pretty sure a revision had been implemented for this. I will try and remember to check when I am no longer "on vacation".
 
Lock washer didn?t do it for me. There seemed to be no good ground to the fuse after our tank overhaul and SB work. I had to add a ground wire.
 
Stewart-Warner?

I assume we're talking about the Stewart-Warner senders, correct?

Originally when I built my plane I used Vans round gauges. The fuel gauges generally worked.

I recently installed a JPI EDM 740 engine monitor. The engine monitor is more finicky when it comes to the resistance coming from the senders. I am having problems with the left side. When I measured the resistance I found that I don't have a good ground.

Are you suggesting removing one of the fuel sender mounting screws and putting a lock washer under it. It seems that would introduce a fuel leak at that screw.

I don't see any other way to mount the ground wire to the sender. I've considered glueing the ground wire to a bare spot on the sender mounting plate using electrically conductive epoxy.

Next time, I would modify the mounting plate to include a grounding screw.

Michael-
 
Electrically conductive epoxy might conduct static electricity. I doubt that it would conduct low voltage signals.
 
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