Should I plan to put a ground wire on the fuel gauge senders?

Hi Folks,

Has anyone ever had a problem with fuel guage accuracy that turned out to be a bad ground?

I'm currently picking away at building the tanks for an RV-7 with float type fuel gauges.

My plan is to get some stainless steel Allen head screws instead of the Philips ones that Vans provides. ( There should be less chance of striping them out if they ever need to be removed.) These will hold the inspection plate on where the fuel pick-up and fuel guage float Are located. While I am at it, I would consider getting some type of stud arrangement so that I can put a ring terminal on it and send a ground wire to something that is well grounded.

Is this something that would help the accuracy of my fuel gauges...or is it just an added weight and waste of time to do?


Cheers,

Steve Wolfe

I used SS allen head screws to install my fuel senders and the cover plates.
I did not add additional ground wires and the gauges have been working perfectly for over 20 years.

Insurance

I did exactly as you said - for insurance. From 1985 until now - 2 airplanes, no glitches, and have done it again on the -3B I am currently building. You buy insurance hoping not to have to use it - but if needed, it's there.

HFS

Look at it this way, it's cheap insurance that you won't have any issues. Is it absolutely needed? No. Will it hurt anything? No.

It's interesting to note that now Van's has changed the plans on the RV-12 and ADDED a ground wire to the fuel sender. I just think it's easy and eliminates a possible sender issue in the future. I've done this on all my previous builds, even the Cobra!

f1rocket said:

It's interesting to note that now Van's has changed the plans on the RV-12 and ADDED a ground wire to the fuel sender.

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This is not correct.

A change was made to add a star lock washer under one sender screw, and one access cover screw to help assure good ground continuity through to the body of the tank.

eh_v8_tor said:

Hi Folks,

Has anyone ever had a problem with fuel guage accuracy that turned out to be a bad ground?

Cheers,

Steve Wolfe

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Yes, and not only fuel gauges. Do a search and you will find some great examples.

rvbuilder2002 said:

This is not correct.

A change was made to add a star lock washer under one sender screw, and one access cover screw to help assure good ground continuity through to the body of the tank.

Click to expand...

I stand corrected. I could of swore that a wire was added, maybe the wire is optional in the instructions? Oh well, I'll have to go back and read that more carefully. In any event, I will be adding a grounding wire from the sender to the airframe, after the 5 hours are flown off of course.

where to attach the ground wire?

I added the wire, but wonder where to attach it on the airframe side? I don't really want to bring it inside. How about a screw tapped into the big fuel tank angle brackets?

I just finished putting in the float sender and closing up my tanks.

I added a ground wire with a star washer, used hex head screws, and used wicking Loctite on my rivets.

These were quick build tanks so I did not build them. I looked inside the tanks as best I could with my borescope and it appears that they are sealed ok.

I have not tested them yet, that is the next step.

I've installed dedicated ground wires run all the way from the fuel senders to a master ground bus in all the RVs I've wired up.

However, my old Cherokee did just fine without them for nearly 50 years, and its fuel tank senders and guages and wiring are still working fine to this day.

Are they really necessary? No.
Do they make you feel better about the wiring job? Certainly

gound loops

Im with Neal on this, everthing ground to a common ground buss. It only costs a few extra ounces of weight, may prevent ground loops and/ or radio noise.

I wish I had done mine like this when building my tanks. I often get a fuel low warning from skyview when the grounding is not good. Then it fixes itself, I should run an extra wire to fix this fault..... one day....

Taildrgr said:

I just finished putting in the float sender and closing up my tanks.

I added a ground wire with a star washer, used hex head screws, and used wicking Loctite on my rivets.

These were quick build tanks so I did not build them. I looked inside the tanks as best I could with my borescope and it appears that they are sealed ok.

I have not tested them yet, that is the next step.

Click to expand...

I used isolated ground wires back to the Engine Pod in my RV-6A; the common ground was too noisy for the sensitive BMA device to read. The biggest problem was isolating the senders from common ground; I ended up using nylon shoulder washers under the screws. When I eventually change from the BMA system, I will keep the isolated grounds.