What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

SO tired of in-op fuel gauges

pa38112

Well Known Member
On my 6 the Vans fuel gauges are in-op about 85% of the time. I have replaced both senders and both gauges. I have cleaned all conections, and re-cripmed the wires. Sometimes they start working mi-flight, sometimes one works and not the other. I don't remember replacing the ground wires tot he gauges, but I am sure I would have. Any other suggestions?
 
IMHO, it's the gauges themselves, they seem to just go wonky at times. My -8 has the Vans analog fuel gauges; over 16 years and 1900+ hours I've replaced the right gauge once already, and now the newer replacement is acting weird. Often on engine start with bus voltage drop, it'll drop to zero, so I then recycle master switch after start to bring it back. Sometimes it'll do a random sweep and maybe stick, so a knuckle tap on the panel frees it up. My left gauge has been solid until this past summer when it just dropped to zero in flight. Knuckle tap didn't help. Next shutdown/start cycle fixed it. Weird.

These gauges aren't produced any more, but, I have a pair of new old stock Vans gauges on the shelf to go in as replacements and one of these days I'll swap them out... if they don't last another 15 years I'll probably replace them with a new pair of Mitchell gauges.
 
Here is the gauge I've been using with the stock Vans senders since the RV-6 first flew in 1999:

https://iflyei.com/product/fl-2-dual-fuel-level


The gauge is very accurate after the first 3-4 gallons are used (this is a function of dihedral in the wings) and blinks to let you know when fuel imbalance has reached a certain point.

FL-2_web-400x395.png
 
same config as Sam points out to above… the most precise fuel indics I’ve had on any airplane :)
 
By far a fuel flow meter is the most accurate way to determine how much fuel has flowed through to the engine. Sadly, it can't tell you when the tank has sprung a leak.

I have a Vans sender in each tank and a Red Cube after the pump, all three are connected to my MGL fuel gauge. The level readings are good once the first 1/4 tank is used. The totalizer has been 100% accurate from full to empty, as evidenced by fill-ups where the number on the pump matches the number in the gauge to within 1L.

Were it legal to do so, i'd put a red cube on the flow out of each tank, and get rid of the senders... Subtracting fuel used from fuel total is much more accurate.
 
My -6 still has the original resistance senders from the late 90's. Every few years the fuel level readouts on the G3X get wonky and swing between empty and the proper level, which might be from lead deposits on the resistance wire. When that happens, I use BG 44K fuel system cleaner (1 can per tank) which clears it up by the time the tank is empty. Learned about 44K here on VAF many years ago.

https://www.bgprod.com/catalog/gasoline-fuel-system/bg-platinum-44k-fuel-system-cleaner/
 
This is what I had in my -6 and am installing in my current project. Love this gauge!

I think I have an EI dual fuel gauge as pictured that is sitting on the shelf. Make an offer if interested.

Bevan
 
On my 6 the Vans fuel gauges are in-op about 85% of the time. I have replaced both senders and both gauges. I have cleaned all conections, and re-cripmed the wires. Sometimes they start working mi-flight, sometimes one works and not the other. I don't remember replacing the ground wires tot he gauges, but I am sure I would have. Any other suggestions?

If it makes you feel any better, I have the exact same issue with the fuel level indicators on my G3X. So I'm not sure it's the analog gauges. I'm guessing the senders are the culprit, but they never seem to work right.

--Ron
 
By far a fuel flow meter is the most accurate way to determine how much fuel has flowed through to the engine. Sadly, it can't tell you when the tank has sprung a leak.

I have a Vans sender in each tank and a Red Cube after the pump, all three are connected to my MGL fuel gauge. The level readings are good once the first 1/4 tank is used. The totalizer has been 100% accurate from full to empty, as evidenced by fill-ups where the number on the pump matches the number in the gauge to within 1L.

Were it legal to do so, i'd put a red cube on the flow out of each tank, and get rid of the senders... Subtracting fuel used from fuel total is much more accurate.

I agree 100% with the use of a fuel flow meter and totalizer as used on my D-180 for true accuracy. I dip my tanks prior to every flight when not full and am always amazed that they are within one gallon of each other. Also back it up with 30 min timing based on a given FF. My fuel gages are pretty worthless until 6 gallons remaining in each tank.
 
With the exception of the whiskey compass which is equally as useless, the fuel gauges in the RV-6 I've been flying for the last 26 years are absolutely a waste of panel real estate. I can put my hand on my heart and say that in all this time I have only once referred to them and that was out of curiosity, to see whether they worked. They do, but only when the fuel quantity drops below 50% do they start to move. Today, I couldn't tell you if they were still working or not. We just never look at them let alone rely on them.

Our practice is to dip the tanks before getting in and then making sure the fuel quantity is reflected correctly on the E.I Inc Fuel Flow Gauge prior to start. The E.I Inc system works great and the rest comes down to fuel management between tanks. I've never been in the habit of relying on fuel guages on any G.A. aircraft. Knowing the engines typical fuel flow and erring on the high side has meant I am yet to run out of fuel.

Touch wood.

Buy a good Fuel Flow system and enjoy the benefits it brings.
 
For over 16 years, my Van's fuel gages have been very accurate. I have dedicated ground lines for each gage. I stick my tanks before every flight. The stick is marked per gallon and has been proven to be less than 1/2 of a gallon (5 minutes of flight) off at fill up.
 
For over 16 years, my Van's fuel gages have been very accurate.
Same; gauge wonkiness aside, most of the time my Vans gauges are very accurate.

But, this discussion appears to have set off the gremlins again; when I flew yesterday the left fuel gauge played dead during engine start. Recycling the master switch fixed it. First time my left gauge has done that… looks like one day soon I’ll be dumpster diving behind my panel to swap out both gauges.
 
Odd for me to say, but my 20 year old Van's mechanical gauges are very accurate, if they read 10 gallons remaining in level flight, and I land and top off they come in +/- 1 gallon. I have a JPI EDM350 and have contemplated moving the fuel levels over to it, but the last thing I want is to go from accurate to inaccurate, so I've decided to leave them as is for now.
 
Is it legal to fly with an in op fuel gauge, asking for a friend?

In an Experimental? Sure - unless the Operating Limits say otherwise. Generally speaking, E-AB aircraft require no instrumentation at all to be legal to fly….

I would, however placard something that doesn’t work as “inoperative”, just because that rule can get fuzzy in the E-AB world with many FAA inspectors….
 
Last edited:
In an Experimental? Sure - unless the Operating Limits say otherwise. Generally speaking, E-AB aircraft require no instrumentation at al to be legal to fly….

Just for clarification.....the above statement is true for day VFR ops. Most Operating Limitations state night and IFR require compliance with FAR 91.205....pretty sure that is what Ironflight was saying. :)
 
Same; gauge wonkiness aside, most of the time my Vans gauges are very accurate.

But, this discussion appears to have set off the gremlins again; when I flew yesterday the left fuel gauge played dead during engine start. Recycling the master switch fixed it. First time my left gauge has done that… looks like one day soon I’ll be dumpster diving behind my panel to swap out both gauges.

You may just have a dirty connection. The surge of the master makes a temporary connection.... like a bad starter solenoid on a car that will start after several key movements.

These gauges require clean connections. Clean each one and coat with De-Ox.
 
I built an early -7A that first flew in ‘03 with vans gauges. 75% of the time one or both of the stock Van’s gauges would die to zero during start and not come back alive. Cycling the master always resurrected them.
Before I got out of phase 1 I put a fuel gauge power switch in the panel. After start I flipped it on and the gauges always came to life and were fairly accurate all of the 15 years I owned the plane.
 
I like to have a mechanical gauge that works, I find it just takes away one of those nagging doubts. I have had,
No reliable gauges - I didn't like the uncertainty
Automotive gauges and senders - OK initially but gave up
Van's gauges & senders - accurate, especially when it mattered, and reliable most of the time
EFIS gauges with Van's senders - too complicated to set up and trying to be too clever
UMA gauges (below) with Van's senders - only 18 months in seem to be doing OK.
 

Attachments

  • Fuel gauge.jpg
    Fuel gauge.jpg
    79.1 KB · Views: 54
My Vans fuel gauges never worked and I tracked the problem to engine start. During the start the battery voltage dropped to below 7 volts and when this happened (often) the fuel gauges quit working and would not restart until a power down. I proved this by removing the fuel gauzes and replicating the problem on the bench with a viable power supply. My conclusion is that it’s a design flaw but a silly workaround would have been to power the gauges through a NC push button switch. When the problem happens after startup, push the button and the gauges would reset and work fine. I choose to buy another brand of fuel gauge instead.
 
Back
Top