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Fuel Quantity Gauge failed
Posted: Sun Jan 16, 2022 6:03 pm
by yl472401
After a few weeks of leaving the airplane in the open with canopy cover, I attempted to do some afternoon refreshment of the pilot skill yesterday afternoon and came across this problem which eventually lead to my abort the plan.
The right side fuel quantity gauge has failed and got x'd out ( see picture).
I tried a few times with reboot the computer without success and eventually decided to wait for another day since it's getting dark outside.
I have a couple of questions regarding this issue.
1. Could this because of the low temperature
2. Will it be resolved with the temperature gets warmer?
3. What's the cost of have it replaced?
Thanks in advance.
![Image]()
Re: Fuel Quantity Gauge failed
Posted: Sun Jan 16, 2022 6:16 pm
by Steve
Bryan:
1. Possibly
2. Possibly
3. I don't know, but not inexpensive.
I know, not very helpful. But your issue might be more simple - a bad electrical connection between the tank sensor and the instrumentation module. I am not as familiar with the wiring on the G1000 models as well as the VM1000 systems, but mine has at least two connectors between the sensor and the processor. My first step would be to clean and reseat these connectors. Let us know what you find out,
Steve
Re: Fuel Quantity Gauge failed
Posted: Sun Jan 16, 2022 7:06 pm
by Rich
Could be moisture in a sensor. If you have the 50-gallon version there are two sensors per side and additional connectors. Try everything else before replacing these sensors. I replaced one of mine years ago at the part price was $1,700.
Re: Fuel Quantity Gauge failed
Posted: Sun Jan 16, 2022 7:13 pm
by yl472401
Thanks for the heads-up. I'll wait for some warm weather in order to rule out the factor caused by coldness or freezing condition.
I did put covers over the wings for outside storage purpose.
Rich wrote: ↑Sun Jan 16, 2022 7:06 pm
Could be moisture in a sensor. If you have the 50-gallon version there are two sensors per side and additional connectors. Try everything else before replacing these sensors. I replaced one of mine years ago at the part price was $1,700.
Re: Fuel Quantity Gauge failed
Posted: Sun Jan 16, 2022 8:05 pm
by clsuther
I have been fighting the red X problem on my 2007 Diamond DA40XL for years. Most of the time I got no red X and was never able to recreate the red X on the ground even once. Sometimes I would get a red X just on the right fuel sensor and sometimes all my engine instruments would X out. We replaced the GEA71 twice and replaced the MFD once. Sometimes the problems would go away for months on end, only to return when I least expected. Once I would land, the engine instrument issues always went away. I took a video to show my mechanic that I thought it had to be a grounding problem or a short, because I could move the yoke and affect the X out.
https://youtu.be/2V9aGden48M
The Engine instruments began to X out again about 3 days ago and I was finally able to fix it. Another post had mentioned the wires leading to the fuel transducer. That was my problem, but I thought I would post some more in depth pictures. It is an easy check. Basically the wires leading to the fuel transducer are very susceptible to rubbing one of the screws that holds on the access panel. Somehow when there was weight on the wheels, it flexed the wing in a way that the wires never touched. We fixed the wires and everything is working perfectly now. I hope this helps somebody save a LOT of money.
Re: Fuel Quantity Gauge failed
Posted: Sun Jan 16, 2022 10:33 pm
by DavidShep
Happened in my '08 two years ago on the left side. AME cleaned and reseated the connectors. No issues since, after 300 or so hours.
Re: Fuel Quantity Gauge failed
Posted: Mon Jan 17, 2022 12:01 am
by yl472401
Thank you so much for the post.
Love the video you posted!!! It's like a ghost plane, LoL
I remembered there was some difficulty accessing the sump during the pre-flight check, might have had a forced entry
Anyways, I will check and see if those wires got messed up.
clsuther wrote: ↑Sun Jan 16, 2022 8:05 pm
I have been fighting the red X problem on my 2007 Diamond DA40XL for years. Most of the time I got no red X and was never able to recreate the red X on the ground even once. Sometimes I would get a red X just on the right fuel sensor and sometimes all my engine instruments would X out. We replaced the GEA71 twice and replaced the MFD once. Sometimes the problems would go away for months on end, only to return when I least expected. Once I would land, the engine instrument issues always went away. I took a video to show my mechanic that I thought it had to be a grounding problem or a short, because I could move the yoke and affect the X out.
https://youtu.be/2V9aGden48M
The Engine instruments began to X out again about 3 days ago and I was finally able to fix it. Another post had mentioned the wires leading to the fuel transducer. That was my problem, but I thought I would post some more in depth pictures. It is an easy check. Basically the wires leading to the fuel transducer are very susceptible to rubbing one of the screws that holds on the access panel. Somehow when there was weight on the wheels, it flexed the wing in a way that the wires never touched. We fixed the wires and everything is working perfectly now. I hope this helps somebody save a LOT of money.
Access-Panel.jpg
Wires.jpg
Wires-Close-up.jpg
Re: Fuel Quantity Gauge failed
Posted: Mon Jan 17, 2022 6:08 pm
by dant
FWIW I had water contamination that caused intermittent fuel gauge failure for a month at least, even with clean sumps.
It's been mentioned in other threads but these tanks REALLY hold on to water. We pulled a full gatts jar, waited 10 minutes, pulled some more, waiting again, and kept until it pulled smooth. Flew for an hour, with the gauge failing about halfway through, landed, waited a week, and then pulled ANOTHER full gatts jar out of it. Even with nothing more showing up it was failing. I ended up having the outfit that failed to reseat the fuel cap have their maintenance crew flush the tanks. They pulled another thimble of water out and haven't had an issue since. This was all off of one water event.
If you have fuel gauge issues and have any reason to suspect water contamination, get your tanks flushed. Actually if you have any reason to suspect water in your tanks more than rain entrance from refueling, get your tanks flushed.
Of note, we always operated on the known-good tank during critical phases of flight and other than maaayybbe a couple roughness "hiccups" never had any engine issues even on the contaminated tank.
(Lycoming)
Re: Fuel Quantity Gauge failed
Posted: Mon Jan 24, 2022 6:59 am
by yl472401
Thanks for the advice, Dant!
I haven't noticed any fuel contamination so far ( knock on wood). The gravity of the fuel contamination is well understood and that's has alway been a safety concern during my pre-flight check. I can see some particles suspended in the fuel and that could be some dirty from the outside environment. In that case, I would drain the sump again and make sure I got clear fuel from the outlet.
dant wrote: ↑Mon Jan 17, 2022 6:08 pm
FWIW I had water contamination that caused intermittent fuel gauge failure for a month at least, even with clean sumps.
It's been mentioned in other threads but these tanks REALLY hold on to water. We pulled a full gatts jar, waited 10 minutes, pulled some more, waiting again, and kept until it pulled smooth. Flew for an hour, with the gauge failing about halfway through, landed, waited a week, and then pulled ANOTHER full gatts jar out of it. Even with nothing more showing up it was failing. I ended up having the outfit that failed to reseat the fuel cap have their maintenance crew flush the tanks. They pulled another thimble of water out and haven't had an issue since. This was all off of one water event.
If you have fuel gauge issues and have any reason to suspect water contamination, get your tanks flushed. Actually if you have any reason to suspect water in your tanks more than rain entrance from refueling, get your tanks flushed.
Of note, we always operated on the known-good tank during critical phases of flight and other than maaayybbe a couple roughness "hiccups" never had any engine issues even on the contaminated tank.
(Lycoming)
Re: Fuel Quantity Gauge failed
Posted: Mon Jan 24, 2022 7:06 am
by yl472401
Follow up report on the fuel quality gauge issue. I followed clsuther's instruction today with some good result. I disconnect and reconnect those two connectors hiding behind the panel at the fuel sump site, turned on the power and found the fuel quality gauge to be functional. Temperature was 30 degree at the time and still cold, not sure the temperature was the ultimate cause of the sensor malfunction. I noticed the panel cover was misplaced previously and the round hold wasn't perfectly aligned with the fuel sump nozzle. Hope the problem don't come back again !