Fuel level sending unit.

[NAH7853]

When the long range tanks are full the G1000 gauge works fine until the indicator gets to the 16 gal mark. Then the LH fuel indicator gets a dreaded red X. I was told that there are two fuel level sending units on each wing. One in each tank. I would like to get the "most likely" part ordered so the work can be completed later this month. Has anyone had a similar experience and be willing to share the outcome?

[Steve]

Can't help with a P/N, as I don't have the G1000 system. On a more general note, I would guess that the sender is an expensive part. I wouldn't buy one unless you knew it was bad, or could return it (unless you want to have an expensive spare on hand). Your problem may be as simple as a bad or dirty connector.

I just completed the annual on my airplane. I was having a problem with the magnetometer not slaving the gyro. I unplugged all of the electrical connectors between the magnetometer and the slaving panel, and those between the slaving panel and the gyro and used some Stabilant® on all of the pins. Don't know which connector was bad, but that seems to have fixed the problem.

Just my 2 cents...

Steve

[BlueYonder]

I had a total failure of the left fuel sender on my 2007 XL last spring. The A&P checked everything very methodically -- fuel lines, connectors, etc. -- before deciding to take off the wing (which is the expensive part of this process, though the sender itself isn't cheap, either). Took about 2 weeks to get the new part, another week to get it in and put the wing back on. So that was it for flying in those gorgeous May skies. Be grateful this is happening in December!

I was up at the end of November when the big red X appeared again on the fuel gauge -- this time on the right side. This time, the sender is fine; it's a problem with the G1000 unit itself, the component that gathers info from the sender and displays it on the MFD. She's in the shop right now; hoping to have her back next week. Turns out I'm also running a version of the G1000 software from 2009, so there will be updates there as well....

[NAH7853]

Mine just happens to be a 2007 XL as well. It took forever to get parts out of Diamond for my annual in October and was trying to get a jump on the process. Diamond "recommends" replacement of the hoses between the tanks at 10 years. I can't see where anyone actually did this as a maintenance item on the forum but would probably do it if the tanks have to be pulled.

[ThomasD]

I had the same on my 2007 XL as well, LH wing, on the inner tank. The maint shop had to pull the wing. There are several part numbers of bits you need - PDF attached for the work I had done in Feb this year.
Total cost around US $4k: labour around $1.5k; parts $2k; plus tax on the total.

[Rich]

It is possible to test the sensor without removing the wing. But yes, these things are expensive. My sensor unit cost $1,700.00 - plus the labor, of course.

[ThomasD]

Yes, the shop I used confirmed that the sensor was defective before ordering the replacement (without pulling the wings).

[Chris B]

FYI, if you are replacing the fuel sensor you may want to check this thread from 2013: link

It is surprisingly easy to screw-up the fuel sensor installation.

Chris

[NAH7853]

Thanks for the information. I am still recovering from my 10yr annual along with an ADS-B upgrade. While I had really hoped for an easy solution I guess this will force me to change the tank hoses when I do the transducer, which is the only recommended maintenance left undone... If there is any bright side, Infinity Aviation is a Diamond Service Center with experience working on DA40's and is only a few hangars down the taxiway at KASH here in Nashua, NH.

[Karl]

First thing is to clean all plugs and connectors.
Test the fuel level sensor from the plug to see if it is at fault.
If it looks like the sensor is faulty, flush the fuel tanks.
These sensors are prone to issues if there is any water in the tanks.
A test we did after an engine failure showed almost 1lt of water can sit in the tanks that cannot be removed via the usual water sediment drain.Of course I have never found that much in a tank in normal use but it is possible.

One poster stated a week to change the sensor. Seems a bit much we usually turn it around in under a day if spares are available.