Grt sport Efis eis and fuel sender issue

trackdom · #1 03-30-2016, 08:40 AM

Hi,
I am trying since a long time to get good informations from my fuel float senders
All I get is number 170 for the left tank and 27 for the right one. No change when tank quantity varies.
I disconnected today The wire from The left tank and got 55 .
It seems that all parts are grounded. There is just one wire to connect to The senders, it shouldn't be too complicated, but that doesn't work...? little bit frustrating indeed...
Thanks

Carl Froehlich · #2 03-30-2016, 09:03 AM

Here is an old thread on how to calibrate the float senders with the EIS.
http://www.vansairforce.com/communit...d.php?t=135121

If properly calibrated, the EIS will be within a gallon of actual when in the float range.

Carl

YellowJacket RV9 · #3 03-30-2016, 09:37 AM

You will need to follow the EIS instructions to set the offset and scale factors for each sender (0 and 100, I believe). Then, in the Sport you will set the fuel display to either 0-100 (for % fuel) or 0-max fuel. Then, you need to follow the fuel level calibration procedure from here: http://www.grtavionics.com/documents...%20Horizon.pdf

The instructions say Horizon but apply to Sport as well. Skip to section 3.2

It's a bit of a process but should get you sorted out.

Chris

trackdom · #4 03-30-2016, 09:50 AM

It's not a calibration issue, as I have no actual Numbers from sender to Eis.

YellowJacket RV9 · #5 03-30-2016, 10:12 AM

Have you measured the resistance of the senders to confirm they are changing as the level changes, and that they are within the expected range? I wouldn't expect both to be bad, however. We can assume they are connected to the EIS as disconnecting them changes the reading.

Did you wire them up with the resistor and 4.8v input as shown on the instructions? If so, and the senders are reading the correct resistances, then there are not many other issues besides a setting issue in the EIS or sport that I can think of.

Chris

trackdom · #6 03-31-2016, 12:03 AM

What I am sure is current comes to eis , but value never changes, 170 for left tank and 55 for right .
When checking ground I can observe that tank skin, sender frame and screw in The Middle are all grounded....

YellowJacket RV9 · #7 03-31-2016, 12:38 AM

The center screw should not be grounded, there should be a resistance between it and ground that represents the sender level. If it is really grounded (0 ohms between it and ground), there is something wrong. There should also be a voltage at the sender wire from the 4.8V that should be connected to it through the resistor as shown in the instructions.

If all of that checks out, and the EIS settings are all confirmed, you may have to talk with GRT. At the very least, I would go back and make sure every EIS and EFIS setting is correct and check all the wiring back to the EIS. The fact that both sides are not reading properly would suggest that either they are not wired correctly, or there is a setting or internal problem with the EIS. Are you reading the fuel level off of the EIS4000 or the GRT Sport display? If the Sport, can you check it on the EIS4000 and see what it reads? Good luck,

Chris

Bevan · #8 03-31-2016, 02:14 AM

Be sure to use a 470 ohm "pull-up" resistor as shown on page 46 of the following document.

http://www.grtavionics.com/User%...%20figures.pdf

Did you test the resistance values of the senders prior to installing in the tank to confirm they range from approx 30 to 250 ohms as the arm is moved through its full range of motion? One of mine became damaged after I installed it on the tank and had to be replaced cause the screw wouldn't tighten up. It just turned until the wire broke off on the inside.

Let us know what the problem was when you solve it.

Bevan

trackdom · #9 03-31-2016, 08:36 AM

No, I didn't mesure resistance before mounting the senders, and of course I don't want to dissasemble The tanks

Today I mesured left tank sender resistance , and I found 210 ohms, but eis and Efis indicate 170. So something is wrong in The connexions. I suppose The tank is 30 liters full.I Will empty ? little The tank to see if resistance changes.
Of course when The problem is solved I ?ll let you know .

skylor · #10 03-31-2016, 09:04 AM

Quote:

Originally Posted by trackdom

No, I didn't mesure resistance before mounting the senders, and of course I don't want to dissasemble The tanks

Today I mesured left tank sender resistance , and I found 210 ohms, but eis and Efis indicate 170. So something is wrong in The connexions. I suppose The tank is 30 liters full.I Will empty ? little The tank to see if resistance changes.
Of course when The problem is solved I ?ll let you know .

Also note that the EIS manual example step 1 on page 46 has you setting the Aux Forward/Reverse setting to "Forward", but I'm pretty sure (it was 6 years ago) that when I set up my RV-8, I had to set this to "Reverse".

Skylor
RV-8