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Wiring Fuel Float

Karetaker

Well Known Member
Howdy everyone. I want to run wires from my GRT remote mounted EIS, (Engine Information System) to my fuel level floats, but am confused. The EIS Instructions say to use the instructions included with the fuel float. My fuel float is the stock Vans Stewart Warner, but I don't have wiring instructions. Later in the EIS instructions, there is a diagram for generic float wiring and that shows a 470 OHM resistor between the EIS 4.8V excitation wire and the EIS input from the sender. Anyone have a copy of the 385C Stewart-Warner wiring instructions?

Any help appreciated.
 
Page 46 of the installation manual is pretty straight forward.
The float sender has just the 1 terminal which you would connect the excitation wire/resister/Aux input wire to (per diagram on page 46).
Float sender ground is the flange mounting screws on the tank.
 
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Howdy Ralph. I assume you mean page 36, which is the page in question. Since I do not have the instructions that came with the fuel float itself, I was not sure if page 36 was appropriate.

I'll wire things together as shown on page 36 of the GRT EIS amd see what gives.

Thanks.
 
Howdy Ralph. I assume you mean page 36, which is the page in question. Since I do not have the instructions that came with the fuel float itself, I was not sure if page 36 was appropriate.

I'll wire things together as shown on page 36 of the GRT EIS amd see what gives.

Thanks.

I just looked up the EIS 4000 manual on the GRT website. That manual had page 46.
 
Thanks guys. I am using the remote EIS, which is the R66. Page 36 in that manual is the same as 46 in the other. I'll try it and see what happens.
 
there is a diagram for generic float wiring and that shows a 470 OHM resistor between the EIS 4.8V excitation wire and the EIS input from the sender.
.

That is what you want. Remember to attach a ground to one of the attach screws on the sender.
 
Mine for past 30 years has worked fine with no wire for ground. The unit is grounded via it being mounted to tank, wing, spar etc….
 
This is timely post. I'm trying to calibrate my GRT Sports now. I have the EIS-66R and the AuxSF and AuxOff I'm getting don't even come close.

Here is what I have so far, right tank.
Reverse sensing
EIS empty 13
EIS full 19 (This was at 17 total gals)

When I do the EIS worksheet (EIS-66R page 36) I get AuxSF of 260 and AuxOff of 67. That gives me a full indication of 46 (20 actual gals in tank). I was thinking my full indication would be 17. Something isn't adding up.

What do other RV8s have for AuxSF and AuxOFF for fuel.
 
My display is set to Integer so my readings full and empty have one extra digit. I got 135 empty and 189 full which are pretty close to yours if you set yours to Integer (I'm assuming your display is set to decimal). I got Aux SF to 30 and Aux Off to 79.
I struggled with the worksheet, there is a calculator for this on the GRT website for this. It's hard to find, if you got to the EIS R66 link, then go to the sensor documentation, the calculator is listed in the fuel level.
 
My display is set to Integer so my readings full and empty have one extra digit. I got 135 empty and 189 full which are pretty close to yours if you set yours to Integer (I'm assuming your display is set to decimal). I got Aux SF to 30 and Aux Off to 79.
I struggled with the worksheet, there is a calculator for this on the GRT website for this. It's hard to find, if you got to the EIS R66 link, then go to the sensor documentation, the calculator is listed in the fuel level.

Dave, Thanks for that info. I talked to GRT today and found out about the calculator. My display is set to integer so I just have whole numbers 13 empty, 19 full, 17 gals added. I used the calculator with my numbers above and get AuxSF 283 and AuxOff 73. The number above the tank says 46. Shouldn't that be 17 or 21? I probably have some other setting that is causing the 46 to show up. It's easy to get lost in the GRT menus.

I'll let you know when and how, once/if I get it working.

Thanks,
 
Victory!

I figured out my fuel calibration issue. As usual it was mostly operator error. The biggest issue was that I was using the calculator with Integer and the GRT Sport was set to decimal. So I fixed that and did the test again, twice.

The setting where EIS 13 - empty, EIS 19 - full with 17 gals added, I continued to 20 gals total. I plugged that into the calculator and set the AuxSF and AuxOff. I then started draining fuel. Unfortunately when the tank stopped draining I was still showing 1 gal.

I did a little trial and error to see what would give me an EIS 0 reading. EIS 13.7 showed -1, EIS 13.5 showed -0 and EIS 13.3 showed 0.

Reset and tried again with EIS 13.3 - empty, EIS 19 - Full with 17 gals added, I continued to 20 gals. I plugged the new numbers into the calculator and then set the AuxSF 298 and AuxOff 793. Started draining fuel and the amount I was subtracting (5 gals at time) was very close to the EIS reading. When the EIS showed 0 I stopped draining and moved the 5 gal can. I then starting draining into my 1 gal measuring pitcher. The remaining fuel after EIS 0 was 80oz or .63 gals.

I'm calling that calibrated. The left tank has a bad resistor so I'm waiting for a new one to calibrate that side.
 
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