GRT Avionics

I have the EIS Model 4000/6000 Users Manual (Rev K). Figure 5a shows the pinouts for the female D-sub connector. It appears that Pin #8 (Yellow/Blue Wire) is not labeled. What is this wire for? Thanks.

Yellow wire with the blue stripe is for the fuel flow return.

GRTBen,
When you say Fuel Flow Return....is this for fuel injected engines? Can you elaborate more?

Or is this related to the FloScan Sensor?
It doesn't seem to be since the 3 wires there are:
FloScan
RED = EIS Pin 13, Connector A (+12V Regulated Power, EIS RED/GREEN wire)
WHITE = EIS Pin 14, Connector A (Fuel Flow Input, EIS WHITE/GREEN wire)
BLACK = FloScan Ground wire (I've connected back to EIS4000, Pin 1 Ground using a Raychem solder sleeve pigtail)

Howard

It's for a second flo scan sensor. On fuel injected TCM engines lots of gas is pumped to the controller, and the excess goes back to the tank thru a return line. So you need a flo scan on both lines, and the EIS takes the difference to get the net fuel being used. Lycomings don't have a return line, so just one sensor needed.

I think that only applies if the transducer is located before the mechanical fuel pump (where the return is). If the transducer is located after the mechanical fuel pump, a second transducer is not required.

A few years back, Sandy sent me a configuration drawing for the Eggenfellner engine installation when I switched from Carb to EFI. I had to send my EIS unit back to GRT to have the firmware updated, but now it measures the fuel injection pulses for fuel flow. No need to measure outflow and inflow lines. This method has been very reliable.

==
Michael
Sonex N293SX

Bobturner wrote:It's for a second flo scan sensor. On fuel injected TCM engines lots of gas is pumped to the controller, and the excess goes back to the tank thru a return line. So you need a flo scan on both lines, and the EIS takes the difference to get the net fuel being used. Lycomings don't have a return line, so just one sensor needed.