K factor and fuel flow calibration

[Andy]

FX-3 owners - Have you found the default K factor of 68,000 to be accurate? If not, what corrected K value are you using?

Despite several K value adjustments my G3X fuel used is always greater than actual fuel used. My flow sensor wiring is supported by spark plug wires and I suspect the GEA 24 may be picking up spurious pulses from the ignition system.

[aflyer]

I am using the default value for K factor, and it works perfectly. My EX-3 has everything the same, the red cube is in the location on top of the servo the same as in the build manual. I ran the wires myself and I was careful to keep them away from primary and secondary ignition wires, so you may be on to something there.

John

[Andy]

Thanks John. That's a useful data point that seems to indicate that the non-compliant installation of the flow sensor is not the cause of my flow errors.

The image I posted showed the sensor wire routing as installed at Yakima. When I removed my servo for inspection I removed the sensor and its pigtail with it. I used the same wire routing when I put it all back together but I tried to achieve better separation between the "stand-offs". Maybe that reduced any pulse coupling.

I plan to re-route the flow sensor wiring next time I have the lower cowl off.

[kshunz]

The default for my FX-3 (CCX-2000-0148) is 30000. I did some careful measurements over the first 400 gallons of fuel, and decided that was darned close. Maybe 29500 might be a little closer, but I left it at 30000.

Scott

[Andy]

The default for my FX-3 (CCX-2000-0148) is 30000. I did some careful measurements over the first 400 gallons of fuel, and decided that was darned close. Maybe 29500 might be a little closer, but I left it at 30000.

A default of 30000 seems to suggest your FX-3 is not using the EI-FT-60 "red cube" flow sensor. Do you know which flow sensor is used on your FX-3?

[JimmyV]

on my carbureted SS i adjust k factor at fuel fills comparing amount of fuel added, to what the G3X flow meter says i had used - after several fine tunes its extremely accurate. I have to be careful to "float the caps" each fuel fill. Its works well. I keep it just a touch to the conservative side.