K factor adjustment

[blueflyer]

from the manual: The general rule of thumb: if your GALS (or LTRS) USED reads higher than you expect, increase the K-factor; if it reads lower than you expect, decrease the K-factor

I have gone braindead. My D120 always says I have about 2 more gallons in the tank than actual. Sooooo, do I move my K factor number up or down?

 

[skysailor]

Is it the fuel quantity in the tank upon refueling which is incorrect or the amount of fuel you expect to add based on fuel used? Tank quantity accuracy likely lies in fuel transmitter calibrations. Fuel used being incorrect is K factor adjustment. These are two different things.

 

[dynonsupport]

The quoted passage is referring to the Fuel Computer, calculating the amount of fuel used using a fuel FLOW sensor.

But you seem to be describing a fuel LEVEL issue, which doesn't involve the fuel flow sensor.

Please clarify what you're referring to by "2 more gallons in the tank than actual".

from the manual: The general rule of thumb: if your GALS (or LTRS) USED reads higher than you expect, increase the K-factor; if it reads lower than you expect, decrease the K-factor

I have gone braindead.  My D120 always says I have about 2 more gallons in the tank than actual.  Sooooo, do I move my K factor number up or down? 

 

[blueflyer]

I was referring to the "fuel remaining" computation, not the fuel level.  Sorry for any confusion.

The fuel remaining calculation always says there are 2 more gallons remaining in the tank than what is actually in the tank. 

I know this because when I pull up to the fuel pump, I note how much the D120 says is "fuel remaining", and its always 2 gallons more than what's actually in the tank.

 

[dynonsupport]

Is it always exactly two, even if you only fill up with 8 gallons one time and 24 the other?

 

[blueflyer]

no, not exactly. Its just always showing more than whats actually in the tank by 2-4 gallons. I think I need to adjust my K value to increase the fuel burn, but I confused myself about whether I increase the K value to increase fuel burn or vice versa.

 

[jakej]

Reference to what you need to know is in the Install Manual under EMS Configuration - Fuel Flow

 

[dynonsupport]

Does it show more than is in the tank when you hit FILL? If so, then your fuel tank sizes are set wrong.

If not, as Jake says, the K factor adjustment procedure is in the manual.

 

[blueflyer]

Reference to what you need to know is in the Install Manual under  EMS Configuration - Fuel Flow 

Jake, please see post #1. Thanks.

Does it show more than is in the tank when you hit FILL? If so, then your fuel tank sizes are set wrong.

It shows the proper amount when I hit fill. I just need to know which way to move the k factor to increase the fuel burn!

 

[Dynon]

Decrease K-factor to increase the burn rate that it computes (you want a fewer number of pulses to equal a gallon)

 

[blueflyer]

much appreciated. Sorry I wasn't clear from the get go.

 

[jakej]

Reference to what you need to know is in the Install Manual under  EMS Configuration - Fuel Flow 

Jake, please see post #1.  Thanks.

Sorry, I saw that & I thought it was fairly clear.

 

[Andrew912]

When you add a second (return) Red cube fuel flow transducer to the return line of say an RV12, what is the procedure for the calibration of the "K" Factors?
The installation manual talks about the expected outcome using the second transducer but no mention of how to calibrate that i can see.
I have the return sensor connected to Pin 19 of the EMS C37 pin plug. i have have mapped the pin as fuel flow and set both PULS at 68,000. After the first flight and on start up for the next flight i received the fuel difference between used and indicated contents adjustment menu, (As well as the fuel flow not indicating the correct fuel flow i would have expected, so i need to make some adjustments to the "K" factor to correct the fuel usage. My question is which one do i adjust or do i adjust both? What is the procedure please?

 

[Dynon]

There isn't one. We'll need to think about this more to see if there's any good advice we can impart. The procedure for calibrating one sensor relies on the fact that you can compare what you're obtaining with the computer to what you know has gone through the sensor (the fuel you've put back in your tank during a fill-up). When you have two sensors, it's harder because you're not sure which sensor is the culprit when something is off.

 

[Andrew912]

Guys,

Thanks for the update. After running 3 hours worth of fuel (54 ltrs) through the new setup with both transducers set to 68,000 i was surprised to find the error was only 1.5 Ltrs. (Comp said 1.5 Ltrs more than actual) Initially i though it was much higher during the first 1.5 hrs of use the day earlier. Maybe there was still air in the line affecting it? (The RV12 has a restrictor in the return line at the firewall bulkhead prior to the sensor, so the fuel flow in the return line is quite low.) in the absence of a better procedure, based on the formula in the Dynon manual for a single unit i have adjusted the supply line transducer to 70,000 for the next trips to see where that takes me.

 

[fbush]

Erratic fuel flow indications

With over 100 hours of reliable operation on my Dynon EMS I recently noticed erratic fuel flow indications ranging from zero to normal f/f.  I still need to pull cowling and check wiring, but was wondering if I determine that it is a failure of the Red Cube can it be sent to the manufacturer for overhaul vice replacement?  In order for the installation to meet the requirements of the manufacturer I had to place the cube close to the engine exhaust routing.  I placed a shield on the exhaust pipe adjacent to the red cube and slid a fire sleeve over the cube itself.  Could heat be affecting the internal workings of the cube?

 

[tomkk]

I had the same symptoms. Checked installation, wires, connections, etc. Ended up replacing the unit and that corrected the problem. Don't know about overhaul possibility.

 

[Dynon]

I don't think that the sensors can be overhauled, but you might check with EI directly (the manufacturer of the sensor).