Dynon HDX Fuel calibration question

[bkc3921]

Getting ready for the 1st engine start on 912is. Thought I would calibrate fuel tanks as I add the initial fuel into the 20 gal tank. The screen promps me to add start empty, add 2 gallons, and so on. Does anyone recall how many “pours” it takes before the calibration procedure is done? Will I need to add the entire 20 gallons before the HDX is happy? I’m only asking because I‘m not sure I want it to be completely full on the initial engine start. Thoughts?

 

[Carl Froehlich]

The short answer is yes. This also verifies fuel capacity. Once done, use the fuel pump (via an inline filter) to pump the tank dry. This does a flush of the system, provides opportunity to verify fuel flow meets minimum specification, and once the pump loses suction you can sump the remaining fuel out of the tank. Subtract the sumped fuel from the total add and you have useable fuel.

Clean the fuel filter. If you have a bunch of crud in it repeat the flush until you don't. Do not run the engine until this flush is done. I use cheap clear plastic inline filters for this process.

Carl

 

[bkc3921]

The short answer is yes. This also verifies fuel capacity. Once done, use the fuel pump (via an inline filter) to pump the tank dry. This does a flush of the system, provides opportunity to verify fuel flow meets minimum specification, and once the pump loses suction you can sump the remaining fuel out of the tank. Subtract the sumped fuel from the total add and you have useable fuel.

Clean the fuel filter. If you have a bunch of crud in it repeat the flush until you don't. Do not run the engine until this flush is done. I use cheap clear plastic inline filters for this process.

Carl

Excellent reply and good info..thanks…I would like to ask: Exactly where do you place the inline fuel filter in the system ( if that makes sense)? As close to the engine as possible without sending the fuel to the engine itself? That way the entire system is cleaned? As, can you tell more more (exactly what kind) of cheap inline filters do you use?

 

[Carl Froehlich]

Excellent reply and good info..thanks…I would like to ask: Exactly where do you place the inline fuel filter in the system ( if that makes sense)? As close to the engine as possible without sending the fuel to the engine itself? That way the entire system is cleaned? As, can you tell more more (exactly what kind) of cheap inline filters do you use?

Correct. Disconnect the fuel line from your carb or FI body, add the filter to the line (may need some fittings) and add a line after the filter back to your five gallon gas cans.

You can use your existing filter if you like, just clean it afterwards. The cheap inline filters and associated standard auto fuel lines are available at auto part places, Walmart and such.

Carl

 

[bkc3921]

Correct. Disconnect the fuel line from your carb or FI body, add the filter to the line (may need some fittings) and add a line after the filter back to your five gallon gas cans.

You can use your existing filter if you like, just clean it afterwards. The cheap inline filters and associated standard auto fuel lines are available at auto part places, Walmart and such.

Carl

Thanks so much!

 

[PhatRV]

On my -8, I turned the fuel select to OFF before the tank level calibration.

After calibration, I drained the tank completely to flush out any remaining debris that was left inside the tanks during the build. Luckily, there wasn't any tank debris that I could find. Other have found a lot of aluminum shavings in his QB tank.

When I did the fuel flow testing, the fuel lines from the tanks to the inlet of the fuel servo would be flushed at the same time as the fuel was pumped from the tank.

When I poured back the fuel from the containers into the tanks, I also fashioned a filter made from coffee filter paper at the container filler tube to trap any remaining debris. The paper came out clean.