Xicoy Fadec AU-107K problem - "Fuel Valve Overload"
10-12-2015, 07:35 AM
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Xicoy Fadec AU-107K problem - "Fuel Valve Overload"
The instruction manual simply says that "Overload" means that an excessive current is flowing to the specified output. I checked the operation of both valves via the hand data terminal and they both click.
Swapping the valves around and initiating a start (with fuel turned off to prevent flooding) produces the same message.
Removing the kero burner valve plug from the ecu and initiating a start generates the same message.
Removing the main valve plug from the ecu and initiating a start switches on the burner to begin the start sequence, presumably because no current is flowing in the main fuel valve circuit.
Removing both valve plugs from the ecu also allows the start sequence to begin.
So it looks as if it's the ecu and not the valves that's the cause of the problem. Does anyone know if there is any way of re-setting the ecu in this circumstance, or does it need sending back to Xicoy?
Gordon
Swapping the valves around and initiating a start (with fuel turned off to prevent flooding) produces the same message.
Removing the kero burner valve plug from the ecu and initiating a start generates the same message.
Removing the main valve plug from the ecu and initiating a start switches on the burner to begin the start sequence, presumably because no current is flowing in the main fuel valve circuit.
Removing both valve plugs from the ecu also allows the start sequence to begin.
So it looks as if it's the ecu and not the valves that's the cause of the problem. Does anyone know if there is any way of re-setting the ecu in this circumstance, or does it need sending back to Xicoy?
Gordon
10-12-2015, 07:29 PM
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Hello Gordon
I had an amperage issue with my starter, I contacted Gaspar and he gave me some settings to re-calibrate the ecu.
After that no issues at all. Hopefully that's all it is.
http://www.xicoy.com/catalog/contact_us.php Here is the email link on the webpage.
I had an amperage issue with my starter, I contacted Gaspar and he gave me some settings to re-calibrate the ecu.
After that no issues at all. Hopefully that's all it is.
http://www.xicoy.com/catalog/contact_us.php Here is the email link on the webpage.
10-14-2015, 11:25 AM
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It's right here, Edgar 
I did some solenoid resistance checks this afternoon, emailed Gaspar with the readings and my thoughts, and Gaspar replied almost immediately and explained the results.
Because “overload” indicates excessive current draw by the solenoid valve, I decided to measure the resistances of all the solenoid valves I possess. I have three Wren 44s, each with two identical solenoid valves of course. The engines started life as gas start, but in 2012 I upgraded them to kero start with Xicoy AU-107k Fadecs.
One pair of solenoids measured 28 ohms each, and a second pair measured 38 ohms each. The third pair, one of which was causing the overload indication in the main fuel line, measured only 16 ohms each. I bought the engines at widely spaced intervals from 2008 onwards, so the engines and ancillaries came from different batches, which explains the differences in resistances but not the reason why, which apparently was related to a change in Wren's supplier.
Gaspar explained that the 16 ohm valves are OK for use with older gas start ecus with which they started life, but are on or even over the limit of acceptable current draw for the newer Fadecs which check current draw and cease working if a defined current limit is exceeded. The old gas start ecus don’t check the current.
It appears that one of my AU-107k’s has a somewhat lower max current threshold than the others, and when I recently sent the engine, pump and ecu from my Hawk in for servicing, I replaced them in the airframe with my spare engine/ecu/pump set, but without exchanging the valves. It turned out that the installed valves were the 16 ohm ones, and that the replacement ecu was more sensitive to current draw than the one it replaced, and wouldn’t work. Replacing the low-resistance valves with the 28 ohm ones solved the problem.
Gaspar explained that I can use the low-resistance solenoid valves on the keroburner circuit as they are only operational for a short time. Only high-resistance solenoid valves should be used on the fuel side where continuous within-limits current management is necessary because the valve is in operation for the whole engine run.
A big thankyou to Gaspar for clearing up the puzzle!
Gordon
I did some solenoid resistance checks this afternoon, emailed Gaspar with the readings and my thoughts, and Gaspar replied almost immediately and explained the results.
Because “overload” indicates excessive current draw by the solenoid valve, I decided to measure the resistances of all the solenoid valves I possess. I have three Wren 44s, each with two identical solenoid valves of course. The engines started life as gas start, but in 2012 I upgraded them to kero start with Xicoy AU-107k Fadecs.
One pair of solenoids measured 28 ohms each, and a second pair measured 38 ohms each. The third pair, one of which was causing the overload indication in the main fuel line, measured only 16 ohms each. I bought the engines at widely spaced intervals from 2008 onwards, so the engines and ancillaries came from different batches, which explains the differences in resistances but not the reason why, which apparently was related to a change in Wren's supplier.
Gaspar explained that the 16 ohm valves are OK for use with older gas start ecus with which they started life, but are on or even over the limit of acceptable current draw for the newer Fadecs which check current draw and cease working if a defined current limit is exceeded. The old gas start ecus don’t check the current.
It appears that one of my AU-107k’s has a somewhat lower max current threshold than the others, and when I recently sent the engine, pump and ecu from my Hawk in for servicing, I replaced them in the airframe with my spare engine/ecu/pump set, but without exchanging the valves. It turned out that the installed valves were the 16 ohm ones, and that the replacement ecu was more sensitive to current draw than the one it replaced, and wouldn’t work. Replacing the low-resistance valves with the 28 ohm ones solved the problem.
Gaspar explained that I can use the low-resistance solenoid valves on the keroburner circuit as they are only operational for a short time. Only high-resistance solenoid valves should be used on the fuel side where continuous within-limits current management is necessary because the valve is in operation for the whole engine run.
A big thankyou to Gaspar for clearing up the puzzle!
Gordon
06-21-2018, 06:22 AM
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If anybody reading this thread can help? I have been trying to reach Xicoy to find out a way to reset the ECU to factory default (empty), but have not received a reply so far. I am trying to setup a ground test bed for a TJT3000 and in doing so the system is now not responding to the Test options from the data terminal. Any help on what to look for to get it running will go a long way. A big thanks.
