All,

I have Wren 75 with a Xicoy FADEC AU-107K ECU. Up until this year everything has been working great. This year though I have not been able to get my turbine to start. From what I can tell the fuel pump is not running during the start process. The system starts, the starter begins but the ignition fails error message pops up on the display. The glow is hot. BTW, its a auto kero start.

I pulled the lines and no fuel is flowing. If I manually tested the fuel pump using my data display interface and it runs fine. I reversed the solenoids to and both seen to be working well. My my position of ignorance I have to think that there my be an ECU problem.

When I manually test the fuel pump, it does make a bigh pitch sound that I don't remember.

Does anyone have any ideas of what I should check next?

Thanks in advance for any suggestions.

Don S.

Don,
Go to" pump power at ignition" and increase the value until your engine starts. I normally do
2 points at a time. Good luck.

Johnny

Johnny,

Thanks for the info. I will try that in the morning. My follow on question would be: why would that value change? I haven't touch my ECU parameters for years and things were fine.

Don't get me wrong...I am definitely going to increase that setting.

Thanks much for the help!

Don

If the pump did not run for a while it might have gotten gummed up a little, which causes the very little fuel required for the kero start to not move at all. Run it in a closed loop for a while and it might get better, you also get to make sure it doesn't quit on you when you go fly if it did get damage/worn out.
If you do increase the pump value at start, keep your extinguisher ready as after a few flights if the pump frees up you might get flames (and need to dial it back down)

It's very easy to check.

1) Pull the wire for the pump, and hook it to a small battery and see if it spins. (hook your fuel line in a loop so you don't flood the engine) A single cell lipo is fine.

OR...

2) Put a meter on the ECU pump wire, and try a start. If you see voltage, the ECU is probably OK.

One of those will lead you to where your issue is... but sometimes a pump will stick. SO... put the battery on one direction, and then reverse polarity to get it to spin backwards. Some times that will free it.

I had a JetCat 80 (gas start) that would light on the gas but would not ramp up. First flight of the day was always a big problem, but after that it was fine.
I put a little dot of Tippex on the visible end of the pump motor shaft, then scraped off half, so that I could see that the pump was turning, and often it was not, after lying for a while.
My solution was to run the fuel pump on an external battery, or on the test cycle in the ECU, for a few seconds before attempting to start. It seemed to free off the pump and subsequent starts were no problem.

The pump on my Wren K100 will stick, too. I just tap on it with my trusty Swiss Army knife when doing the first start of the day, and it will start running.

All,

I really appreciate the information that you guys provided me. I was off today and was able to spend time with my turbine. I adjusted the pump power at ignition and was able to get my turbine started and running smoothly.

I tried Terry's tap with a Swiss Army knife approach first but no luck. I had to adjust my ignition value from 28 to 47 before I got a satisfactory start sequence going. That's the good news. The bad news is seems like a pretty significant change so I will be watching that really close.

During my testing I did get one small wet start but was able to blow it out with power...no big issue.

Again, thanks for the help. I have learned a great deal from the process.