Have you read the maual of this problem?

I understand you have a FADEC from Gaspar Espiell in Spain?
This is a very good ECU, as it is a Full Authoroty Digital Engine Control, allowing you to do anything to any micro radial jet-engine.

If you have, check the pump batteries on a good charger to tell you what the batteries is capable of by a test at the discharge menu. OK?
Is it a three or four cell pack?
What are your max rpm setting?
What cind of pump?
Are the fuel-flood free whith no failures or restrictor-effect? (Full filters or hard bends on the fuel line) ?

You may program it whith the engine off, to check the all the parameters at start and full throttle.
Just set the max temp lower than the actual air temperature, and this allowes the pump to start.
The air temp shows in the first screen. Do this at cold engine.
Next, disconnect the fuel line to the engine, and put this back to the tank.
This gives the same level in the tank as you perform the test.
Once rising the throttlestick, you will be able to the test the settings as long as you like, and hopefully, you will detect the problem.

Give full throttle, and take your time to have control of what is happening.
The LED should blink now, but if it don`t, there is absolutely no problem to mail Gaspar about it. He is a very cind person, who takes care of his customers.
But if you don`t perform this test ahead, he will make you do this.
But I doubt the ECU itself is the problem.

Hope this helps you out on this one.

Gudmund