No Lane Lights, No ECU

Jeff,

Here are the results of my test...

Between Regulator B and the airframe, with the OHM Meter set at 200, I get a reading of "00.2"

With the Backup Switch ON (Master ON), and the OHM Meter set at 200, I get a reading of "OL."

With the Backup Switch OFF (Master ON), the Start Switch ON, and the OHM Meter set at 200, I get a reading of "OL."

With the Master OFF, red lead on Terminal #3 on the X3 plug, black lead on the Regulator B ground plate, I get "0.00" volts.

With the Master ON, Backup ON, red lead on Terminal #3 on the X3 plug, black lead on the Regulator B ground plate, I get 13.46V  (same reading with the Backup OFF)

With the Master ON, Backup OFF, red lead on Terminal #2 on the X3 plug, black lead on the Regulator B ground plate, Start Switch ON, I get 13.55V (0.00V with the Start Switch OFF)

Any thoughts?

Thanks so much for this help!

With the Backup Switch ON (Master ON), and the OHM Meter set at 200, I get a reading of "OL."

With the Backup Switch OFF (Master ON), the Start Switch ON, and the OHM Meter set at 200, I get a reading of "OL."

Rob

Both the backup up power switch and the start switch should be two-pole. One pole connects 12+ power to the Rotax fuse box via the X-3 Connector, and the second pole connects the engine ground (EMS Ground) to the airframe ground (see marked up diagram attached). In effect, the second pole of each switch ties the regulator A ground plate to the regulator B ground plate, and by extension to the airframe ground.

Based on your testing, this circuit is not working or not yet installed on your aircraft.  All engine functions and the fuel pumps are grounded to the regulator A ground plate, so if it is not connected to the airframe ground during the startup cycle nothing will work. Once the engine starts and the generators take over, this ground connection between the airframe and engine systems is no longer needed (or wanted) and is thus disconnected when you turn off the start power or emergency power switch.  Both should be off once the engine starts in normal operation.

For normal operation, think of regulator A as the power source for the engine electrical system, and regulator B as charging for the airframe electrical system.  Normally the two are isolated, but must be connected together to get the engine started.  This is because the battery must power the engine systems until the generator takes over. 

Jeff,

I really think you are helping me and I appreciate your time.  

If I could, I would like to show you what I am seeing now.  

I do believe this is a ground issue of some sort.  But I am electrically inept.  

Here are two pictures:

1. Is the drawing for my avionics.  This shows a ground coming from the back of both switches going to "Airframe Ground".  I have disconnected these as you will see in the next picture.  Its seems to me these are not appropriate.

2. Are the actual Backup and Start switches.  You can see the ring terminals with the red insulation that have been pulled off

Unfortunately, this has changed nothing and I still have no ECU.

My problem is that I take drawings/schematics like this quite literally.  I believe there are many assumptions in what is being depicted, but I am unable to discern what should and shouldn't be.