Tech Puzzles

[wypaul 456]

Ok. So let’s see if there is any interest in this idea.  I’ll start this off.

so I’ve had some issues that were driving me whacky.  Avid with a Rotax 912ULS.  #1 I have installed SDS fuel injection.  I would get an occasional map sensor fault.  Changed out the MAP sensor and checked the wiring no joy, didn’t change performance just cleared it and keep on flying. This started over a year ago.

#2 this spring my tach started reading high above 5000 RPM.  Sometimes floating as high as 13000 or so, Indicated with my MGL Blaze engine monitor.

#3 Radio issue MGL V6 radio.  Radio started tripping out a month ago, lights on but nobody home.  I could reset it by turning the power off and back on but this radio has no on/off switch so in the air it entailed shutting down the the engine due to the EFI setup.  I did not like doing that so I added a comm power switch.  Noticed a bit of background static some months back when receiving.

So there are the puzzle  pieces anybody interested in solving these puzzles?  I will say that I have solved these puzzles and will offer up the solutions in a few days but let’s hear what you think.

[1avidflyer 2003]

I'm horrible at electronics, so I won't even guess.  Interested in the answer though.  JImChuk

[Avidventurous 22]

I wonder if the radio shutting off is an over voltage protection. I know nothing about the radio however that over volt could be a very short duration, not long enough to read with a meter for instance. I'm just guessing here, so take this with a grain of salt....

[wypaul 456]

I wonder if the radio shutting off is an over voltage protection. I know nothing about the radio however that over volt could be a very short duration, not long enough to read with a meter for instance. I'm just guessing here, so take this with a grain of salt....

ok I won’t drag this out any longer.  You are on the right track.  I had that issue with the fan motor on my heater. Installed a diode across the leads to solve that spike or back emf.  These problems we all caused by a bad resistor spark plug cap that Rotax uses, open circuit.  Removed the caps from each of the spark plug wires and tested them with the ohm meter.

Anybody else have some strange issues that they solved, let’s hear them.

[Avidventurous 22]

IF it is a short duration voltage spike, you might be able to suppress it some with a low impedance capacitor like a Mylar or something similar. 4.7 µF 50 or 63 volt might work. Put it as close the DC input on the radio as you can. Justathought

[wypaul 456]

I believe that it was radiated energy from the open high tension ignition lead in this case.  I believe your solution would work but now the cause has been resolved.  Thanks I will keep that solution in my memory banks for future reference.