Mailing List flyrotary@lancaironline.net Message #40712
From: Al Gietzen <ALVentures@cox.net>
Subject: RE: [FlyRotary] EC-2 troubles
Date: Sun, 16 Dec 2007 16:50:39 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

Mark;

 

Yes; been there, done that.  Seems unlikely to me that it is caused by the solid state relay, but . .. . I have a standard relay for staging, and have always had seamless staging and no issues with that; but I had serious issues with corruption of settings – MAP table, pulse setting, staging point all corrupted at various times.  Wiring changes to eliminate possible noise pickup from other leads seemed to help, but didn’t solve it.

 

Finally added the following changes to the board:

 

1000pf capacitors were added to:

 

All fuel injector signals

All ignition control signals

RX input

TX output

 

47uf, 16V tantalum were added to each processor

 

Pin 8 of connector is now grounded.

Pin 28 of connector is now grounded.

 

That solved the problem for me.   As we were making these changes and analyzing causes, both my son (my expert) and Tracy began to think that that isolation diodes I have in the power circuits, to the EC2 and the injectors and coils, to maintain independent power redundancy; likely exaggerated the problem by not letting noise travel back to the battery (the big filter).  We never confirmed this; but likely you would not have to go to the same lengths in filtering if you did not have diode isolation of the circuits.

 

Four more hours of flight time this week – just past 75 hours.  Real happy with my cruise at 200 mph (TAS) and 22 mpg.

 

Al         (Velocity RG 20B)


To refresh your memory, I recently installed the solid state staging relay on my 20B Lancair ES.  When doing the install, I didn't reinstall the diode (to ground).  During a short test flight after installing the solid state relay, the map table got corrupted.  I wrote for your advice and you instructed me to connect the diode.  I reinstalled the diode to the staging relay and went for a short 30 minute flight today.  The "A" map table again got corrupted.  Switching to the "B" controller resulted in a smooth running engine.  After landing, I entered the EM-2 tracking mode and it was obvious that the "A" map table was again corrupted.   I have not reloaded the default map, in case you would like to take a picture of the EM-2 display of the map table.

These are the only two instances of this happening that I can recall, both cases happened after I installed the solid state injector staging relay.  Could the relay possibly be related? 

Also, I understand that others with composite a/c have had problems similar to this (sporatic corruption of the MAP table).  Have you been able to determine a common cause?  Any suggestions? 

I am posting this to the fly rotary group in hopes that someone on the list may have already "been there, done that". 

Thanks,
Mark S.



 

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