Dave,
Since it works using a separate battery to crank, I had kind of ruled out the CAS interference.  I think that it is either interference from the starter to the EC-2 from noise on the 12 VDC buss, or the voltage sag.  The power at the EC-2 drops to 10.6 volts while cranking.  This doesn't seem too bad to me, but something must be on the edge of operating.  I have to order some wire in order to power the rear buss from the forward battery, but I am going to repeat my separate battery test today, just to make sure that works consistently.

Steve

David Leonard wrote:

I think Steve is onto something here.  If you run the starter off the other battery, it is likely to solve the problem reguardless of cause just like your test run with an external battery.
 With reguard to the actual cause, I tend to side with Tracy in that is more likely to be CAS interference rather than low voltage.  I have left my master on for several hours.  Enough that when the started turned (and it barely turned) the voltage dropped low enough to really dim the cocktpit lights and shut down the music radio, but the EC2 had enough juice to get the engine going.
 Good luck!

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

 On Sat, Nov 21, 2009 at 10:40 AM, Steven W. Boese <SBoese@uwyo.edu <mailto:SBoese@uwyo.edu>> wrote:

   Steve,

   I was able to produce symptoms similar to what you describe by
   inserting a 1.5 V flashlight battery into the CAS return wire such
   that the CAS end of the wire was 1.5 V more negative than the CAS
   return wire going to the EC2:
   CAS ----- battery ++++ EC2

   The opposite polarity didn't cause problems.  With the battery
   installed, there are one or two sparks when starting to turn the
   CAS and then no more sparks until the CAS sensor is turning
   significantly faster than would be the case when turning the
   engine with the starter.

   It seems that you may have the CAS return grounded in addition to
   the connection to the EC2.  If this is the case, then the voltage
   drop from the starter current may shift the CAS return voltage
   similar to what I did with the test setup.  If I disconnect the
   CAS from the EC2 at the EC2 connector, all the CAS wires show
   infinite resistance to ground.  It might be useful to see if your
   wiring is similar.

   Steve Boese



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