All that said,

 The computer problem you're having makes me nervous..  I hope you're
 RV-4 turns out to be the biggest success, demonstrating the great
 performance that I believe the rotary is capable of delivering!

 Matt-

 It is probably something simple like the mechanical relay that switches
 the injector drivers from one computer to the other.

 There are at least 50 and maybe as many as 100 Tracy computers like
 this flying. Most don't have problems like this. They are frequently
 hard to tune however due to the lack of a PC interface.

 Paul Lamar

 Paul,

 Is it possible to switch the two ECU's to put the "B" unit in where the
 "A"
 unit is now to verify it is not external?

 Dale Davies

 They are both on the same circuit board.

 Paul Lamar

 Paul,

 You may be getting spikes coming off the starter solenoid.  I put a spike
 catching diode on my starter to fix my EC-2 map table corruption problem.
 This was about a year ago and so far, so good.  May be worth a try.

 Mark S in Texas

 Good idea Mark. I'll schlep my storage scope out to the hangar and have
 a look. Mike put a large capacitor on there but perhaps it needs a
 diode or choke as well.

 Please draw a sketch of where you put the diode or send a pic.

 Paul Lamar

Paul,

I drew this from memory.  I'll double-check the circuit next trip to the
airport (Friday).

Thanks,
Mark S Texas

Thanks Mark. The polarity looks correct.  Was it a fast diode?

Paul Lamar

Paul,

I pulled it out of my parts bin.  I don't think it is anything special.  It
looks like something that would be used in an alternator, but smaller.
Sorry, I don't have a p/n.

Mark

Probably a 1N4001 1 amp or 02 2 amp.
If it was fast you would know it :)

Paul Lamar