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


That "large capacitor" looks like an electrolytic and they are good
for slow disturbances but you should have some HIGH frequency
capacitors across it .... and some more high frequency capacitors
right where the power enters the computer module.

SD


Good point.

Paul Lamar