Paul,

We ran the "bench test" on the EC-2 today, turning the CAS trigger wheel
with a variable speed Shop Smith wood lathe.  This allowed rpm adjustment
from approx 1900 rpm to over 6500 rpm.  I've enclosed some pics of the
setup (IMG_0358.jpg) and the related scope traces (IMG_0365.jpg).
Voltage
measurements at the sensor pins (before resistor) were as high as 41v,
but
were a max of 8.25 at the zener diode/22k resistor.  The majority of the
tests were with the CAS sensor gap set to .040 as this is what Bobby
Hughes
measured the gap at on his Renesis.

The really strange thing, which I need Tracy's opinion on, is that the
EM-2
would only read correct RPM up to about 5800 - 6000 rpm.  This is
about the
same place where the engine starts cutting out.  At that point the
readout
went crazy and would indicate anywhere from 0 to 6300, and anything in
between, and constantly changing.

We put the scope on the injectors and have included those traces too
(IGM_0363.jpg).  From what we could tell, the signals looked good up
to 7500
rpm.

We also tested that the coils/plugs were firing up to about 8500 rpm
with no
obvious problems.  Of course, this could change when under compression.

Another thing that we discovered is that RPM's on the EM-2 would not
indicate correctly unless we powered the injectors during the test.
RPM's
were verified with a handheld laser tach.

Since all of this began after converting my EC-2 to Renesis style CAS, I
think my next step is to borrow Bob Darrah's EC-2 and try it on my
engine,
using the second gen CAS.
Mark

Nice Scope.
http://www2.tek.com/cmswpt/psdetails.lotr?ct=PS&cs=psu&ci=14408&lc=EN

Something is going on in the software. I suspect it is a time
related interrupt problem. Tracy may be using the software
to decode the RX8 wheel and the processor is just not
fast enough.

Good work guys. Way to go. Now we are getting some where.


I will do a littler hard ware decoding of the RX8 wheel
this weekend and see what I can do.

I do agree that unshielded RX8 CAS wires will pick up
interference. I had 3 foot wires on there and
hooked up Craig's function generator with a square
wave at 3 Mhz and a 3 foot long antenna. I got
about 1 volt peak to peak noise on the CAS wires.

The first thing you must do is shield that CAS
signal wire.


Paul Lamar


Hey Mark;
Grounding/shielding are common problems with both stock and aftermarket.
Is that CAS wire shielded?
Does Tracy recommend grounding the CAS wire to the ECU?
Any ferrous metal nearby could also be bad.
Cheers
Cary