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


 Paul,

First, yes, the CAS wires are shielded.  They are run separately, away from
other wires.  But I can only separate things so far.  However, as you can
see they could be shortened a bit.

Here's another shot of the injector trace.  They are 60#/hr units x 6 ea.
 Since the engine was not actually running, the EC-2 would be seeing
atmospheric pressure, and so both sets of injectors were firing.

Mark

OK. My mistake. Kill that last message. The injector is on when
the voltage is near zero. The injector duty cycle is near
90%. No more fuel is possible at that fuel pressure.

Looks like the FET drivers need damping
diodes as you have that huge negative spike. I don't think that
has any effect on the how the system runs however but it is a major
source of noise.

At what RPM was this data recorded?

I scaled the jpgs so I could read the scope settings easier.

Paul Lamar