Hello Paul-

  Getting ready for 'first' flight again & we've been able to replicate the
  engine anomaly that was reported when we had our mishap last time.

  Seems that when the engine is running between 4000 - 4500 rpm & the
  throttle
  is smartly advanced, the engine will stumble for ~ 1 second before running
  steadily again.  We can replicate this with no problem -- it happens every
  time.  If the throttle is slowly advanced, the engine smoothly increases
  in
  rpm with no hint of a stumble.  We also tried this with the mixture set
  full
  rich -- stumble seemed worse / longer, and with full lean -- stumble
  seemed
  less, but did not go away.  If the engine is running below the 4000-4500
  range (say 3000) and the throttle is smartly advanced to WOT, the stumble
  doesn't seem to happen.

  We tried to track the MAP values to see if anything seemed odd during
  these
  tests.  Unfortunately, it seems we've developed an electrical problem with
  either the EC2 or the EM2 -- they're not talking to each other, so we had
  no
  way of displaying what was going on as the engine ran.  We spent a while
  debugging that issue & ruled out obvious causes.  (Tracy suggests we check
  for good ground between the two devices & it that is solid then they need
  to
  get sent back for testing).

  Do you suppose this behavior (the stumbling) just means we have more MAP
  adjustments to make (once we get the electrical issue sorted), or could
  the
  slide throttle implementation have anything to do with it?  Just trying to
  eliminate things to be checked...

  Thanks,

  Mark & Terry

  Move the throttle slowly :) Let them eat cake :)

  Does it happen during injector staging when the MAP is around 15 inches of
  HG?
  Making it richer in that area should fix it. Perhaps making it leaner as
  you already tried richer. It should have nothing to do with the throttle
  as you are measuring the MAP inside the rotor housing. Carbs handle this
  problem with an accelerator pump which temporarily richens the mixture.
  EFI's uses a throttle position sensor but Tracy does not like those.

  My C182 engine will stumble if you slam the throttle open. No accelerator
  pump on the carb. At least I don't think there is one.

  Paul Lamar


 Paul,
 this is why automotive ecu's have a throttle position sensor. The computer
 uses the injectors as the accelerator pump by increasing the pulse width
 momentarily above what the map has given.
 I don't think Tracy's unit supports this, but being gentle with the
 throttle
 does.
 Larry


 Mark, set the data acquisition system to 2000 samples per second and
 monitor the pressure at the output of the pressure taps on the rotor
 housings.



 Paul Lamar

Stupid me, I've forgotten which wires to hook up to the data acq system
(Which CAS wire goes to which sensor wire).

We had a big discussion about it when you were out here, but I didn't write
down what the answer ended up being.

Do you remember?  Or, how can I re-determine which ones to use??

 Mark

You just need two wires from the crank angle sensor. One ground and one hot.
The blue wire is ground and the green is hot.

The unit gets its 5 volt power through the USB cable from the notebook computer.
Also T's in the hoses coming from the rotor housing pressure taps.

Paul Lamar