That is strange. Tracy's engine works perfectly.
Are you sure your injectors are in good shape. Sometimes

they dribble

rather than spray.

Paul Lamar

I had my injectors cleaned and tested a year ago, the before and after

tests

were not much different.
Don't have a firm plan yet as to which day, when are going? We usually

use

123.45 for air to air comm.

Chuck,

    I have found in my installation that around 15-16" Hg

manifold and

approx 2800-3000 rpm that I need to program the system in much finer
increments of Manifold pressure and rpm than elsewhere.  If

I do not,

everything is fine at idle and everything is fine higher

than 3000 rpm but

as I increase from 2000 up through 3000 the air/fuel

indicator will shift

from rich to an lean indication and the engine will stumble

a moment.

Interestingly enough I don't notice it in the air.

Ed Anderson

Thanks, Ed I will try that. It is hard to get it to stay at a steady MP
around 16" because it appears to lean out as it drops below the staging
point, then MP increases and secondaries kick in again. It surges at

about a

one second cycle. I can stop the surging by manually richening the

mixture.

I don't notice it in the air either, except sometimes when throttled

back on

short final. Mostly does it on the ground when taxiing by onlookers :-)

Chuck Dunlap

I encounter the same conditions.  But, I find if I sort of ignore the MP
reading and advance the rpm in stages of 100-200rpm increments between about
2500-3000 and reset the processors MAP by using mode 1 so that the manual
mixture control set at 1200 gives me a rich indication on the air/fuel meter
that takes care of the stumble.

Ed Anderson

Tracy needs to put a bit of hysterisis(s?) in the software.
Either that or gradually transition from two injectors to four.

It is easy to get theses kinds of control problems when using computers
in real time closed loop systems. There are delays in certain sensors.
Perhaps the MAP, perhaps the intake manifold temp (highly likely) perhaps 
even the RPM (somewhat likely).

Try moving the throttle very very slowly.

Paul Lamar
 
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