There might be some confusion among the listers on carburetor vs. fuel
injection and Lycoming (Bendix/Precision Airmotive) systems and Continental.
On the Lycoming fuel injection system, with which I'm quite familiar, there
is no mechanical linkage that affects the air/fuel ratio.  What looks like a
mechanical link is there to control the idle fuel flow and it stops
affecting the fuel flow by the time the throttle is perhaps 1/3 open.  The
high load fuel flow is independent of throttle position and is normally
calibrated to be a fixed ratio of air flow (the mixture doesn't change with
throttle opening or with air flow changes).  There is a phenomena that
changes the air/fuel ratio, primarily on 4-cylinder engines, in that the air
flow pulsations can get quite large and can possibly go negative and these
pulsations are more pronounced at full throttle.  The result is that full
throttle mixtures are sometimes richer than part throttle mixtures.

Gary,

 

You've got to come for a ride with me.  Certain comments by Walter, Brent and yourself just don't quite match what I see in my airplane.

 

I am saving many of these e-mails in my engine management folder and the next set of data will be annotated by pertinent commentary.

 

Nobody wants to believe that my fuel flow increased when the rpm was reduced by 100 or the WOT MAP was reduced 1".  It did though, and my throttle body was overhauled just 2 years ago.

 

Air flow not have an affect?  Hmmmmm, you ought to watch my engine instrumentation as I level out after leaning in climb.  Dramatic change from the increase in air speed, thus the increase in ram air to both the induction system and injectors. 

 

Something is going on and I haven't been able to 'splain it.  I'm just going to keep collecting data - hopefully I won't run into anything while I'm head down and writing.