Programming 101

[Bruce Plecan]

If you just tuned in, please read the archives for all related 101
information.  This is for educational purposes.  Any prom editing
my violate federal state, or local laws, and is your responsibility to
find this out.  None of this should be done unless under adult supervision.
Please also read all the posts about tune-ups fuel
maps, timing tables, etc.  Addition bins for the 747 are available at
332 incoming.  Misapplication of this information may result in
terminal engine damage.  I am not an EE, or Software engineer, and
this is my opinion of how things work, and appear to work.
  When possible I've tried to verfify information, but not allows has
this been able.  Also, this material is 1227747 application specific.

The warnings are getting to be longer than the info..

When replying PLEASE edit the title so the 101 searches don't get
too overwhelming, and if repling to me please edit the reply of quoted
material.

Since there is no mechanicall choke on the 1227747 applications
of the TBI systems some corrections to timing fuel and air must
be applied.  These steps continue into what would be considered
overheating conditions also.  Since with any luck you won't be running your
engine under those conditions, and I wouldn't deliberately run an engine
there even for calibrations, I'm not even going to discuss these areas.
But, if you want to explore these areas, engines don't live long there, and
doing so is inviting serious trouble.  There are 9 steps for both the air
(idle speed), and AFR (air fuel ratio).  The idle speed temperature
corrections are at 060E-0616, and the AFR corrections are at  0459-0468.
The idle speed corrections are applied thru the IAC motor steps, ie the
higher the number as displayed on a scanner the farther the pintle is moved
from the closed posistion against the orfice.  If you look at the pintle,
that is on the IAC motor in the SBC applications, you'll notice that they
are a dual taper.  The second
taper starts at about the 155-160 count mark.  Also, replacing this
dual taper pintle with a single will slightly reduce the WOT air flow.
Also this Taper can be thought of having a slight affect on the
accleration enrichment.  I mention the above pintle and tapers for
those of you planning on using this info in dual throttle body applications.
If you measure things out you'll find the single taper
Cross Fire Pintles have about the same cross sectional area as
the single taper part of the SBC Pick-up applications.
  IMHO there appears to be a fairly large area of code devoted to
IAC pintle movement.  While commonly thought of as idle control,
and for anti-stalling, this accleration movement in correlation to
injector timing in light crusie conditions is very important.  Again
this is IMHO.
Cheers
Bruce              nacelp at bright.net