ELECTRONIC  FUEL  INJECTION

EMC
The ECM used by Howell is the 1227747.  It is the most widely hacked ECM that GM produced.  There are tuning programs and dis-assembled code available on the Internet

Check out
http://www.diy-efi.org/gmecm/
more specifically
http://www.diy-efi.org/gmecm/ecm_info/1227747/

TUNING
For tuning information check
http://www.geocities.com/ecmguy.geo/bruce/prog_101.html
Manuals are at
ftp://ftp.diy-efi.org/pub/gmecm/manuals/1227747/

If you use one of the tuner programs you will need the .ecu files.  These define the location of the various tables in the PROM.  Dave

Tuner Cat
http://www.tunercat.com/index.html

Error Codes
http://209.145.176.7/~090/awh/dtcobd1.html#sys

Its not a bad idea, as it has some smaller perks- running right on 14.7:1 gives less than ideal emissions and can be a bit sensitive to ping etc. You can go quite rich before you significantly impact economy, even at ~12:1 it would be very difficult to measure a consistent drop in fuel economy to any degree, and might even permit enough extra ignition advance or compression on a given fuel octane. Exhaust valve temperatures vary almost perfectly proportionate to mixture strengths. Volumetric efficiency is expressed as a percentage, the theoretical amount of air that the engine should be pumping at a given RPM divided by the actual amount of  air that the engine is pumping. Brent Covey