Tune-up items

[bruce plecan]

Thought I'd spend some time today, and share
how I do light throttle criusing set ups, for 
DIY programs using GM ECMs.
  Just as a reference for this I'll be using a slightly
hotter than stock cam, healthy ignition and assume
some roughing out of the fuel timing tables have
already been done.
  The objectives I look to attain is using as much timing
as possible consistent with min, throttle opening, and
using jus enough fuel to run 128 or slightly lower BL
numbers.
  So for monitoring a DVM is attached to the TPS, a
scan tool is hooked up for looking at BL, and a 10
element LED AFR display is attached with this
wired up it real easy to now stat adding timing to
the 40 kpa areas by rpm for the cruise are of the 
ignition map, then watch to see if ya run 40-45
kpa or 35-40, depending on which side your on
then drop off as much timing going to the 20
side (overrun), which richens the O2 readings 
and helps to cut the fuel on overrun, so the car
slows when you take your foot off the gas.
On some of the oems you almost have to hit the
brakes to decell the car.
  Then from the 40-50, again depending on your car
I drop off as little timing going toward 100 kpa, as 
possible, again running enough fuel so that when
pulling slight grades the motor don't chug (love that
technical lanuage).  Then I use a min. amount of timing
for the WOT spark adder.
  The little things I like to do is stay on the low side of
the 128 at cruise so the engine is instantly smooth
and pulling when I nudge the gas.  Their is no difference
in MPG between this and 128.  The MPG is almost a
dead 1:1 with min TPS. If you have the capability for
PWM of the EGR I'd turn this off during the initial
tinkering so that you don't chase too many items at
one time just doing the spark and fuel can be an
exercise in patience.  ALSO JUST OFF idle and
just as you go to light cruise at say 30-35 mph
you may have a for dodo (in this area of dodo BLs
are lousy reguardless of timing afr) area with a big cam,
when the engine first wakes up and the tract 
lenghts start to work, and the engine is reducing
it's self egr at low speeds.  If ya can pull from
1600 rpm in high gear smoothly from a roll
that might be the best ya can do, some just
don't like to lug down to 1400.  
  Do at the light throttle cruise initial tuning in
whatever gear is 1:1, or less (overdrive) 
giving the engine the advantage of gearing
might leave you having to do a major retune.
  On some of the programs you can lower the 
TPS enable settings.  If your running an auto
tranny watch it,  If you have a TV cable 
sensing tranny ya wanna have enough line
pressure increase to keep from smoking the
tranny do to the extra HP at low TPS settings.
  I posted my fuel map the other day, if some
e-mail me I'll post the spark,  jus getting to
be a big use of BW
  Hope ya all find this interesting if not let me
know and I'll stop
  Bruce  Only a cone hat wearer would put this
             much time into the light cruise area