EGR Corrections

[Bruce Plecan]

Over the years I heard of all kinds of terms for EGR Valves, negative
pressure, posistive pressure, backpressure, etc..  And all the while
"they" from factory tech reps, to vocational teachers, have always
expressed the since there was no signifagant manifold vacuum that
the egr wouldn't apply.  Well in the wee small voice in the back of
me head I always wondered about exhaust backpressure opening
it.  In the little realm of CSH engineering and design there have been
various experiments that seemed to indicate that they were in use.
In starring at some tables while taking a break from the bench ecm
project, it seems like this one spark table is a correction for timing
for egr and runs from idle to 100K/Pa, and up to 4,800 rpm, at 100
K/Pa.
  Again this is gm specific, and is there anyone who'd care to
comment?......
Cheers
Bruce        Federal Judge has told the Staff at CSH,HQ that no
                  strikes will be permitted since this is considered to
                  be a national security industry.  Just the rumors of
                  a strike here crashed the New York Stock Exchange
                  400 points this week.