Need Spark Tuning halp, 86-87 Turbo Buick

[Marc Randolph]

On Thu, Aug 05, 1999 at 12:09:03AM -0400, ECMnut at aol.com wrote:
> My friend believes his keyway on the front of his Turbo 
> Buick crank is retarded two degrees.  This means the 
> crank sensor is also affected.   Is anyone aware of a 
> byte in the chip that would allow changing the "base timing",
>  so he doesn't have to change every location in the tables?

I'm not sure if it'll do exactly what you need, but the spark
reference angle is around offset 0x001B and is typically set
to about 0x11 (6 degrees) on Y-bodies.  ECMGUY's hack page 
shows an 86 Corvette with it located at 0x001C.  

It should be an entry or two before the maximum advance,
which is often in the range of 0x0078 (42 degrees), which
is one entry before the max retard (often easy to spot in
the PROM because it is a small negative number like 0xFFDC
or 0xFFF5 or some such thing).  This means the max advance,
followed by the max retard, would look something like the
following when viewed as a hex dump:

00yyFFzz

and would be located about 27 bytes from the beginning of the
PROM.

Anyone have better ideas?

   Marc

-- 
  Marc Randolph     -    mrand at pobox.com    -     PGP keyID: 0x4C95994D
     If you have any info on the mid-60's car called the Bill Thomas
       Cheetah, or know anyone that might, please contact me.