More DIS-749.bin stuff

[Tedscj at aol.com]

Here is a copy of some email someone sent me based on their observations.
This matches what I've seen.

Ted

Maybe this will help.  If not, at least the artwork's cool.

Here's distributor based signals as I remember 'em. Read it with a
fixed font, word wrap at 70 chars.


1) Pickup coil generated analog signal
2) Reference out from module (in EST mode)
3) Signal to module from ECM

pulse#    1                   2                3                  4

      ^^                 ^^                 ^^                 ^^
    ^   ^             ^    ^             ^    ^             ^    ^
--^     ^      ^----^      ^      ^----^      ^      ^----^       ^  
        ^    ^             ^    ^             ^    ^              ^  
        ^    ^             ^   ^              ^   ^               ^   
          ^^                 ^^                 ^^                  ^
pulse# 1                  2                 3                 4
                                          	                           
    ____               ____               ____               ____
   |    |             |    |             |    |             |    |
___|    |_____________|    |_____________|    |_____________|    |__
          
                                                                    

Pulse#                                                                     
  4                  1                 2                    3  
                      
 _____   (delay)     ____               ____ Spark         ____   
|     |             |    |             |    |             |    | 
|     |_____________|    |_____________|    |_____________|    |__    
                         Dwell period
 



This is roughly what your 3.1 signals Could look like, in the same
order.  I know the first is correct for the crank signal.


Cyl#  
(ref)      6                 1                   2  


v    v--v    v--------------v    v--------------v    v--------------v
 v  v    v  v                v  v                v  v    
  vv      vv                  vv                  vv     
                             
pulse#       6                 1                  2                
________           _________           _________           _______     
        |_________|         |_________|         |_________|       |__

    
pulse#
                                                                          
 5                 6                   1  2                    3
____   (delay)    ______              ______              ______
    |____________|      |____________|      |____________|      |____
                         dwell period 

The ecm delays one reference pulse from the module in order to provide
advanced ignition timing. In a dizzy system, the mechanical rotor
controls which cylinder the spark travels to, so the ECM doesn't care
which cylinder it's on. It simply retards the pulse the required
amount of time, then sends it to the module.  You can see how the ecm
controls timing and dwell by controlling the delay between pulses. 
And yes, the distributor ECM is limited in how much dwell it can
provide at higher rpm, but it can optimize the time available.

Since your DIS reference pulses are timed equally low/high, you cannot
use your results to determine how the ecm handles the reference
pulses.

If the DIS cal. is inverting then delaying the pulses, you'll end up
decreasing dwell as rpm increases when you try to run it on the
distributor engine.  If you run the distributor cal. with DIS, all
timing numbers will be advanced, as they will be calculated from the
initial low pulse rather than from the end of the initial high.

What would help is finding a P4 dizzy engine to get readings from. 
There are several of these, after 93 in trucks and astro/s10 models. 
BTW, good idea using the recorder. 
Shannen



As it turns out the EST Signal is not inverse.  The timing is just off.  I
have managed to get the timing back in line with all zeros in the Ignition
Advance table (zero on the scanner, zero in the tables, and zero on the
dampner with the timing light)  But when I put values in the timing table,
they show up on the scanner but not on the dampener with the timing light.   I
believe that all I'll have to do is change the KMINRTD2 and KMAXRTD2 values
but that is when my second memcal failed so I didn't get a chance to try it.
I was also starting to think that maybe an advance on the table might lead to
an actual retard, but the more I think about it the less that makes any sense.
I'll just have to find out when I get this Memcal thing straightened up.

Ted

ALSO If you want me to, I can send you copies of my .wav files that represent
the EST Signals.  That way if you have sound editing software (or download
some shareware) you can see them for yourself.