EST observations (kinda long)

[Ludis Langens]

Tedscj at aol.com wrote:
> 
> >  The problem is that the other edge may "move around" at different RPMs.
> 
> Based on what I recorded (the signal going from the Module to the ECM), it
> does not seem to move around at all.

It has been reported that in distributor systems the "wrong" edge does
move around depending on RPM.  That edge depends upon the leading (or
trailing?) voltage slope from the pickup coil.  And further, the
reference pulse is short - nowhere near the 50% duty cycle you observed
on your DIS engine.

> As for the EST signal that goes from the ECM to the Module... 
> If THIS signal is inverted, then it would be
> fairly difficult to get a DIS module working with a Distributor typ .bin

It would be difficult for that signal to be inverted - it is a
multi-directional signal with open collector drivers at both ends and a
resistor pullup.  I would think it difficult for the ECM to have the
same amount of diagnostic checking (code 42) if the sense of the signal
is flipped.

> SyTy and Sunbirds use a dirtributor.  I would like to adapt DIS to work with
> their .bins.

I checked a known DIS program.  It had _exactly_ the same dwell
computation, with all the same constants.


Bruce Plecan wrote:
> Is there something in what you just printed that would invert the EST line,
> by changing it?
> Er, is this just the dwell end of things, or did I just miss the point?..

This was just the dwell computation end of things.


Two possible places where a DIS vs. distributor switch might be located:

  Any byte sent out a P4's SPI port while bit %00000100 in location
  $4002 is set.

  The configuration word programmed into the TPU at location $3FFC.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/