Holley ECU Info

[Tom Cloud]

>Hi Tom,	
>Yes I would be interested in whatever you have so far.  I would still
>like to get it all down because I have a few ideas I would like to
>verify.  From a technicians point of view I would have to say that the
>fuel pump control is the proportion function of the controler, accel
>pump is derivative and idle,mid, and power circuit is the intergral. 
>Which would leave me to believe that this is where one would want a
>MAP.  The intergral portion of a control loop is normally used for
>compinsating for the rest of the affecting varaibles known or not. I can
>only receive text to my box.  I would really like to have those
>layouts.  When you say Gerber is that for downloading into a Gerber
>Signmaker? Writing rather broken today In a hurry 		
>
>
>				Thanks,	
>
>				Alan,

the Gerber function is to load a route pattern to a Gerber plotter
for making a PCB  --  my "layout" is really nothing more than
pads with overlaying lines shaped like components -- no traces,
so it's just a parts layout pattern.  But, it's on a Mac in Douglas
auto-route file format -- which means ??   I dunno, so I'm hoping
it won't be too big a PITA to convert to a JPG or GIF

as far as second-guessing the control functions of the unit, I
don't really follow your logic .... P, I, or PID control functions
don't necessarily have to be dedicated to specific inputs or
parts of the control loop.

I'll bet you that the controller is quite simple, with a derivative
function for the accel pump and rpm/tps relationship being some
weird function requiring the multiplier chip.  The rpm is probably
converted to DC and the required fuel computed from the TPS and
the dc level derived from the RPM.  (**note that "simple" can
be very obtuse and hard to define in an analog circuit  8^) ...
especially when non-linear relationships are required.)

Doubt that any of the circuits are integral, as that would require
feedback -- and there is none !!  the controller is open loop
at all times.  Integral compares a setpoint with the error and
continuously adds the difference to the correction signal, causing
the correction factor to increase until the error goes to zero.  If
you have no feedback, there can be no error signal.  All the ProJection
does, IMO, is take some inputs and outputs a set pulse width (I've
already confirmed this) to the injectors at a varying rate to control
the fuel flow -- no feedback, no error.  That's one of the problems
in controllers with no feedback -- they have no way of knowing
about changing conditions and can't compensate for them.  Having
the EGO feedback circuit would give some semblance of feedback, but
all it does, IMO, is modulate the TPS signal to keep the EGO voltage
above a certain minimum -- doesn't keep it from going over any
amount (i.e. it fixes the problem of the alpha-n controller where
it goes lean at part acceleration until the rpm catches up with
the new throttle position).

The fuel pump control is just a PWM signal to allow the pump to
run more slowly for low-rpm operation .... I'll wager that it's
a two-position function ... low and full on (actually, that's what
the manual or something I've read says).  Anyway, it's really not
part of the "control" circuit -- it's just a speed control for
the pump -- I'm not even using it as I have a relay supplying the
full 12 volts to my pump.

Tom Cloud

      Insanity is hereditary, you get it from your kids!