flip flops to drive ignition

[Bob Wooten]

Joe,

thanks for the information.  i did not find a copy of the flip flop
circuit.  do you have one?  if not, no biggie.  I think that mine is going
to have to be quite a bit different anyway.  I have to drive more than 2
coils (@ least 4 maybe 8), so.........  a few different issues.  I only
have one reluctor as well, so again different issues.  I think that i have
it fingered out, just the small details to work out.  anyone have any idea
of an application or part number for an easy (read simple) hall effect
sensor is?  i am looking for something like the after market ones
(adjustable screw mounting, put power to one side, ground to the other &
read the 3rd.  i down loaded a print of a GN ECM & harness & that has both
a cam & crank Pos sensors in it & they both look to be hall effect.  any
idea how they mount?  having not actually poked about under a GN hood, just
don't know.

thanks guys.
BW


> [Original Message]
> From: Joseph Obernberger <joelori at earthlink.net>
> To: <diy_efi at diy-efi.org>
> Date: 1/16/01 4:45:08 AM
> Subject: Re: flip flops to drive ignition
>
> 
> 
> Chris Conlon wrote:
> 
> > At 04:28 PM 1/15/01 +0800, Dan Zorde wrote:
> >
> > >How about using the ignition outputs to drive a couple of Flip Flops,
then
> > >you could tie opposite cylinders to the Q and Q(not) outputs, thus
every
> > >time the ignition driver fires it toggles the FF to alternatively
drive the
> > >coils.  You'd just need to figure out some way to overcome this 1/10
sec
> > >auto fire Orin was talking about.
> >
> > A friend of mine has a system that works along these lines.
> 
> That would be me!
> :-)
> It basically works along those lines - but you need to have some sort
> of reset for the FF.  In my case there are two position sensors on the
> distributor - when either of these sensors (OR) tripped, it would
> reset the FF.  The normal ignition signal that would normally go
> to the ignitor was used for the clock input.
> <http://josepho.www4.50megs.com/ignition_project.html>
> 
> > The stock Toyota ignition driver runs off a logic level signal, +5
> > to charge the coil, drop to 0v to fire. I *think* at one point he
> > was using 3rd gen RX-7 coil packs, which are apparently waste fire
> > but with the same type of drive signal. Supposedly they have a
> > pretty hot spark too.
> 
> Yes - it was using RX-7 twin tower (leading edge) coils.  They seemed
> to be happy with long duration pulses - stayed cool to the touch even.
> 
> >
> > Another issue he ran into at one point was conditioning the reluctor
> > signals. This caused some hassles. Also since the reluctors were still
> > needed by the stock ECU, it was important that the circuit didn't
> > interfere with that operation. 2 parts that may be helpful: the LM1815
> > (Nat Semi), which is an IC designed to deal with reluctor signals, and
> > MSD's p/n 8209 ignition stabilizer, which is probably not much more
> > than an LM1815 in a box, with a digital output.
> 
> I need to check those out!  Since it got cold, the signal conditioning
> portion of the circuit doesn't work very well to condition those
> reluctor signals and I get an occassional miss.  Perhaps I should awaken
the
> project again.
> Thanks Chris!
>                                                 joeo
> 
> 
>
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--- Bob Wooten
--- r71chevy at earthlink.net
--- www.r71camaro.homestead.com 


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