More HEI HEI

[peter paul fenske]

Hi Shannen

I presume you have the schematic of the 4 terminal..

Yes 12 volts will fire the P terminal..

My rig merely simulates the action of the pu coil in
a normal HEI. 

However you cannot pulldown the P terminal. 

I am an engineer not a mechanic. I do not directly put
12 volts on to explosive electronic devices . Hence the
680 ohms to feed. It may work fine without.

Now if you got the 4 terminal with a charging cap
the cap is in the N circuit. If you tickle the N
sufficiently I presume the cap will charge up totally
and swamp the circuit. Ie it will cease operation after
being tickled too much. 

And yes it will take a very low voltage to fire the circuit
IN differential mode. Remember I am trying to fire
this thing unbalanced. This means I must over
come the DC bias on the transistor as well as
provide the firing signal

Gm provides a lot of gnd switch outputs. OC means
open collector. The ref signal is not a gnd switch signal

later:peter

>  Not questioning what you did, only asking questions...  An
>old GM test is to connect a test light to battery + and touch
>it to the P terminal of the module.  If coil fires, module is
>supposedly ok.  This has worked for me whether or not the
>pickup coil is connected.  Also, for use in firing a remote
>coil I tied the N terminal of a module directly to the
>negative side of a coil on a running engine. I had nothing on
>the P terminal.  The module fired my remote coil every time
>the vehicle coil fired, until the engine reached about 1200
>RPM.
>
>I'm asking this:  were you providing a complete circuit for
>the signal?  P and N connected to the source?  I would think
>it would take very low voltage, .5 to .7V, to fire module this
>way as I believe that's all it takes from the pickup coil to
>trigger.  Why/how did you decide to put the 680 Ohm resistor
>in line?
>
>Just thought of something.  The EST line is a digital signal
>from the ECM.  If the module was powered on, 5V supplied to
>the bypass line, could the pickup coil terminals be completely
>bypassed by supplying a square wave on the EST line?
>
>Oh yeah, about heat.  If a module is replaced and dielectric
>grease isn't applied to the back before bolting it down, it
>usually lives a brief life.
>
>"The ref output to ecm was the same W.F. about 6 V in
>amplitude not O.C."
>WF=waveform
>OC=??
>
>Thanks.
>
>Shannen
>
>
>
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