Ref. Signal off of AMC I6

[Shannen Durphey]

> 
> Date: Sun, 5 Dec 1999 00:56:23 -0500 (EST)
> From: Mike Comai <comai at expert.cc.purdue.edu>
> Subject: Ref. Signal off of AMC I6
> 
> I am currently trying to get my first major retrofit up and running.  I
> have everything installed and when I try to start it the injector's don't
> fire.  I was told that I need a filter on the negative side of the coil
> and to feed the filtered signal into the Reference line on the ECM (which
> I am using a '747).  I was given a design for a filter which looks like
> this:
>                5K               10K
> Coil    -----/\/\/\/---------/\/\/\/\------------ ECM
>                         |               |
>                       -----           -----
>                       ----- 15uf      -----100pf
>                         |               |
>                        gnd             gnd
> 

>From a mechanic's point of view, (and because there's little other
info to work with) why haven't you adapted a GM ignition module to the
AMC dizzy?  The voltage on the negative side of the coil "bounces"
after the plug fires, and your ecm may be getting what it thinks are
several reference pulses when it should get one.  'Course this is a
rough guess.... you might try to get a scan tool and watch rpm
readings during cranking to verify this.  Another possibility is that
everything is ok but your calibration is wrong, or your injectors are
wrong, or the coil isn't firing because the reference line is
grounding out the signal from the dizzy.

Also, if you're running the reference line from the distributor, do
you have the est line connected?  Where?  One of the great benefits of
using an ecm is computer controlled spark.  Without it, you're not
realizing the full potential of your project.
Shannen

> When the filter is in place, the injector don't fire.  When I remove the
> filter and connect the coil directly to the ecm it appears to flood out
> the engine :( If someone could explain what voltages levels and shapes are
> present on the neg. side of the coil and what it needs to get conditioned
> to for the ECM that would be great too.  Appreciate any help yall could
> give.
> 
> Mike Comai
> '79 CJ5
> 
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