[Diy_efi] Re: CNP source

[Kenny Bauman]

Hmmmm...

Much of this is correct from what I have seen.

Biggest difference that I see is that my info says
these coils are only "kinda" smart. They don't
actually control dwell, but limit it to 1/10 of a
second.

Dwell starts when the trigger signal goes high, when
the signal goes low the field collapses and you get a
spark.

Can someone confirm or otherwise give info on this
discrepancy?

Garfield has worked with these a good bit and probably
has the full info on this. Listening Garfield?

Thanks
Ken Bauman


--- "J. Creech" <jcreech1 at olemac.net> wrote:
> > I am doing a twin-plug conversion to my 911 Turbo.
>  Any good sources of
> > the latest GM CNP's, as above? Part number?  NAPA?
>  Thanks.
> >
> >
> >
> > Marc J. Reviel
> 
> -------------------------------------------
> I've saved a few emails from this and other lists
> over the last few years, this is what I
> could find about the GM latemodel CNP setups. I
> *thought* I had one saved with a current
> part # - but can't seem to find it in the irrational
> pile of effluvient I call "My
> Folders".
> 
> -Scott C.
> -------------------------------------------
> 
> This is cut from an email by Jurgen Hartwig:
> 
> Regarding the CNP, or rather Smartcoil, as it was
> called in 1998 archives,
> here are two pieces you and others might find
> interesting.  Both below
> quotes were written by Gar, I believe of EGOR fame.
> 
> "A guy in our Aviation group that
> works in a GM lab sent me one of these off a
> decommissioned test
> vehicle, and they are NOT mere IGN coils, they're
> complete single-coil
> IGN "systems". They contain ALL the electronics for
> dwell control,
> current limiting, etc etc. These coils are DIRECTLY
> run from the
> ECM/PCM. There is NO module. They have 4 terminals
> (plus the HV
> terminal, that uses these ratchet style terminals I
> was tellin bout
> yesterday), two for Bat Gnd, and Bat +12V, and the
> other two are the
> digital EST signal and it's low-noise gnd return.
> Not usable for ION as
> a transformer-type coil, cuz you cain't get to
> either the primary or
> secondary on these puppies, but still a VERY elegant
> setup, indeed.
> That ain't all. The biggest shock is yet to come.
> Brace yerself. They're
> actually CHEAP (and nice and light, too). I couldn't
> believe it when I
> went to check them out further. The GM parts counter
> LIST price is $41
> for each "smart coil", and EVEN the harness for
> tying four of them
> together is reasonable, list price of $62. You get 4
> connectors for the
> 4 coils, and another larger connector. Not a bad
> price for 4 GM
> connectors and pigtails (if you decided you couldn't
> use the harness as
> is), at the very least, and you might even be able
> to get the bigger
> connector from Packard! The shorty coil wires (yes,
> these DON'T squat
> ontop the coils) have them real nice connectors I
> mentioned, and they as
> well are pretty reasonable, at $11 ea list."
> 
> And
> 
> "I have nary a clue as to what an ICM is; never
> heard that before, unless
> you mean just a "module". But these coils have all
> the electronics in
> them to do the dwell compensation, etc., so they
> have NO module, but are
> fired directly by a 5V logic level signal coming
> from the PCM. There is
> NO separate system for just the IGN, the PCM
> controls all the IGN & EFI.
> As far as a retrofit, not without some additional
> electronics. You need
> at LEAST a crank wheel to fire these per-plug coils
> in pairs, and if you
> really wanna fire only one plug at a time, then you
> HAVE to have a cam
> reference as well. In addition to mere triggering,
> you'd need something
> to model an advance curve, both the certifugal part
> that's rpm
> dependent, and the vacuum part that's MAP dependent.
> Rather than an older style dizzy based retrofit, I'd
> say these new GM
> SmartCoils are more appropriate for someone who's
> gonna buy an
> aftermarket ECU that's cabable of outputing spark
> trigger signals
> directly, on a per-cyl basis. Then they'd be ideal,
> just one wire pair
> from ECU to coil per cylinder, and poof coil/module
> DI system a done
> deal."
> 
> Bob, I know these "Smartcoils" are available on the
> V8 Camaros.  You might
> be able to find these in a wrecking yard.  You can
> also wire the two
> triggers together, ala DIS.
> 
> -------------------------------------------
> 
> > That is correct.  Wolf dealers actually use them,
> and I can purchase them
> > for about $50-70 a pair.  This is my most cost
> effective route, and I'll
> > probably do it, since I know it has been done.  I
> saw the posts about the
> > "smartcoils" and thought this would be worth
> investigating.  If I read the
> > post correctly, Gar mentioned that you might/could
> use the single coils in
> > waste spark fashion by tying the triggers
> together???
> 
> Yes, still one coil per cylinder though.
> 
> I've run my car on these coils using a PIC based
> circuit to
> distribute the ignition signal to the individual
> coils.
> 
> Driving them is easy - raise the trigger signal over
> 2.7V then
> when you are ready to fire, ground the signal.   You
> have to
> be careful when you 'arm' them since they will fire
> after
> 1/10 second if you leave the trigger signal high
> that long.
> 
> -Orin.
> 
> -------------------------------------------
> 
> Andrew Theurer wrote:
> >
> > I'd look into the LS1.  I think they have the
> ignitor built into the coil
> > itself.  The jobber price may be around $35 each.
> 
> Yes, they are probably your best bet for a retrofit.
>  The true COP (LS1 coils are
> "coil near plug", i.e., they have a short wire)
> requires that you somehow support
> the coil appropriately out at the end of the plug,
> so the you'll need some weird
> bracketry.  The CNP allows you to bolt the coil to
> the head or the top of the valve
> cover or whatever is convenient.
> 
> -Eric Fahlgren
> 
> -------------------------------------------
> 
> At 02:42 AM 3/7/01 -0500, you wrote:
> > >Bob, sorry I don't have the info about the pin
> identification.
> > > Hopefully, someone can assist.
> 
> My 2000 Camaro shop manual shows the coil
> connections are:
> 
> A - Ground
> B - Reference low  (seems to be ground in the PCM,
> probably ground return
> for the "Control signal")
> C - Control signal
> D - 12V with ignition on.
> 
> The manual indicates that the coil is fired by
> grounding pin C.
> 
> I hope that helps.
> 
> -Ira Emus
> 
> 
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