[Gmecm] Key-On Power for 7730

[Clair Davis]

Cutting and pasting from DIYEFI... I don't think Rick will mind:

This, folks, appears to be true here, too.  I basically made a little test
light circuit to see if there was an obvious break in the circuit between
IGN-1 and IGN-2.  Using an 1187 dash light, I wired I1 and I2 (and ACC just
for fun) together with a 9V battery.  I could not see any dimming of the
bulb between run and start, regardless of how fast or slow I turned the key.

Turning the key was the big problem, as I had to disassemble the dang lock
tumbler to make the motion consistent.  Kind of hated to do that, as 1969
ignition cylinders are unique (last year for dash-mounting for Mopar) but
I've got NO idea where the key for that sucker is.  Not much of a
theft-deterrent at this point.

Thanks, Rick, Tom, Tim, Terry, Will, and Lee for all the guidance.  Maybe
I'll finally get these last two wires done this weekend!

Clair


----- Original Message ----- 
From: "Rick McLeod" <dunvegan at sbcglobal.net>
To: <diy_efi at diy-efi.org>
Sent: Thursday, September 28, 2006 12:39 PM
Subject: Re: [Diy_efi] Key-On Power for 7730


> Good advise, but every ignition I've ever seen though has been MBB, not
BBM. (Make Before Break vs. Break Before Make)
>
>
----- Original Message ----- 
From: "Rick McLeod" <dunvegan at sbcglobal.net>
To: <gmecm at diy-efi.org>
Sent: Thursday, September 28, 2006 8:37 AM
Subject: Re: [Gmecm] Key-On Power for 7730


> Ign1 ------|>|------|
>                          |-------------- to 'Key-On' circuits
> Ign2 ------|>|------|
>
> Use 5Amp 100PIV diodes for the above, it will privide +12V (sans .7V for
forward diode, which is insignificant) to the circuits that require power
when cranking and running. I've done this many times, KISS is your friend!
>
> Hit your local RadioShack:
>
>
>
> 6A, 50V Rectifier Diodes (4-Pack)
>
> Model: 276-1661  |  Catalog #: 276-1661
>
> $2.49 for the package
>
> ----- Original Message ----
> From: Clair Davis <clair.davis at charter.net>
> To: For discussion of GM EFI hardware and software <gmecm at diy-efi.org>
> Sent: Wednesday, September 27, 2006 9:42:03 PM
> Subject: [Gmecm] Key-On Power for 7730
>
>
> Background... I've got a 69 Plymouth Valiant I'm multipoint-injecting with
a
> 7730 box.  I've got two wires left to run, and one of them is killin' me:
> Key On Power.
>
> On my old Plymouth, the ignition switch has 5 wires: BATT, START, ACC,
> IGN-1, and IGN-2.  IGN-1 is the "run" power to the coil, dropped down with
a
> ballast resistor to keep the coil happy.  IGN-2 is 12V straight to the
coil
> for hotter sparks while cranking.
>
> The IGN-1 circuit is DEFINITELY dead while cranking, and IGN-2 is ONLY hot
> while cranking.  Once the engine fires, you let up on the key, the switch
> rolls back to IGN-1 and you go on about your way.  Problem is, I can't
tell
> how long the dead skip is in the transition between the two circuits.
>
> Is this a problem?  Seems like it might be, as the "key on" signal seems
to
> be the trigger for the whole start-up routine with the ECM.  Is a GM
> ignition switch one where there is no break in the power from "run" to
> "start" and back, or am I overthinking things?  Mopar guys that run MSD
> ignitions splice IGN-1 and IGN-2 together for the MSD to work, but that's
> hardly the same animal.
>
> Thanks in advance!
>
> Clair
>
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