[Diy_efi] Key-On Power for 7730

[Rick McLeod]

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:
Hit your local RadioShack:
6A 50V Rectifier 4pack
276-1661 for $2.49 per package



----- Original Message ----
From: Clair Davis <clair.davis at charter.net>
To: diy_efi <diy_efi at diy-efi.org>
Sent: Wednesday, September 27, 2006 9:40:41 PM
Subject: [Diy_efi] 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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