[Diy_efi] Key-On Power for 7730

[Tom Visel]

Mebbe it was just a crappy old switch.  Something he was in love with 
and the parts stores couldn't match, in any case.  I had to keep it when 
I did the FI conversion, and ended up using a relay, diode, and cap to 
keep it powered up.  Lots of fun - odd fire V6, MSD crank trigger to run 
the FI, original-style distributor for spark.  TBI feeding an early GN 
carbed-turbo setup.  Customer with more money than sense decided this 
was the hot setup for his rock crawler CJ5.  I don't pick 'em, I just 
fix 'em.
TomV

Rick McLeod wrote:

>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: Tom Visel <five10man at commspeed.net>
>To: diy_efi at diy-efi.org
>Sent: Thursday, September 28, 2006 10:50:54 AM
>Subject: Re: [Diy_efi] Key-On Power for 7730
>
>
>Use a cap in parallel with the diodes if there's a dead spot between ign 
>1 and ign 2.  Customer had a Jeep with a weird switch that dropped out 
>just long enough to make everything hiccup, and the diodes / cap were 
>the fix.  It may keep your power on a touch longer than the key is on, 
>but it hasn't been a problem on this project at least.
>
>Rick McLeod wrote:
>
>  
>
>>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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>>
>> 
>>
>>    
>>
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