12V switched wire for Sniper EFI

[superwrench]

Just finishing installing this Holley Sniper kit on a 340 '72 Challenger. All is hooked up except the 12 volt wire to power it from the ignition switch. Is there anyone who has made this swap to EFI and if so, what wire did you use to tie into??

[Chryco Psycho]

At the ballast resister you will find a blue 12v feed wire & a brown wire , you need to connect both to the EFI power wire so it has power while running & power while cranking [brown ]

[superwrench]

I was thinking the connections could be made under the dash in the harness somewhere.  Thanks for the tip !

[1 Wild R/T]

For the most part I agree with  Chryco Psycho, however there are possible problems... What ignition are you running?  When you connect the brown & blue you effectively bypass the resistor, some ignitions are fine with that, some fail...  If you run an electronic ignition & a coil designed for use with out a ballast like this one...  https://www.summitracing.com/parts/msd-8222/overview/   then connecting the brown & blue is a good choice....

[Chryco Psycho]

The same connections can be made at the base of the steering column you can use a diode inline if backfeeding the ign is a problem

[Katfish]

I had this issue to overcome with I installed my Fitech, solution was to tie the brown and blue together with a diode and use that to power the EFI.
You get 12V during crank and start and maintain separation for the ballast.

[RCman]

At the ballast resister you will find a blue 12v feed wire & a brown wire , you need to connect both to the EFI power wire so it has power while running & power while cranking [brown ]

This is what I did when I installed my Sniper setup. More details in this thread: https://forum.e-bodies.org/engine-transmission-and-rear-end/4/efi-fitech/1959/msg51959#msg51959

[superwrench]

MSD 8202 Blaster coil and using Chrysler Electronic system. Should be good to go doing what Chryco suggested.

[7212Mopar]

There are two spare accessory terminals at the fuse box by the steering column. One is switch and one is batt. Can the switch terminal be used? I read from other post that the 12v switch wire is just for signaling the control module. The EFI power comes from the battery.

[superwrench]

I tested that one for the accessory...it looses power when the key is in the start position. The battery one is 12V all the time. Would have been so nice to use that spade!!LOL

[superwrench]

Well....bridging the ballast succeeded in burning out the ECU.....guess it doesn't like 12 continuously. I installed a relay using the starter relay trigger (yellow) wire and connecting the output wire to a piggy-back terminal on the blue wire at the ballast. That way I get 12v when cranking, then it switches off when the key is released and defaults to the 12v key-on. Installed my spare FBO ecu and it fired right up.     I am going to try to source a diode.

[Chryco Psycho]

The ECU is always run on 12v continuous , I assume it was a 4 pin ECU , possible the coil load is what it didn't like

[superwrench]

The coil WAS smokin' hot....you're probably correct.