Switched Ignition Source

daustin

Veteran Member
Jul 29, 2009
262
Woodstock, GA
HEI cars are different. No ballast either. Liks the OP's 77. I guess that change was mid-74 as HEI was introduced.
I've got a 76, factory HEI. On that car there is no ballast resistor or IGN resistant wire. But the "start" power works the same way. IGN for running, starter jump for starter. Later years may work differently.
 

autobahn

Member
Jun 8, 2005
60
55963
you WILL find that the male spade ign in the center of the fuse block will NOT have voltage when cranking I just went thru this, Sniper doesn't pull very much juice so just about any pink under the dash or suggested above off your HEI ,ALSO very important your main power MUST come off the battery the only way you can protect the system from surges
 

Jim Streib

https://www.flickr.com/photos/[email protected]/albums
Apr 6, 2004
574
Saint Louis, MO USA
What we all need to watch is some circuits are not protected by fuses in the fuse block. For example the HEI wire on the distributor on most cars (and even the resistance wire on most of the old style points systems). This is why I like using the spots in the fuse block as normally these are fused IF you choose the proper spots.

I looked at the diagram on this site for the 76 model and the HEI wire is a 12 gauge pink that connects to the ignition switch and then the ignition switch connects to a 12 gauge red that then back under the hood, this 12 gauge red is protected by a 16 gauge fusible link. If a fusible link does open up, it's a lot harder to repair than a blown fuse.

Jim
 

Jim Streib

https://www.flickr.com/photos/[email protected]/albums
Apr 6, 2004
574
Saint Louis, MO USA
you WILL find that the male spade ign in the center of the fuse block will NOT have voltage when cranking I just went thru this, Sniper doesn't pull very much juice so just about any pink under the dash or suggested above off your HEI ,ALSO very important your main power MUST come off the battery the only way you can protect the system from surges

Out of curiosity, what vehicle was this in ?. I know sometimes there are one year changes that do not always show up on diagrams and this is why I'm asking ?.

I too have been taught that some things need to wired directly to the battery (power AND ground sometimes) as these companies making things cannot always see or know how well the existing wiring is in a vehicle.

Jim
 

BonzoHansen

Administrator
Lifetime Gold Member
Jun 1, 2005
21,424
Scott from Hamilton, NJ
Use the pink wire to trigger relays. Then you can run clean battery power to your efi. There is zero reason to touch the fuse box or run wires through the firewall. It's easier and cleaner.
 

Spellbound

Veteran Member
Oct 5, 2013
338
New Hampshire
The pink HEI lead under the hood is hot in run & start. You could use that to trigger all the relays you need

I used the HEI Bat wire as I believe was suggested (note if this is supposed to be a fusible linked wire mine may be removed if it matters) and it works well so far. No relay necessary - Sniper is a low current wire 18 or 20awg pink wire.
 




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