For those of you running aftermarket harnesses where are you pulling a keyed 12v source from? My PSI LSX harness is wired and I have retained the power leads from the C100 to supply power to the starter solenoid, fuse box, and non fused junction box. My idea was to take the pink (C100 F4) which is for the ignition timing (TBI coil lead), and route it to my 12v key on junction. I'd like all my 12v keyed on triggers (vintage air, NOS RPM switch, aftermarket gages, etc) to run off this (its maybe a 14ga wire) but wasn't sure what everyone else is doing. I am a novice when it comes to advanced automotive circuits and figured i'd humble myself to the TGO community. I have a decent understanding of everything but struggle to identify the different circuits in our cars that are "key on" and "key on start".

Notes:

• 1990 TBI T5 car.
• All engine circuits have been de-pinned and removed from C100.
• C100 locations A4, and G5 have been wired from C100 to battery junction. (commons for fuse and ignition distributions).
• B4 running from C100 to starter solenoid.
• Running aftermarket gauges independent of OEM wiring (need to wire these to 12v key on)

 

If this helps. I'm grabbing a 12 volt ignition while cranking circuit to supply my ignition hot wires on my stock harness I reworked for coils, injectors, pcm,trans,maf,and o2s. I plan on using same or similar circuit for my aftermarket gauge lighting..

It's the second row , first left circuit. My car is 86 base Camaro that had a fi multiport 2.8. Picture is attached

 

Interesting. I think i am on the right track. My harness will power itself through the starter connections, and i think using the OEM ignition coil lead to power my 12v key on junction will work.

 

It's been a few years, but I "think" that's the wire I used for my Holley EFI. I'd check for ya, but.....don't have the car anymore.

 

Cool. I plan on testing all circuits with the engine harness disconnected to confirm my plan. There isnt a clear answer for key on power but i figure power to the coil must be constant and "on" during cranking. I did tie my fusible links to my main battery junction which the starter will be connected to. Should serve the same purpose as directly connecting to the starter.

 

Yes, for those coil, injector,etc wires you have to connect to an ignition hot on start wire or it will not crank.. ask me how I found out...

I ran a distribution block from the battery and added a 40amp 12v circuit breaker and battery wire for my auxiliary fuse block I bought, and the other battery wire goes to 140 amp 12v circuit breaker and wire to alternator..

The 12 volt hot while start is connected to axillary fuseblock for the harness ignition, and ground coming off battery...

This way everything except grounds are behind a circuit breaker and on fused on separate circuits..

as are the fan wiring


Pic below



All connections are soldered



edit: Excuse the wiring, it's a rough installation

 

Im feeling better about this. I truly appreciate the replies gentlemen.

Are you connecting this aux fuse panel to the C100?

 

Hey, Shifty. I started to write a reply but there's a lot to say and we just need to talk. PM me your phone number and I'll call.

 

I have a stand alone harness. I made a 4 circuit fuseblock just for the harness itself, and I have another isolated fuseblock that powers the standalone harness, my fans, and any aftermarket accessories, i.e. gauges

 

I got rid of the fusible links and no longer use the starter as a junction block. The distribution block shown has one post for battery, one for the alternator, one feeds the 3 maxi fuses and the last feeds the starter. Maxi fuses feed new under hood fuse block and the other two feed the stock fuse block and two additional blocks with 6 fuses each

 

There are also spare ign and batt spots on the front and back of the factory fuse block

 

Whoa whoa, back up.... I want to see the rest of that engine bay.

 

If you are ever passing thru Eldridge I’ll show you my taillights 😉. Don’t want to hyjack This thread

 

Then go ahead and post in your old build thread. Many of us would enjoy seeing what you did. I'd like to see your Maggie install and how you laid things out. It's not often we see something like that at this site.

 

Agreed. 418 LS3 with whipple? Car **** at its finest.