Falcopilot

I am finishing up me EFI 5.0 swap into my '68 and I'm down to the part I've dreaded since day one...........WIRING. I generally do not have a clue.

So.


Pardon my ignorance but if I need switched power which wire do I access on the ignition switch? Is it the red wire with the blue stripe? 32 in the schematic?

I installed an electric fuel pump running through an inertia switch and am wiring the relay. I already have it wired to power, spliced into the wire from pin 22 in the harness, and the inertia switch wired to it.......I just need to connect it to switch ON power.

Sorry if this is over simple to you guys, but still trying to learn here.

Thanks in advance for any assistance.

fastbackford351

Put a 12v test light on the switch terminals and see which one lights it up when you turn the key to the "on" position.

Falcopilot

Thanks Fastback. There is no power in the car yet. That's why I was hoping someone could steer me toward the correct colored wire.

fastbackford351

I don't know about the colors but if you don't have power then if you have one you could use a continuity tester on a multimeter instead of the test light. Same deal, turn the key to the "on" position and see which one rings.

Falcopilot

Cool, thanks!

67mustang302

Ignore the colors and go with what a voltmeter tells you (someone could have monkied with wiring so color means nothing then).

If you're wiring EFI, ECU power comes directly off the battery, relay power for things like injectors, lights, fuel pump etc should come off a power distribution block tapped from the starter relay, or off the starter relay. Don't wire anything other than the ECU directly to the battery or you'll get EMI.

Don't pull power through relays from a hot wire somewhere in the car, or from the factory fuse block etc. Factory wiring from the 60's was ****ty and can't carry the load of modern electrical crap, and the whole point of using a relay is to pull directly from the power source itself (not some obscure wire coming from the power source).

Starfury

+1

Really, I'd recommend adding a fused distribution block and relay(s) for the EFI system, and maybe another relay for the headlights while you're playing with the wiring. You want to make sure you have good circuit protection and isolated power sources for your fuel pump, ECM, etc.


Btw, that I believe that red/blue wire is the dash lights. Not exactly a high-amp power source.

67mustang302

Basically, all the ECU power comes directly off the battery (using relays where appropriate, such as fuel injectors), everything else comes of distribution block. Always use fuses or breakers or both for power circuits.

tx65coupe

I added an auxiliary fused distribution block with a relay for everything non stock on the car. It has two banks if I remember right. Once side is switched power and one side is constant power. I also added headlight relays.