Duraspark II, or HEI conversion questions.....

bronco2fan said:

AC, Alt, Gauges, Blower motor, wipers etc. Anything for the ECU can go. I can't remember if I cut anything or if it just went away with the harness. To be safe, if you have to cut it, make sure you leave enough to splice back in if you have to. Better safe then sorry.

Sorry no wiring diagram here.


If you move the stuff off the fender well and take another pic we may be more helpful

Click to expand...

Yeah i figured anything that goes to the ECU. I found that the Alternator regulator wires plug into a mutual plug with the ECM harness......seems like something im gonna hafta cut or thin out the harness on the other side also and just go down to whatever type of plug i can find male and female for, to accomodate the wires i need and get rid of the rest of the previously computer controlled wiring.

For now i may just cut the wires except the alternator regulator (unless there is something else i will need) and plug it back in.

Ill do a better picture of what i got going on tomorrow. The stuff on the fender is a fender cover and a towel. Haha.

All the chassis and alternator wiring is independent you will see once you remove the wires from the protected sheath. The less wires you cut the less you need to repair. Basically the only wires you need to cut are hot to the computer and i believe the other is a ground wire. I then used a section of the sheath to put the used wires in to mae it pretty.

OK, so, got the wiring harness out. I kind of realized what you guys were saying, in a sense, and i think i have achieved what i need here....so after unwrapping the harness, i am left with 6 wires in the plug that goes to the gray box plug near the firewall, where the Alt Reg wires meet. Then also i snipped the choke heater wire out of the main harness, so i can use that to wire up electric choke.

The plug:


Wire for the coil (going to get a new connector, mine is not worth saving.)....the green wire went to the TFI module and will go to the HEI replacement. This wire was spliced with some yellowish wires including the yellowish wire from the coil.


Then i also have the two wires (orange/lt blue, and white/black) that come from the alternator, into the grey block plug, inside the truck, and end up back out at the Alt Reg. (Assuming they go to the gauge and/or fuse block and back out into the engine bay to the reg?)


I have the red/white wire that goes to the coolant temp sensor/sender:


And lastly, there are two other wires....a red one, and a white/red one. The red one has a plug and i think it honestly went to an emissions piece so i may cannibalize it for something else if it is a keyed source. The white/red goes straight to the computer and was butt connected to a beige wire so i really dont know if it was supposed to be that way or not, but i went ahead and yanked it out of the butt connector anyway since he was guilty by association with the computer.... Im assuming this is a keyed source or a reference wire of some sort?




And then of course i have the choke heater wire snipped. I plan on possibly wiring this into a 3 wire oil pressure switch setup, so the choke is only running when the truck has oil pressure. The oil pressure sensor wire on this truck is worn in half anyway.

Am i missing anything or is this pretty much what you get? This truck doesnt have AC from the factory and frankly, i dont want it.

Also, the terminals in the grey block plug are pretty loose. I am considering changing the plugs, so they have good connections.

So far so good. Just take your time and if you have a doubt, leave it for later and follow the wire. I didn't do HEI, so really can't say much there. I used the harness from a 70's era duraspark that was plug and play.

Thank you all! This has been much helpful.