So close, can only be 1 wire off from running!

[Banjo]

I'm getting excited, after putting a roller cam motor in 68 SWB, I have it close to running, but need your suggestion. It'll crank and run with the ignition switch held in the start position. When I release it and the switch returns to "run" position, the truck dies. So, I'm losing voltage somewhere. When converting from points distributor to factory duraspark stuff, I must have missing hooking up 1 wire somehow. I ran the red wire off the duraspark to the red/green off the coil and also wired in another thick brown wire that runs into the firewall and to the ignition switch. I ran the white wire off the duraspark to the "s" terminal on the starter solinoid. I'm just not real good at wiring, but I feel I'm only 1 wire off from running and solicit your help. Is there a ballast resistor I was supposed to have removed (I don't even know what it looks like or where it is) or what am I doing wrong? I really thank you guys for your advice and help (in advance)....I appreciate you. The old banjo.

[fordman]

i don't really know but the run circut seems incomplete.

[montana_hiboy]

If you don't already have the wiring diagram this may help....http://users3.ev1.net/~bmarr/57bcfe50.png

[Banjo]

Montana, I had that picture, but due to limited space under the dash and herniated disc, I wasn't able to stay under there long to try to figure out hooking the wires in that way, so I hooked the red wire to the red/green on the + side of coil and the white wire (these are the wires on the duraspark ignition control box) to the "s" terminal of starter solenoid. I was able to do that without enduring back pain.
I have been searching and reading, and someone has messed with this truck in the past, there is no thick pink wire I keep reading about. And, now, I'm reading about some kinda "resistance" coil, which I didn't know existed. I know the prior motor, that was running, but tore up, was an '83 Mustang GT 302, and someone had wired it for a points style distributor.
I have inserted a 90 Lincoln 5.0 (rollercam) and using a '85 Mustang GT distributor with steel distibutor gear and plugging that into the factory duraspark connector. I can only be one wire off, because as I mentioned, if I hold the key in "start" position, it'll run until I turn loose and the key falls back to "run" position and obviously voltage is gone (or drops) and truck dies. ??? the old banjo.

[Banjo]

sorry, my train of thought got derailed on typing that last one (happens often)....where I was going with the "resistance" coil...is, how would I know if I have one, and maybe that is my problem, maybe I'm trying to use the wrong coil? I have 2 normal looking coils laying around, one that was on the truck when it was running points, one that's off a stock 78 or 79 truck with a 302....and one that is off the 90 Lincoln towncar I took the motor out of, but it's not a "normal" looking coil, it's a little small squareish looking deal that I figured isn't compatible with older system.
I can't be but one wire off (somehow), but from looking, someone has monkeyed with the wiring some in the past to insert the prior motor. so I'm just lost, but I admit, I'm not smart about wiring and do admit a problem even with reading wiring schematics. I truly appreciate everyone reading and helping with my foolishness, I need to get this 68 F-100 running so I can figure out how to fix the heat in my newer F150. I figure when I start in on it, I'll break something, so I need a running backup. Banjo.

[fordman]

the only pink wire i have ever seen on these trucks comes from the cab in a group of three wires from the center of the firewall. i think it goes to the dist. but i can't remember for sure on that. it also wasnt a large wire that i remember seeing either. it is a small wire. maybe a 16 or 18 gauge wire.

[bluef250]

You probably need the ballast resistor between the red wire and coil.

[rjewkes]

wondering if the control bax has 12v + at all times or atleast during run.

[ladz]

switch the brown wire to the pink wire on the ign. switch Keith just posted a link on testing your ing. switch that will get r gone!!!! you have to find the wire with continuity in the on position and the wire that drops out when you turn to the start position .

[Wolf0r]

Yes what Ladz said. You have to run a wire from the R to your box. The other to 12v ign. This is assuming you are using the "blue" box. If it starts and then dies swap those two wires.

Also those who run a holley with the electric choke, you can run your B+ wire to the choke from the "sta" on the alternator the one with the black insulator. It's about 8volts. I am using a factory 85 5.8 HO holley and it purrs like a kitten.