jwups0887

Any ideas or help would be great.

Purchased a 1966 Mustang with ignition wiring issues.

Initially:
The car wouldn't start unless a jumper was run from the battery to (+) on ignition coil, once started it would not shut off unless you took the (+) wire off of battery.

Previous owner did:
*New ignition coil.
*New ignition switch.
*New sarting relay solenoid.
*New battery (+) cable
*New starter in box, but he never put it in.

I am using the Ford wiring diagrams for a 1966 so I can figure out WTF is going on.

What I have found and done:
*The wiring harness to gauge feed on firewall the wires were all fused together. Replaced with new harness.
*I put a magnetic pick up in distributor instead of points, also installed the performance coil that came with kit. After testing, I didn't get any volts at coil, so looked into it further.
*Also put new starter relay solenoid.
*The wires on the neutral starter switch were all fused together, so replaced with new neaural safety switch.
*The solenoid to starter cable was all cracked with exposed wiring and figured it could be shorting out, so replaced with new.
*Inspected all the wires in behind the dash and inside the car and found no other wires fused together.
*Found he wired the ignition switch in wrong, because he did not connect the ballast resisitor on switch.
*Immediately when you connected the battery to the car, the starter would try and start the car even with out a key in the car. I have since fixed that, so it works the way it should.
*Everything else in the car electrically works fine.

Tests performed:
*Battery checks ok with voltmeter, plus I have been charging the more I use it to try to figure out the problem.
*Didn't get any volts at the coil with the ignition switch in the 'on' position.
*With the switch in the 'off' position, on the solenoid the only position that has volts is the (+) battery positive cable.
*With the switch in the 'on' position and with the starter connected to solenoid I don't get any volts at the coil, starter post on relay, and both the S + I posts on the relay.
*With the start cable at relay solenoid disconnected, and the ignition switch in the 'on' position I get full 12V at the coil.
*When I had the starter disconnected and my wife turning the key to the start position everything on the relay that should be getting 12V was getting 12V's.
*When I ran a jumper from the (+) battery cable on relay to the (I) post on the relay the coil registered 12V's.
*With the new starter in the box, I connected the (+) starter cable and ground the starter with a wire to the engine area, it had the same results as the old starter, nothing at the coil.
*After wiring in the ballast resistor in which the previous owner did not do correctly, the coild checks out fine with the volts being 12 and then when I ground the (-) post on the coil it lowers the volts comfirming the ballast resistor is functioning, but that is all with the starter cable not attached to relay solenoid.
*I have checked all the ground wires, and also ground the battery to the frame and the (-) negative cable on the battery is gounded on intake manifold.
*I also sanded down the inner fender wall where the starter relay is mounted to make sure that has a good ground.

What I need to figured out, is:
Why when the starter is connected there is no juice at the coil and why when I disconnect the starter cable there is juice at the iginition coil and everything is fine. I do not want to start the car up until I figure out the problem because I don't want to fry any more harnesses. I could jumper a wire from the battery to coil to get it started, but again don't want to damage any work that I have already done.

Any help or ideas would be great.

2+2GT

Put the ignition in the ON position. Using a test light or voltmeter, check power at the coil + terminal. Check that same wire at the plug on the firewall, both the wiring side and firewall side. Then check the pink wire under the dash at the firewall. Then check the pink wire at the connector near the ignition switch. Then check the pigtail at the switch. Sooner or later, you'll go from nothing to something. You should have maybe 7V at the coil, and by the time you pass the pink wire, 12V.

jwups0887

Thanks 2+2GT, I will check tomorrow. I did not check the wire from the coil on the inside of the firewall. One question, I have to look more under the dash tomorrow, to refresh my mind, but the previous owner did not wire the pink wire(resistor) into the ignition switch, which is what I did which when I checked the coil with out the starter hooked up it showed that I had a ballast resistor connected, which I didn't have that before.
Question is: the pink wire goes from the ignition switch and then looks like it heads to the fuse box. There is a real short wire about 1"-2" coming from the firewall, it has a red bullet style plug on it, it is light in color much like the resistor wire and I know it is the original wire. It has nothing plugged into it. There is a little cut out in the thick rubber foam firewall insulation which is where this wire sits, it is probably above and to the right of the gas pedal by about 6". Could that be a resistor wire? I just didn't see any loose wires hanging there in the area that would make sense to plug it in to it. When I tested the coil it did have resistance, the 12V dropped to like 6V or so.
I also have two wires that I have no idea where they go, they are orginal and I just happen to find them like maybe they fell from behind the dash. I couldn't locate what these wires were to from the wiring diagram. Wires in question:
Wire #1: Looks like it could be dark green or dark brown, it has yellow bullet connectors on it, one female and one male, probably about 15" long.
Wire #2: Looks also like dark green, I am thinking it is a ground wire. One side is a 90 degree angled connector much like the ones on the back of the dash bezel, the other connector is just a U connector with not insulating rubber at all, like it is a ground wire. Maybe 16"-17" long and it has a weatherproof rubber grommet on it like it went into the firewall.

Thanks so much for your time and advice.

2+2GT

The factory resistor wire was insulated with a rough pink material. Sounds like yours has been messed with. Ford didn't use ballast resistors. They also didn't use all the plugs.

Starfury

Unless the ignition is grounding the coil with the key in the 'on' position (which will cook your coil in short order), you should be getting 12V at the coil + terminal, not 7V. You won't get 7V until the coil - terminal is grounded through the ignition, creating a closed circuit where voltage will drop across resistance, namely the pink resistor wire. In an open circuit, all points connected to the supplied voltage will read at that supplied voltage, regardless of resistance in the system.

jwups0887

Hey Guys, Thanks for the input.

Yes there is no ballast resistor, my fault it is actually resistor wire. I just been natually calling it a ballast resister mainly because I installed one on a 67 cobra 427 kit car I built.

The car was actually professionally wired by Glasser Mustang Restorations in NJ, so most of the wires are new, but some are original.

I am getting real close to solving this, I was doing a lot of circuit testing wires inside the car when I smelled a electrical fire, so like a dummy I grabbed onto the main harness like I was choking a chicken and burned the hell out of my hand.

I did find the resistor wire, it has a rough sheathing on it and that was the wire that was not wired into the ignition. This "pro" who wired it wrapped it tightly with all the other wires than wound it with electrical tape, which I think is totally wrong because that resistor wire generates a lot of heat.

I am waiting for the harness to cool, then I have to cut all the wound electrical tape around it and see WTF is going on. I will separate the resistor wire and keep it from the other wires.

What I did find on the ignition, is when it is in the 'off' position only the yellow wire has juice, when the ignition is in 'on' position all wires have juice except for the red/blue stripe wire.

This should be interesting. Have a great day.

2+2GT

Seems like everyone does that, once. From then on, we hit the switch off, and back away slowly, as if from a rattlesnake.

MrMustangInc

We make the 66 ignition plug and pigtail wire behind the switch. If all else fails try replacing this section of wiring. It isn't expensive and is a lot of the times why the Mustang has ignition problems. You can call Mr. Mustang at 1-800-543-9195 Monday through Friday EST from 8:00-4:00 and we can ship it right out to you.