Ignition coil resister wire

[1970FordTK]

As the topic states I'm looking to know what the sign/signals are that the ignition coil resister wire is going bad. Also, are there any pictures along with the tech stuff about replacing said wire. I aint the brightest bulb in the box, but I know if someone has delt with this before. Its just plain smarter to ask and get help than to butcher something and take twice the time and money doing it. Things like, how many volts should it be sending to the coil with just the switch on. What the omhs of resistance should be cold. What color wire shoud it be, and is it nessicary to run a resister wire. Does the resister wire run all the way from the switch to the coil and so on. Main reason I like pictures of the actual stuff is that wiring diagrams tend to be like a foreign language that I don't know to me. ( by the way woudn't be the first time my IQ was said to be the 40watt bulb too) Any and all info ya'll feel willing to share about this will be highly appreciated. Thanks in advance.

[Thunderfoot]

Sorry I don't have pictures
But to help with some of your questions.
The Resister wire is a PINK wire and it is inside the cab going from the ignition switch to the connector where it goes through the firewall. The wire that is in the engine compartment is normal wire.
It should be somewhere around 1.6 to 1.8 ohms
You should have 6-9 Volts at the coil.
You need the resister wire or a Ballast Resistor in the circuit. It does a few things, but main one is makes the points live longer and the coil run cooler as it (stock) is not designed for continuous 12+ Volts.

Hope this helps...

[1970FordTK]

Thanks for all the info, it will defiantly help. One other quick question, how long is this wire.

[Thunderfoot]

I've never pulled one out myself... but I think it is about 2-3 feet long. You can get replacement wires at the parts stores or you can run regular wire and use a Ballast Resistor...
Here is the resistive wire from parts america... http://www.partsamerica.com/productdeta ... 05&PTSet=A

I just remembered that you’re probably working on a 70 right? If so the resistive wire part may start just a bit down from the ignition switch, but it should be easy to find by the pink color... Check out this diagram http://www.fordification.com/images/sch ... rging2.jpg it is for the 69 but should be the same for your 70. Look at wire number 16 from the ignition switch and you will see where it has a small connector and turns into wire 16A. This 16A is the pink color resistive wire.

You were also asking about signs of it going bad.
It would usually be good or bad (work or not) but it may start getting more resistance then it is supposed to just before it opens up. This would lead to less then the 6-9 volts at the coil.

What kind of symptoms you having that you think it might be this wire?

[1970FordTK]

On occasion the truck cuts off, turn the key to restart and in less than half a cyclinder turn it starts back up. I've gone days without this happening and had it do it twice in a 3 mile trip. Then two days without it again, then boom it does it again. Its so dang random that I fully am begining to believe a gremlin is in it just doing it to torture me. I eleminated the carb by running it on another motor without the first problem over 280 miles. I've double and triple check my grounds and connections. And thanks to you I have fully checked all the wires that have anything to do with the ignition system. Unless both volt meters I have are faulty, everything is within specs. Both before and after the truck is warmed up. The only thing other than the entire wiring harness left to replace is the ignition coil resister wire. Thats why I inquired about signs/signals it may be going bad. Any body got a sure fire way to kill gremlins?

BTW, thanks for the info and willingness to help Thunderfoot.

[Thunderfoot]

Always glad to help.

Sounds like you checked all the wire connections like the +/- wires on the coil and your grounds.
What you have going on could be one of these things...

Could be the ignition switch itself is going bad and intermittently makes bad contact and shuts the motor off.

The wire from the (-) of the coil to the distributor could have an intermittent short or brake in it. Also, be sure the condenser has good connection in the distributor. Ohm out the wire between the distributor and the points and move it around and see if it changes...

Also, check the wire for the boost start from the starter solenoid to the coil. This could be the starter solenoid (have seen it on a couple) causing the problem. You could unplug the little brown wire from the solenoid (one closest to the firewall) and see it that helps. This wire is used to help with cold starts as it puts a full 12V to the coil when starting, then after you stop cranking it drops back to the normal 6-9 volts. Make sure the wire doesn't get grounded out or it will not let the motor run.

Those are the 3 things I can think of that are kind of common for electrical running problem like you have.

Let us know how those go or if you find something else.

[MIL1ION]

This is from a 75 but it should look like this.

[dcbullet]

Could be the ignition switch itself is going bad and intermittently makes bad contact and shuts the motor off.

I would definitely investigate this possibility. My truck had that problem. Basically the ignition switch was very loose and when you would hit a bump, the engine would just shut off sometimes.

A new ignition switch solved the problem.

[1970FordTK]

Roger that, My ignition switch is six months old. But at this point I'm not going to take any item as too good. Thanks for the pictures MIL1TON, they will help out if running down the other ideas Thunderfoot gave me don't work. I'll let ya'll know what I find, thanks for the info.

[1970FordTK]

After checking out all the wires, I decided to double check the internals of the dis. like Thunderfoot suggested. I got lucky while in there and pulled on the points a little, this is what I found. The porcelain/plastic part of the points was cracked and the stop nut was lose. I have replaced the points with a decent quality set and so far all the trouble has stopped. Big thanks to all ya'll who have stopped in and offered up suggestions to help out.