Vintage Mustang Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
159 Posts
Discussion Starter #1
After fighting for the last week to track down a short, I finally found it late last night. This a.m. I started the car and it ran great, but for some reason with the key in the off position power stayed on (the car even kept running until I closed the choke plate)to the coil and I came back to the car 10 minutes later to find the coil exploded. Thinking it was the ignition switch I went to my local used parts guy (if you need any used mustang part he probably has it)and got another coil and a replacement ignition switch. Tonight the car starts, runs, and turns off the way it should, but when the key is in the on position I have current going through the coil wire and also through the brown ignition wire that runs off the small I post on the starter relay. It would make sense to me that in the on position current should be running through the coil wire to provide current for the spark, but I thought the brown wire was only supposed to have power when the key was moved to the start position. Is that correct or incorrect? I just don't want to run it if it is going to fry something else if there is a problem but I don't understand enough at this point about the coil wiring to know if this is right or wrong. Any electrical gurus out there tonight? :p
 

·
Gone but never forgetten
Joined
·
25,239 Posts
Incorrect. The brown wire runs directly to the coil, so will have power on it any time there is power to the coil (which would be any time the key is in the "on" or "start" positions). With the key in the "on" position, it will only have about ~7 volts on it (assuming the resistor wire is stil in place). During cranking (key in "start" position), the selonoid shorts it to the red/blue wire, giving it and the coil and full 12v.
 

·
Registered
Joined
·
159 Posts
Discussion Starter #3
Thanks Johnpro. I was hoping you'd be online tonight. So far just about every question I have had you have answered. I appreciate the responses. I have learned more than I ever expected about electrical wiring. Plus now my SWMBO doesn't have to worry about the house burning down. She wasn't real happy to see the coil exploding.
 

·
Gone but never forgetten
Joined
·
25,239 Posts
She wasn't real happy to see the coil exploding.
I exploded 2 good coils in a week. My daughter's tach was shorting out, and I didn't know it. That's just part of the "sheet happens" ;)

Glad to be of help, and thanks for giving me a big head ::
 
1 - 4 of 4 Posts
Top