maverick quiz for the tech

i have a 73 maverick, and there is a wire behind the instrument cluster that is a fuseable link that goes to the coil...when the car is running the wire gets hot...when the key is on and the car is not running it dose not get hot..the car does have the aftermarket billet MSD distributer that works with the coil..it is a plug n go distributer w/o points...i have changed out the coil, ignition, unplugged the alt...what could be causing this problem???and i have already checked the wiring and made shure it dosnt have any cuts or shorting out..any ideas??? thanks for the help yergntiger93@yahoo.com

 

Its a resistor wire to step down the voltage to the coil so ford didnt have to install a ballast resistor.

 

How hot does it get? Almost sounds like the resistor wire for the old points.

 

Aaahhh ya beat me to it.

 

it gets hot enough that it feels like it will melt the wiring

 

any ideas as to why it will get soo hot

 

could the distributer be bad?

 

I dont think it would hurt it to remove it and just put in a heavy wire. Its there just to protect the points.

 

Are you sure the dist/coil is compatible with the stock wireing and doesnt need 12 volts to the coil???

 

resistor wire 411

Back in the day coils would run at 6-8volts, this would allow for long lifespans. The ballist resistor is designed to drop the 12volts down. At startup the starter relay provides 12volts, after the engine starts the coil then runs off the resistor wire. My guess is your modern ignition is trying to pull 12volts through that resistor wire. This causes the wire to overheat and WILL FRY your dash wiring!.(I just got done rewiring my resistor wire) The best solution is use the resistor wire for relay trip. This would allow you to run 10gauge wire to your stuff.(plenty of wire your high power setups) Also if you want its a great time to install a kill switch.

 

the coil is an MSD aftermarket coil as well..car has been running for some time and didnt really notice it untill my son had the instrument cluster off and was testing the plug in for thr instrument cluster..somewhere in there it sparked and ??but i just dont know??

 

The best solution is use the resistor wire for relay trip. This would allow you to run 10gauge wire to your stuff.(plenty of wire your high power setups) what are you refering to as a relay trip?

 

My car is a 73 and i use the wire that was in the car when i got it and its worked that way for 10 years. I also have all msd stuff to but id have to hunt down my part numbers. before that i used mallory stuff and never had an issue.

 

if it is the resistor wire it's right there...resistance causes heat. if it is a resistor wire to take the place of a ballast resistor and u dont have points i dont think u need it(run a new wire and get better spark) but i would ask around before going through with it. this is just an educated guess

 

The quick answer is:
You should not be using a ballast resistor with your MSD Electronic Ignition system and Coil. I agree with Mavman72, GreaseMonkey, and Random Hero.
Your MSD Coil would require one ballast resistor, only if it was connected to the old points style distributors, which in your case it is not. With your MSD billet Distributor being an Electronic Ignition style, you will not need the existing ballast resistor that is in series between your ignition switch, and your engine fire-wall plug.
Longer explanation - (nothing that the electrical tech members on here don't already know, but I will post anyway):
When an inline, or ballast resistor is used in series with an older points-style, or newer electronic ignition, the resistor normally is hot to the touch when the engine is running. This is due to the inrush current passing through the resistor, every time the coil primary winding energizes. (and de-energizes on older styles, upon points-open/spark fire)
It is true that the ignition coil ballast resistors, are used to drop down the voltage about 15%, in order to protect the points from premature wear in older distributors. The Condensers, in the old points style systems were used to keep the points from burning out also, as well as preventing the radio noise that would otherwise be generated by a spark jumping the points gap.
If you are using an electronic ignition system, make sure you're using the new electronic ignition style coils, that produce higher voltages (around 50,000 V). They can handle higher energy, as opposed the older points-style coils, that produce around half that, and should not be handling the higher energy that is present with no ballast resistor.