wiring problem

[68_stanger]

ok, I have a 68 coupe with a 302 auto. I am still having a hard start problem hot and cold, but pretty much have it tracked down to low voltage going to the coil, when I first turn the key on, I get +/- 6volts to the positive side of the coil, obviously not enough, when the car finally starts gets a good 13 or so going to it. now shut the car off, turn the key back on a good 12 and it'll fire right back up. let it sit for a while, it'll only have +/- 6 volts and requires a bit of cranking before she starts.

Now the question is the "crank" wire apparently has a problem, any reason I can't just run a new one right from the key switch so I know I have a good 12V at the coil whenver the key is on?

btw I am running the pertronix ignition module in place of the points.

 

[mustangmike6996]

whats the battery voltage???? if the voltage matches the voltage at the coil then you may have a current draw when the vehicle is shut off

 

[TOM B]

YOU MUST run a new 12 volt wire from your ignition switch (ON) to the
Pertrinix red wire for it to work properly. Early mustangs have a resistance wire in the dash wiring to bring the voltage down to about 7 volts, this is for POINTS ignition only. If you update your distibutor to a aftermarket electronc distributor like Pertronix, MSD, you must have 12 volts.
Again this 12 volt sourse MUST be switched, do not run a hot wire that is not switched and do not let the key on without the engine running if you have a Pertronix ignition or it will burn it out.