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  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

wiring problem

  • Thread starter Thread starter 68_stanger
  • Start date Start date Aug 17, 2007

68_stanger

New Member
Nov 21, 2003
131
0
0
Petoskey, MI
Aug 17, 2007
#1
  • Aug 17, 2007
  • #1
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

5 Year Member
Nov 10, 2005
483
6
29
clinton twp, MI
Aug 18, 2007
#2
  • Aug 18, 2007
  • #2
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
 
T

TOM B

20+ Year Stangneter
Nov 15, 2002
872
1
16
Harrisburg Pa
Aug 19, 2007
#3
  • Aug 19, 2007
  • #3
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.
 
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