Vintage Mustang Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
955 Posts
Discussion Starter #1
Im having an electrical issue and need to test the msd box and the coil. When i test the box by arching the green and purple wire im not getting a spark. Im not even hearing the little buzz from the box.

Is there a way to test the box with out looking for a spark? Can i get a reading from the red and black wire that go to the ignitoin coil?
Thanks
 

·
Premium Member
Joined
·
2,289 Posts
Are you getting voltage to the msd box? If you're getting a "buzz" from the msd box at any time you've got bigger issues.
 

·
Registered
Joined
·
1,217 Posts
I think there are some you tube videos on the subject....
Seems like I remember seeing it.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
731 Posts
The MSD box has two heavy gauge wires (red and black) that need to be connected to the battery.
Two smaller gauge wires (orange and black) that connect to the coil.
And a smaller gauge red wire that gets switched on by the ignition switch.
With all those properly connected and the ignition on, you should measure 12v from the + side of the coil to a chassis/engine ground.

Shorting the green and purple wires won’t do anything. Those are for the trigger sense circuit and must be connected to the magnetic pickup coil in the distributor.
 

·
Premium Member
Joined
·
2,289 Posts
The MSD box has two heavy gauge wires (red and black) that need to be connected to the battery.
Two smaller gauge wires (orange and black) that connect to the coil.
And a smaller gauge red wire that gets switched on by the ignition switch.
With all those properly connected and the ignition on, you should measure 12v from the + side of the coil to a chassis/engine ground.

Shorting the green and purple wires won’t do anything. Those are for the trigger sense circuit and must be connected to the magnetic pickup coil in the distributor.
Actually shorting those two is a way to test for spark. The coil should fire when the circuit is broken.
 

·
Registered
Joined
·
731 Posts
The MSD box has two heavy gauge wires (red and black) that need to be connected to the battery.
Two smaller gauge wires (orange and black) that connect to the coil.
And a smaller gauge red wire that gets switched on by the ignition switch.
With all those properly connected and the ignition on, you should measure 12v from the + side of the coil to a chassis/engine ground.

Shorting the green and purple wires won’t do anything. Those are for the trigger sense circuit and must be connected to the magnetic pickup coil in the distributor.
Actually shorting those two is a way to test for spark. The coil should fire when the circuit is broken.
However, you could use the white wire and hold it against a good ground. Pull the white wire off and you should get a spark.
 

·
Registered
Joined
·
955 Posts
Discussion Starter #7
When i put a screwdriver on the other end of the ignition coil wire, lay it close to ground, and jump the 2 wires i dont get a spark.
I should get an arch from the screw driver and usually hear a little zap. I need to get a coil tomorrow. Im looking for a way to know that the box is sending emergy to the coil
 

·
Premium Member
Joined
·
2,289 Posts
When i put a screwdriver on the other end of the ignition coil wire, lay it close to ground, and jump the 2 wires i dont get a spark.
I should get an arch from the screw driver and usually hear a little zap. I need to get a coil tomorrow. Im looking for a way to know that the box is sending emergy to the coil
Test for voltage at the coil.
 

·
Registered
Joined
·
9,103 Posts
Im having an electrical issue and need to test the msd box and the coil. When i test the box by arching the green and purple wire im not getting a spark. Im not even hearing the little buzz from the box.

Is there a way to test the box with out looking for a spark? Can i get a reading from the red and black wire that go to the ignitoin coil?
Thanks

If you had a buzzing noise from the box and now it doesn't make any noise and you have no spark, the ignition needs to be repaired by MSD.
 

·
Registered
Joined
·
1,096 Posts
The MSD box has two heavy gauge wires (red and black) that need to be connected to the battery.
Two smaller gauge wires (orange and black) that connect to the coil.
And a smaller gauge red wire that gets switched on by the ignition switch.
With all those properly connected and the ignition on, you should measure 12v from the + side of the coil to a chassis/engine ground.

Shorting the green and purple wires won’t do anything. Those are for the trigger sense circuit and must be connected to the magnetic pickup coil in the distributor.
The MSD boxes will not show 12 volts at the + side of the coil. Stock ignitions will.
 
1 - 13 of 13 Posts
Top