Re: got an old 3/4 ton dodge, need some help.
Is it that old that the wire goes from the coil to the distributor?? The you dont have an ignition module do you? You have points in the distributor. and no, there should not be set voltage on the wire from the coil to the distributor per se.
The way it works is:
with the Key on run, you get about 7 volts at the distr. + side. In the start position there should be 12v. The ballast resistor is bypassed in start to get more voltage to te coil for easy starting. in run, the voltage goes thru the ballast resistor to drop it to about 7v so the coil wont burn up.
As you crank the motor, the voltage goes into the + side of the coil charging up the primary winding when the points are closed. As the motor turns, it opens and closes the points in the distributor and this sends the - side of the coil to ground when the points are closed. opening the points breaks the field in the coil and makes a large voltage on the secondary side of the coils.
This large voltage goes into the distributor and out to a spark plug depending on where the rotor in the distr is pointing to. The voltage jumps the gap on the plaug to make a spark.
Real simple setup.
Check the point gap in the distributor. it wont be .007 (thats the gaps for electronic ignition). Im not sure what the gap shouls be but someone should know. Set the gap and see if you get spark. you might need new points or condensor.
Heck, buy a tun up kit points and condensor and install them. there should be a gap setting listed.
let me know what happens.