Ok, heres the delema! I just completed a 6v to 12 conversion and reversed polarity, I instaled a new silly-noid ( a mid 70's early 80's mustang type) it has the standard Large terminals at each end and two small terminals in front. One is marked (I) the other (S) if I conect the wire from the ignition switch to the (S) terminal she will turn over, if I conect to the (I) terminal nothing. I have ran the (+) wire from the coil to the (S) terminal with the ignition switch wire, when the key is turned to start she fires then as the key sets back to disingage the starter there is no more juice running to the coil! She dies, and the coil seams to be getting quite hot too! What am I missing here?
You need to have two wires feeding your coil. The one that goes from your starter relay (marked "S") and one from your ignition switch "RUN" position that has either a ballast resistor or a resistor wire in the circuit to bring down the voltage to the coil. You'll get a bit hotter spark when cranking it over to help it fire, and then when you release the key, the resisted source takes over through the run wire from your ignition switch. Flatman
You need a wire from the ignition switch RUN terminal to the coil through a ballast resistor usually. The run terminal will only be hot with the key in the run postion. You can leave the wire from the I terminal as you have it. Its purpose is to byp*** the ballast resistor only when the starter is cranking. It's working correctly. When you release the key to the run position, the coil gets the juice from your ignition switch through the ballast resistor. The I terminal is only hot when the starter is cranking. The coil needs to get its power from the ign. switch run terminal so that you can turn the engine off. If you already have this wire then your ballast resistor is bad.
Your voltage at the coil should be around 9 volts with the engine running. This would be the voltage reduced by your ballast resistor or wire to the positive pole on the coil if it is over twelve volts you need a ballast resistor. The wire to the ballast resistor or ballast wire is from the ignition switch run terminal. And as Tommy said the "I" terminal is used for by p***ing the ballast during cranking only it only gets voltage when the start solenoid is engaged, this wire would also go to the positive pole on the coil. The "S" terminal is the start only wire from the ignition switch to energize the start solenoid during crank. I hope this helps.
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