RX7Junkman

on my microtech LT-10s, when I used my multi-tester both wires of the ignition coil get power 12v when on should I get only one side 12v and the other nothing? I made sure I didnt cross anything everything looks good except the reading/ please help me out I posted in the microtech section as well but would like to start the car up this week please respond

axr6

Was that with the Ignition Sw OFF or ON?

While I am not picturing the exact circuitry and am too lazy to look it up, here is a potential scenario that would produce both leads reading 12 V.

On many car electrics when the initiating switch is OFF, there is a solid 12 V Pos sitting on the device (like the starter). When you turn ON the initiating switch you provide a negative (chassis) to complete the electrical circuit.

OK now. If the swtitching device is OFF and you have no negative on the device (coil) you will read the Positive 12 V on either side of that coil or device. That is referred to in electrical circuits as a SOFT Positive. Since no current is flowing in the circuit, according, to Ohm's Law, no voltage drop will develop across the terminals of the ignition coil resistance.

V = I * R,

where V=Voltage Drop,
I=Current In the Coil,
R=Resistance of the Coil.

So, if the current is zero than the voltage DROP across the coil will also be zero and the full battery voltage will be seen on both sides.

The moment you start pulling current, as you turn your IGNITION ON, then one wire should be 12 volts, the other should be 0 volts when referenced to the battery negative post (or chassis).

Hope this helps, looks like everything maybe normal. Just turn On your ignition and repeat the voltage readings on both wires.

Albert

RX7Junkman

I figured it out thanx, axr6