67 Barracuda Ignition Issue

Just for grins, I took a reading with the key off from the battery to coil positive and got 2770 Ohms. My meter switches automatically. Don’t know if this means anything.

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As I attempted to elude in my post, taking random readings does you no help, and may just confuse us. Try to picture this:

The one side of the ballast is exactly like breaker points, That is, key "run," through the ballast, to coil + through the coil and to ground through the breaker points or in this case through the ECU box. The ECU is supposed to draw current when the key is on, so you want "same as battery at the two ballast connections which are jumpered together, there, on one end.

You want about 6-10 at coil + which shows the coil is drawing current

.6 at the coil NEG seems low. Most boxes only pull the coil NEG to about 1--2 volts. .6 might indicate low power TO the ballast and coil. Again, you should have close to battery at the key side of the ballast

The remaining side of the ballast IS LIKELY NOT USED. This is because ONLY the original 5 pin boxes needed a 4 pin resistor. If your box is a 4 pin (and may have 5 physical pins, ) then the "box" side of the resistor will measure same on both ends---about battery voltage with key on.