7.5 volts at coil + (1 Viewer)

[John Smith]

When I put the key in the run position I'm only getting 7.5v on the + side of the coil. Anyone ever experienced this before?

 

[pb4ugo]

How much voltage do you get on both sides of the ballast resistor?

 

[pb4ugo]

Also please tell us what you are working on.

 

[pb4ugo]

The ballast resistor reduces voltage to the coil, so the points don't burn up.

 

[John Smith]

This is my 79 with the stock ignition system. So no ballast or points. Electronic with the ignitor and coil.

 

[Steamer]

Not familiar with your system but,
I'm just having a look at a 1979 schematic from Coolerman and it shows a ballast resistor with the electronic ignitor system.

The first PDF under "1979 FJ40" HERE

 

[Steamer]

 

[John Smith]

I've had this truck over 20 years and never had a ballast resistor on the coil, and it ran fine until yesterday. I'm guessing the ignitor is bad. I was hoping someone had experienced this, and could point to either the ignition switch or the ignitor. Time to pull out the power probe and start testing wires. Or just throw my backup coil and ignitor on and rule that out.