blaylock6502
New member
I have a 74 cj5 with a 258. I am still in the process of doing a frame off restoration but its on the road again but I'm trying to work out a few bugs. The radio would cut off and on when first started and after about ten minutes of running it clears up. As the radio is cutting out the autometer tach I installed registers very high (5000 rpm) and gradually comes down as the engine runs. About the time the radio starts to work the tach comes down to close to correct rpm but is very jumpy. I was checking voltages yesterday and found all components were getting around 8-9 volts. I tested the ignition switch and found that there was around 12 ohms resistance between b plus and ignition so I know I need a switch. I hard wired the ignition and the radio problem seems to be solved. That being said my tach acts much better but is still jumpy. I got online and downloaded installation instructions for painless harness I installed. I guess when I was at the ballast resistor part I had thrown back one too many and missed it. I saw it is not a necessity on all coils but as I was looking to make sure I had my tach feed on the correct side of the coil I found the side of the coil says "requires external resistor" so I know I need to hook it up. That being said what does it do? Is it possible It is causing the problem with my tach? Thanks for the input!!!!