Ballast Resistor
Short answer: Factory Firebirds used a resistance wire to the coil, not a separate ballast resistor — you should never run both. If your coil has internal resistance, use neither an external resistor nor a resistance wire.
- Measure resistance across the coil: about 1.0–1.5 ohm = no internal ballast; about 4 ohm = internal resistance built in.
- Voltage at the coil should be roughly 9 V with the factory resistance wire (about 6 V if an Accel-style extra ballast is in the circuit).
- During cranking the coil should get full battery voltage (a hotter spark) via a wire from the starter or the ignition switch “start” terminal.
A resistor that runs hot enough to smoke means a wiring problem — typically a doubled-up resistance (e.g., the factory resistance wire plus a ballast resistor). Note the Accel 140001 Super Coil ships with a 0.85-ohm ballast meant to be used with the car’s original resistance, so if you’re running that combo and it smokes, call Accel or switch back to a standard coil. Sort out which single resistance your coil actually needs.
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
← Frequently Asked Questions
Okay where do I start at least once a year I have to replace one of the following. Resistor wire or ignition switch. Or starter solenoid period or coil. I used to use points. And kept having the same problem. More often. I changed my points too a pertronic electronic ignition. After replacing out the points my problem only happens once a year but it’s still happening any advice would be helpful.
RJ67Firebird