Ignition switch problem (starting)

[pedal2themetal]

HI, (75 Fury, Custom) I've had the switch replaced once and in less than a year its doing it again.. Its a typical (you/I would think) switch problem when starting (starter well spin but no fire). When Cold it starts right up.. but after you have driven it. It won't start if you fully engage the switch to full start position. if you barely engage the start position it well start right up (getting harder to find this sweet spot). Am I going to have to replace it again or could there be another possibility I'm not seeing or know of? OH ballast resistor had been replaced.
Thanks
Tim

 

[451Mopar]

Use a volt meter on the ignition wire and wiggle the switch to see if you actually loose power from the switch.
If you don't loose power from the ignition switch, the switch is likely fine.
The "won't start when hot" problem can be different ignition related issues.
When I had this problem, it was actually caused by a bad battery ground cable. Too much resistance when cranking the car.
Some times it could be a bad coil, or distributor pickup and gap, or even the ignition ECU and how it is grounded.

 

[pedal2themetal]

Thanks 451. I don't think its a hot issue. as even when I go into the store for like an hour of more it won't start if I fully engage the start position , it well crank and crank until I back it off just a little on the start position then it well fire right up? maybe I'll check voltage at the coil. on full engagement it might not be getting the full 12V for start up? If I crank and crank on it sometimes it well fire up.. But if I barely engage it or back off a little it well fire right up. Do you know which color wire off the loom set is the start wire I can check under dash?
thanks again 451.
tim

 

[451Mopar]

Just check the voltage at the ballast resistor. The actual voltage (11-13 volts?) is not what your concerned with. just if you loose the power connection. Disconnect the start wire from the relay so the engine does not crank, then you can move the ignition switch to different positions to check if it is the problem.