Voltage at coil, '73 318 • The Dodge Challenger Message Board

by **blackmagic73** » 16 Apr 2010 14:12

When the key is in run, should I be seeing +12V at the positive terminal for the coil? Looking at the wiring diagram that's what it seems to me. As it is, the wiring for the new ididit tilt column I got has that brown line that goes to the positive coil terminal wired to the start relay, so it reads hot in start and ground in run. Didn't seem right to me, especially since I'm not getting spark. (For reference, I have a new coil, ballast resistor, voltage regulator, ECU, firewall forward wiring harness). I've traced all the associated circuits and am fairly certain I've eliminated any and all shorts/open circuits.
Can anyone confirm this for me?

by **dave-r** » 16 Apr 2010 15:48

You should be seeing 14v to the coil in start position (by-pass of ballast resistor) and 10v (or whatever) at the coil in the run position (thru the resistor and dependant on how hot the resistor is).

by **blackmagic73** » 17 Apr 2010 16:00

dave-r wrote:You should be seeing 14v to the coil in start position (by-pass of ballast resistor) and 10v (or whatever) at the coil in the run position (thru the resistor and dependant on how hot the resistor is).

OK, definitely not getting that. Got the voltage in start, but nothing in run. Looks like I'm back to troubleshooting. Must've missed an open circuit somewhere...

by **blackmagic73** » 22 Apr 2010 15:26

OK, so after some more work I have 12V at the coil in start (equal to battery voltage), and showing 10.6V on one side of the ballast, 6.5V on the other in run. That voltage seems a touch low to me. Not sure where that voltage loss is coming from...
(Just a note, this is all with the engine not running)