PcWilliams
Member
Hi all. Seems i'm not getting full voltage to the coil. I'm getting about 5 volts when i think i should be getting about 8 (?). Any ideas?
I believe running. It was my mechanic's and he said it was only getting about 5 volts. I assume he meant running. It runs like it's weak.5V with engine running or not?
Measure the voltage on the other side (feed side) of ballast resistor. It should be about 12 v. If it is, your coil or ballast resistor could be bad. I am assuming you have a ballast resistor.
If it is a stock ignition ballast resistors and coils are pretty cheap. I would shotgun both.
If voltage is not near 12 v, more troubleshooting of supply circuit will be needed.
Measure the voltage on the other side (feed side) of ballast resistor. It should be about 12 v. If it is, your coil or ballast resistor could be bad. I am assuming you have a ballast resistor.
If it is a stock ignition ballast resistors and coils are pretty cheap. I would shotgun both.
If voltage is not near 12 v, more troubleshooting of supply circuit will be needed.
This may or may not be a good strategy
1....You want to find out that there is or is not (should not be) voltage drop between the ballast resistor ignition switch feed, through the harness, switch, bulkhead, all the way back to the battery
2.....Ballast voltage will vary A LOT depending on whether idling slow or engine off, etc, the type of coil you are running, and just plain variations over the years
So........
To check for voltage drop, with engine off, turn key to "run." Measure voltage between battery POS post and the keyswitch side of the ballast. You should have a VERY low reading, the lower the better. More than about .3V (3/10 of one volt) means there is voltage drop in there
2....Check coil+ voltage both with key on / engine stopped. and engine running at low idle.
Check again, rev engine up to simulate "medium cruise" RPM IE as if you were cruising down the street at 40-45 mph
Here, battery should read nominally 14V (13.8---14.2 if warmed up) and coil will read 10--12V +/- again, depending on the coil
Yeah, agreed on the troubleshooting 67Dart. Just thought that for a non electronic guy replacing the two obvious parts might be a cheap first shot. Everything else gets a lot harder.