I inherited a 66 impala 4dr hardtop. I'm trying to get it running again. I know it ran when it was parked 10-15 years ago. I have replaced the coil and condensor and replaced the points with a pertronix ignitor. Now I'm only getting 6 volts to the positive side of the coil. No spark before all of that and no spark now. Any ideas where I may be losing the voltage?
Your question is asked often enough that at least ten people have asked the same question before you. You can read the archives (old posts) by typing a few words into the search button above. Google has indexed every word typed on this board (and only this board; so you get responses relevant to your Impala instead of a EFI late model Mustang). Here is some light reading for you. If will lead you in one direction or another depending upon your symptoms.
Thanks for the quick response. I've checked all those links and I still can't get a spark. The starter turns over I'm just not getting enough voltage to the coil. It really shouldn't be this complicated and I'm sure I'm just over thinking it and missing something simple. I just can't figure out where that voltage is being lost. I've checked all connections and wires and fuses.
You are losing voltage because the stock wiring for the ignition provides resistance in order to not burn out the points. Either a resistance wire or ballast resistor. To get a full 12V that you need for your Pertronix, you need to run a wire to a source that is hot in "run".
Thank you. That's kind of what I was looking for. I know the pertronix rep said something about resistance wire but said I could just tie the positive side of the ignitor into another 12v source but that didn'tfix it. Do I need to bypass that resistance wire? If so how would I go about doing that? I'm usually pretty good with electrical stuff just a little rusty.
Problem solved. Took the resistance wire out of the picture and hooked everything up again. Turned the key one time and it fired right up. After a big cloud of black smoke cleared its running like a champ. Thanks
Depending upon which resistance wire you replaced you may have only temporarily solved your problem.
There is a forty to sixty amp fusible link (it is a piece of wire that is very thin and designed to burn open if too much current passes through it to protect the car's wiring). Each car has it's own fusible link that was sized according to the electrical load it had to carry (size of the alternator is a good clue but better to add up all of the fuses in the fuse box).
You can keep the solid copper wire if you add an automotive fuse rated for the correct capacity for your car. These are the type that I use in my race cars. This way I am never stranded on the side of the road because a fuse opened up or a fusible link burned open.
If you have points in your distributor; and have not yet upgraded to an HEI module to replace them (from PerTronix or D.U.I.) then you will need to replace the resistor wire with a suitable resistor (they were sold as external ceramic parts that bolted to the fire wall from 1955 to 1957).