duanem1

Thanks for the help on this. It helps to understand the kind of readings I should expect to get from this part of the ignition system. I will continue to drive and see what happens. Have just gotten the car up and running after a long process of restoration. Still sorting things out but this helps with this part. Thanks again. duanem1 Post Falls, Idaho 1972 240Z

That is encouraging. Thanks for your input. The change in the readings when the engine is off occur with no change in the point position. In other words, I measure the output end and get a 12+ reading, and shortly, with no change in the engine position, a 6+ reading. That has concerned me. The reading you describe with the engine running makes sense. But, as you say, I will drive and enjoy and see what happens. Just getting it back up and running after restoration. Thanks again.

Checking voltage from end of resistor going to coil and ground. Checking it both when running and when stopped. I agree with you that it is hard to see how it could fail, but when at one point it reads just over 6 volts and a few minutes later reads over 12, (engine stopped) something is going on. Trying to avoid point burning with 12+ volts going to coil. It would seem to me that the resistor should either impede the flow of elec. or not carry current at all due to a burned wire.

I need some help understanding (and perhaps correcting) a problem with the resistor on the ignition system of my stock 240Z. I am on the 2nd new one in a month and the same condition exists. I understand that running the car without the resistor will burn the points quickly, however with the resistor hooked up I am often getting over 12 volts coming out of the resistor. It seems to flip back and forth. At times it is only slightly over 6 volts, then for no apparent reason it reads over 12. (This is without the car running but with the ig. switch in the run position.) When the car is running it reads over 12 volts coming out of the resistor. How does this resistor work? Why will it cut the current to about 6v and then go back up to 12+? Have I missed something in the wiring of this? Is there some fuse in the resistor that is not apparent? This is the ceramic resistor with a coiled wire in it. Doesn't seem to be a place for any fuse. Any answers?