How to test ignition voltage
#1
How to test ignition voltage
My '68 442 has a '70 455 with HEI. Rebuilt 455 running E85 going in soon with electronic ignition (MSD ready to run) and was told need to be sure it has upgraded ignition wires that provide 12V to coil/distributor as most pre '70 cars has a resistor wire. Car runs hella rich now so I wouldn't be shocked if it had inadequate spark. How do I confirm what wires it currently has? I do have a voltmeter but don't know where to begin.
#2
Who installed the HEI? It requires full battery voltage also. The resistance wire is stiffer than your standard wire. You can measure the voltage with the car running on the Bat+ terminal in the HEI cap.
#4
You can buy the special connector body with a series 56 terminal that will plug in and lock into the distributor cap, or cut one from a donor car. The best place to pick up the proper 12 bolt power source would be to remove the bulkhead connector from the fuse box, pick out the series 56 male terminal with resistance wire from the bulkhead connector, and reinstall the proper wire (14 gauge would be good). If that’s too much work, another option would be to tap into the pink wire at the ignition switch.
#5
Thanks Matt. I guess I need to remove the cap and see exactly what the Batt connector looks like. I was thinking/hoping I could place a voltmeter lead on there quickly as I really just need to confirm if I am getting the full 12v to the coil or not but it’s so buried back there. The ‘68 hoods don’t give you much help either.
#8
Not sure why I need spade connectors unless I did it incorrectly. I removed the dust cover, which was held on by three screws, and the Batt connector was right there. 12.4V in “key on” position; 11.4V at idle. Only hit my head on the hood 4 times which is a personal record for me.
I'd say your good to go. Feel your pain on the hood..
I'd say your good to go. Feel your pain on the hood..
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