ignition wire change
Thread Starter
Cruising
Joined: Jan 2016
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ignition wire change
I changed my distributer to a hei and it runs fine but the voltage on the wire from the ignition switch is only 10.5 volts. I read that this wire is a resistive wire to drop the voltage. The wire is black and goes to the fuse box area and have not guite traced out where it goes.The car is a 1973 corvette 454 auto and is stock . I removed the wire from the starter r terminal and it was cloth covered. Wondering if this black wire really needs to be changed or not? I assume that if the wire I am tracing is not cloth covered it then is not resistive. If I need to change it then where do I connect to it. Thanks for the help
Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Now that you changed to HEI you no longer need the wire between the "R" terminal and the coil +.
This schematic shows the "R" wire is yellow.
https://docs.google.com/viewer?a=v&p...ZTM0ZDc1MWM5Ng
This schematic shows the "R" wire is yellow.
https://docs.google.com/viewer?a=v&p...ZTM0ZDc1MWM5Ng
Thread Starter
Cruising
Joined: Jan 2016
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Thanks for the drawing that is helpful. I have removed the wire from the starter to the coil R.Is the neutral safety switch visible under the dash? Is the wire from the neutral safety switch to the distributor a resistor wire?
Last edited by a nickel; Jun 25, 2016 at 09:55 PM.
Race Director
Joined: Sep 1999
Posts: 11,361
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From: Plano TX
The resistor wire goes from the engine side of the bulkhead connector to the coil. You can leave the wire from the starter solenoid to the coil if you want to (although it is no longer needed).
I removed the resistor wire completely on my 71. I took the bulkhead connector off (it plugs into the back of the fuse box), and replaced the resistor wire with a regular one.
I removed the resistor wire completely on my 71. I took the bulkhead connector off (it plugs into the back of the fuse box), and replaced the resistor wire with a regular one.
Thread Starter
Cruising
Joined: Jan 2016
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Thanks. I see the 2 groups of wires going to the back of the fuse box but wasn't sure if they came off, so that is the bulkhead? So I assume the bulkhead should just pull off and can easily be put back. Is there a clip or something that holds the bulkhead in place?
Burning Brakes
Joined: Dec 2003
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once you take the engine harness out you can pull the connector out(cut the eyelet off that connects to the coil,Auto Zone has that exact connector in their electrical section,show the counter person and he'll probaly give it to you as it comes in a package of connectors that you'll never use(my guy did).Just take the wire with you so you can match it up.
Race Director
Joined: Sep 1999
Posts: 11,361
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From: Plano TX
The fuse box is one half of the bulkhead connector, and the other half is in the engine compartment. It's been years, but I think it has a couple screws holding it together. Inside there are simple spade connectors so the engine side contacts the fuse-side. It's actually a pretty clever design. Once you have it separated you can remove the engine-side terminal for the resistor wire. Cut the resistor wire, save the spade terminal, and solder a new wire to it.
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Typical fuse box.
Removing the fuse box and replacing the resistor wire with a new wire is a very good way to do it,
but you can remove the resistor wire and tape the coil end and leave the rest in place.
Then run a new wire from the fuse box IGN terminal to your new HEI.
The resistor wire limits current not voltage.
If you disconnect the wire at the coil and with the key ON you will see 12 volts.
The VOM meters won't read accurately if you check the voltage with the wire connected and the engine running.
but you can remove the resistor wire and tape the coil end and leave the rest in place.
Then run a new wire from the fuse box IGN terminal to your new HEI.
The resistor wire limits current not voltage.
If you disconnect the wire at the coil and with the key ON you will see 12 volts.
The VOM meters won't read accurately if you check the voltage with the wire connected and the engine running.
Last edited by Peterbuilt; Jun 26, 2016 at 06:15 PM.
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Safety Car
Joined: Apr 2006
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From: BC
When I changed my 69 from points to Pertronix I wanted to leave the two cloth covered wires intact in case I want to use points again. I just ran a 12 gauge wire from the IGN terminal on the fuse box to the positive on the coil and left everything else connected as stock. It runs parallel to the resistor wire and leaves no loose disconnected wires anywhere to short out on something and I can change back to points by just unplugging the new wire from the spade terminal on the fuse box. I ran the new ign wire through the hole in one of the upper carpet type plugs on the firewall and it looks stock unless you really know what you are looking for.
Last edited by CanadaGrant; Jun 26, 2016 at 07:17 PM.
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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