Today I started poking around the engine compartment with a multimeter.

Now I'm thinking about how to minimize voltage drop (primarily in my ignition system). So, what are the common under-the-hood wiring upgraded? Also, I'm on a bit of a budget so what are the most effective upgrades (again, focusing on the ignition system).

Is it as simple as using new wire and maybe upping the gauge of the wire (anybody have tips on choosing wire gauge)?

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'66 Dodge Dart

Corroded connections, poor contacts, and bad grounds generally cause the most resistance problems, followed by degraded wire or crappy splicing.

If a wire’s insulation is hard or brittle, and or has splices from previous hacking, it should be replaced with correct gage and color per FSM. All connections at the bulkhead connector both sides are suspect, so look them over closely, and replace as needed.

My car had a lot of electrical problems when it got it March of 08. I replaced most of the brass connections from the front doors forward, the burnt bulkhead connector with a NOS unit, fuse block, and a lot of the wiring under the dash & hood. Also, I made sure that all grounds were good connections, including a ground strap connecting head to fire wall, and a ground wire to the chassis of the orange box, and all exterior lights. I have not had any problems with electrical issues since.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

So I should go with the wire gauges outlined in the FSM? I thought at least a few of these were considered a bit small?

Also, the previous owner did an electronic ignition conversion and its currently got a dual ballast resistor, however the bottom two terminals have a wire that connects them together, and the car won't run without this wire. So I'm wondering if I should be using a single ballast resistor? Also, where can I find a new ECU wiring deal (the one that plugs the 5 wires into the top of the ECU).

Most of my terminals looks pretty solid, however much of the wiring is either hacked together by the previous owner, or old and needs replacing. Anybody have an idea on how much it would cost to replace all the wiring for the ignition and charging system on the engine side of the firewall?

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'66 Dodge Dart

Josh, we are talking about your '66, right?

If the car is still stock, you don’t have a ton of hi output sound system stuff filling every cavity, haven’t up graded the headlights to hi output units now available, I think the stock wire gage will do fine.

The one exception would be that if you want to install a higher wattage headlight, you may want to consider installing relays and heavier gage wire to feed them. This would yield more lumens being emitted, and a lot less amperage passing through the head light switch, and less heat.

As for the ignition circuits, the factory sizes will be fine provided you eliminate all resistances from old, corroded electrical devices. Remember green and white stuff on the brass, or copper conductors mean resistance is a problem at that point.

My 67 has been converted to electronic ignition, uses a single ballast resistor (two prong), and only four of the five terminals are used on the orange box as shown in the lower diagram. Here are two diagrams showing single & double resistors.

Get a wiring diagram for your car, make several copies that can be clipped to a clip board, and slowly & methodically trace each wire, assess its condition and correct any defects found, and than mark it off as fixed on the clip board. Keeping track of progress will eliminate duplication of effort, and teach you what is going on with each circuit. This may mean replacing the brass connectors, and or wire. If you discover any splices in the engine compartment, replace the wire so that there are no more splices between brass connectors. These splices can be very troublesome due to the harsh environment under the hood.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Thanks wjajr!

Yep talking about my '66 Dart. The car is more-or-less stock, other than the electronic ignition. I do one day plan to upgrade the radio and headlights, and also a slightly higher output alt. (in the 70-100A range).

Regarding the dual vs single ballast resistor... can I convert to a single ballast resistor by using the other style ECU connector? Is that a bad idea? Not really interested in doing this, just curious and would like to understand the differences more.

I guess its time to start looking around for deals on wire of the various gauges and colors....

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'66 Dodge Dart

Which ever way you want will work. Just follow the diagram.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Considering the wiring was meant for the original 36 amp alternator you will want to upgrade the alternator wiring. 2.5X the current is not going to flow without serious consequences.
If you have a 4-pin ECU you can use a single ballast resistor now.

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Joshua