Resistor Wire, and Firewall Harness Pins (fuse box)

Discussion in 'Technical' started by Kwaz, Jun 17, 2020.

  1. Kwaz

    Kwaz Member

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    Hello all,

    I am swapping in a Pertronix ignition into my 1974 Maverick. My red/green wire is outputting 5.5-ish volts, so I know my resistor wire is still installed. (another resistor wire thread, bear with me i know!)

    Because I have scoured the entire internet, let me help all of you who are attempting to find the resistor wire for a 1974 Maverick/Comet:

    THE WIRE IS NOT PINK. The resistor wire on a 1974 Maverick is red/lightgreen. Now many of you are going to say "well duh", but here's the catch for you guys: BOTH the resistor wire, and the ignition wire are red/lightgreen, but they are separate wires. I have seen countless threads saying there are 2 bullet connectors splicing in a pink wire between the normal red/lightgreen one for all Mavericks. This is not the case. If you are having trouble finding the 1974 Maverick resistor wire, it's partly wrapped in a black rubberish shroud, and is double backed over itself in the main wiring harness directly under the gauge cluster. There are green letters on the wire that say "Resistor".

    Now that that's out of the way...

    I would really like 12v to the coil. I have a Pertronix Ignitor, and a Flamethrower coil. I know, you "could" use it with the resistor wire in place, but I am not a believer in skipping steps and not getting the best performance.

    The resistor wire in the 1974 Maverick is factory spliced into the red/lightgreen wire, and runs directly into the fuse block connector that goes through the firewall.

    Here's my question for you all:

    How do you remove a wire/pin from the fuse block connector at the firewall? I would like to pull out the resistor wire from this firewall connector, and replace it with a new pin and a 14 gauge wire for 12 volts directly.

    I have been unable to find any instruction/threads about how to remove the pins from this connector, it doesn't seem like they push out very easily, and there are no tabs to push in to remove these from what I can see...
     
  2. Krazy Comet

    Krazy Comet Tom Supporting Member

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    You need what's generally referred to as a Molex extractor. Basically a hollow tool that slips over pin & compresses fingers that retain the terminal. Yeah expensive but there are cheap copies. In a pinch, I've used a brass ball point pen refill.

    If you disconnect coil, voltage on resistance wire will rise to batt voltage. That'll operate about any 12v relay, & can be used as switch to feed the Pertronix, & coil. Do not connect anything but relay to the original feed.

    https://www.newark.com/molex/11-03-...MP=KNC-GUSA-GEN-SKU-Tools-Production-Supplies
     
  3. Kwaz

    Kwaz Member

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    Thank you Krazy, awesome reply! I will try the extractor, and fall back to the relay if all else fails.
     
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  4. Krazy Comet

    Krazy Comet Tom Supporting Member

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    I have a relay triggered by resistance wire on my Comet, it's load only drops approx .2v.
     
  5. Kwaz

    Kwaz Member

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    Update:

    Install complete! I now have 12v straight to my flamethrower coil.

    I was luckily able to locate a pin extractor tool set locally at an auto parts store. Here's what I found:
    Pico Pin Extraction Tools 0660PT

    I couldn't find the exact pins, but I was able to use and modify these to fit in my fuse block firewall connector:
    Pico Weatherproof Replacement Pins 5855PT

    I spliced the new 12v ignition wire into the red/lightgreen wire, and she runs much better than before! I hope this thread helps somebody with their build in the future as well.
     
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  6. Krazy Comet

    Krazy Comet Tom Supporting Member

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    Which Pertronix are you using? Unless design has changed, the Ignitor-I requires some current limiting as it has no dwell control. Ignitor-II & III are supposed to be wired direct to 12v source.
     
  7. Kwaz

    Kwaz Member

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    Hey Krazy,

    This seems like a common misconception, which is one of the reasons I made this thread! You will see a lot of people online claim the Ignitor 1 works just fine with the ballast resistor in place... and they're right, it usually does!

    However, you will also see that it's hit-or-miss. Personally, I did not want to gamble on whether it would work or not for my application, so I decided to buy a new 1.5 ohm Pertronix flame-thrower coil, install a 12V source, and Ignitor 1 ignition. I am looking to get maximum spark performance.

    According to Pertronix (see this link to the Pertronix Ignitor 1 1281 instruction manual):

    Recommended Wiring Installation
    "The Ignitor ignition can be used in conjunction with most ignition coils rated at 1.5 ohms of primary resistance on eight cylinder engines and 3.0 ohms on four and six cylinder engines. For optimum performance purchase and install the recommended Flamethrower high performance coil. Many vehicles came equipped with ballast resistor or resistance wire. To achieve optimum performance from the Ignitor ignition system, we recommend the removal of these components."

    The chart for the Flame-Thrower coil also indicates this. See the link here!

    To sum it up:
    • You should use the resistor wire for 4 & 6 cylinder applications, or if not- at least make sure your coil is at 3 ohms
    • If you choose to keep the resistor wire for an 8 cylinder application, you should use the 45,000 volt Flame-thrower II coil instead of the Flame-thrower I coil.
    • Pertronix recommends that 12V is supplied directly to the coil, however you can use the resistor if you'd like.
     
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  8. Krazy Comet

    Krazy Comet Tom Supporting Member

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    OK, I'm skooled... :thumbs2:
     
  9. Kwaz

    Kwaz Member

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    Learning from each other, that's what it's all about! :cheers2:
     
  10. rthomas771

    rthomas771 Member

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    I know a guy with a 66 Fairlane that swapped to Pertronix and Flame-Thrower coil. Car didn't run good. He swapped back to the yellow top coil and fixed the problem
     
  11. Krazy Comet

    Krazy Comet Tom Supporting Member

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    When using a low resistance coil(say one ohm), connecting to the stock resistor wire will result in maybe 4v at coil. Using a three ohm voltage will much higher. It's all about dividing voltage between resistor & coil.

    To make it easy, think of 12 one ohm resistors in series, power supply 12v, resistor at end of string connected to ground. When reading voltage there will be a 1v drop between each resistor. Move four resistors toward ground from 12v, reading will be 8v. At second resistor from ground(junction of resistors two & three), voltage will be 2v.
     
  12. Powerband

    Powerband Member

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    ---- 1976 Comet --- 1974 Maverick- - '61 Comet T'Bolt Six ---- 'quite a few projects ...
    alternate options:

    ... simple way used to modify for full 12V (B+) with hack of wiring harness on my '74 .

    ... with a good schematic , a 12 gauge lead from the handy 'AUX' lug on the fuse box and a Diode to also steer the solenoid 'Start' B+ bypass directly to (rev-limiter) FT ignition module and TFI coil. (BTW - " Fuse box AUX" lug is not powered in 'start' position like accessories)

    [​IMG].



    [​IMG]


    [​IMG]

    have fun
     

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