Ignition Resistance Wire-Needed or Nah

[projectmidnight74]

Good evening gents. Project Midnight, my restomod project for my dad is gearing to somewhat of a completion. I have removed it from the original shop to finish it up on the brightwork and minor details as I can on my own. So here is my dilemma. We put in a donor SBC 350 with some work done to it. We went with a HEI distributor system which is working fine. Truck starts, runs, etc. Just need a fuel pressure gauge to dial it in. My problem is I have this wire, that is somewhat pink in color that gets HOT after starting and remains hot. Like, melting electrical tape HOT and only while the truck is running. I have driven he truck a few times to break it in and nothing has happened which is good. But I know that is not a normal thing. From my research, I think this may be the original ignition resistance wire from when the truck ran a coil. Its a 1974 by the way. Is it safe for me to remove this wire from the set up, as whatever it is tied to may not be needed either. I'm just trying not to burn the truck down before I have a chance to present it to the oldman Let me know what you guys think.

 

[Ricko1966]

Good evening gents. Project Midnight, my restomod project for my dad is gearing to somewhat of a completion. I have removed it from the original shop to finish it up on the brightwork and minor details as I can on my own. So here is my dilemma. We put in a donor SBC 350 with some work done to it. We went with a HEI distributor system which is working fine. Truck starts, runs, etc. Just need a fuel pressure gauge to dial it in. My problem is I have this wire, that is somewhat pink in color that gets HOT after starting and remains hot. Like, melting electrical tape HOT and only while the truck is running. I have driven he truck a few times to break it in and nothing has happened which is good. But I know that is not a normal thing. From my research, I think this may be the original ignition resistance wire from when the truck ran a coil. Its a 1974 by the way. Is it safe for me to remove this wire from the set up, as whatever it is tied to may not be needed either. I'm just trying not to burn the truck down before I have a chance to present it to the oldman Let me know what you guys think.

Where does the wire go to and from?

 

[projectmidnight74]

Where does the wire go to and from?

glad you asked. Just noticed that they wired the HEI distributor RIGHT TO THAT MF WIRE. Thats not correct, or am I Wrong.

 

[Ricko1966]

glad you asked. Just noticed that they wired the HEI distributor RIGHT TO THAT MF WIRE. Thats not correct, or am I Wrong.

Thats not correct , disconnect that wire at the distributor. Follow it back to the firewall. Rerun a new wire from the firewall to the distributor. Wrap them both into the loom. To look nice but still be able to go back if you ever needed/wanted to.

 

[projectmidnight74]

It just needs a solid 12volts right. Nothing more nothing less for the HEI? I should be able to pull that from the fuse panel on the ignition fuseable slot that's open.....right?

 

[projectmidnight74]

Problem now resolved, but I am a little troubled by other things being wired to that wire still. Fuel pump, which is electric and electric choke are both wired to that. Kits out 9v while motors running but the wire cooks for some reason. we will figure out the rest. In the meantime, thank you for the kind help.

 

[Ricko1966]

It just needs a solid 12volts right. Nothing more nothing less for the HEI? I should be able to pull that from the fuse panel on the ignition fuseable slot that's open.....right?

I just run them right from the junction at the firewall. Use the same pin just regular wire.

 

[Camar068]

Problem now resolved, but I am a little troubled by other things being wired to that wire still. Fuel pump, which is electric and electric choke are both wired to that. Kits out 9v while motors running but the wire cooks for some reason. we will figure out the rest. In the meantime, thank you for the kind help.

sounds like you have a wire/connection thats about to break. Imagine it like too small a wire for something that draws a lot of power. Follow it back and check for wire pinches, corrosion....anything that would cause it to not be a solid run.

Also, you might be running too much on that one wire.

I'd disconnect the choke and take another measurement where you got the 9v. If the voltage increases, your on the right path. Something is drawing it down.

If you feel that all of your loads are good, you can always use that wire to control a relay that sends battery power to those loads.

 

[Camar068]

Also, another way to test the wire thats getting hot is to ohm it out to the battery.

DISCONNECT THE BATTERY FIRST. Then put one meter lead on the positive connector that connects to the battery, then put the other lead on that wire thats getting hot. It should be close to zero with the key in the run position. Move/wiggle that wire thats getting hot around and see if the numbers change drastically also.

post meter readings to help us.

 

[projectmidnight74]

Also, another way to test the wire thats getting hot is to ohm it out to the battery.

DISCONNECT THE BATTERY FIRST. Then put one meter lead on the positive connector that connects to the battery, then put the other lead on that wire thats getting hot. It should be close to zero with the key in the run position. Move/wiggle that wire thats getting hot around and see if the numbers change drastically also.

post meter readings to help us.

I went the other route. Found a solid fuse in the panel and linked the blue wire from the distributor to that. I had it wrong at first and the truck wouldn't turn off because it was hooked to a battery fuseable lead LOL! Boy did I learn something tonite. Next step is to take that same lead and run it as power to a new fuse bank and wire all my needs from there on the proper fuses. Radio, fuel pump, lights for tach, voltage meter, auto choke and oil pressure and tach. Wish me luck. For now, that original wire is still running the fuel pump and auto chocke until the switch happens.

 

[Ricko1966]

I went the other route. Found a solid fuse in the panel and linked the blue wire from the distributor to that. I had it wrong at first and the truck wouldn't turn off because it was hooked to a battery fuseable lead LOL! Boy did I learn something tonite. Next step is to take that same lead and run it as power to a new fuse bank and wire all my needs from there on the proper fuses. Radio, fuel pump, lights for tach, voltage meter, auto choke and oil pressure and tach. Wish me luck. For now, that original wire is still running the fuel pump and auto chocke until the switch happens.

That original wire is resistance wire like a toaster element NP pulling the little needed for the coil but the volts aren't there. Also not sufficient for running the choke or fuel pump,incorrect voltage and your by product on the resistance is heat. Use it to trigger a relay. A common four prong relay. Terminal 30 to battery, you can pick it up at the back of the alternator if you like. Terminal 87 to your choke and fuel pump. Termal 85 to ground .Terminal 86 to the alternator warning light wire or to your resistance wire. Preferably the alternator light lead. That way the pump and choke only get power when the alternator is producing voltage. But the resistance wire,will not overheat triggering a relay and 9 volts should be no problem closing the relay. Also pulling the amperage of the fuel pump and the choke through the stock ignition switch instead of a relay will be hard on your ignition switch.

 

[Ricko1966]

Also, another way to test the wire thats getting hot is to ohm it out to the battery.

DISCONNECT THE BATTERY FIRST. Then put one meter lead on the positive connector that connects to the battery, then put the other lead on that wire thats getting hot. It should be close to zero with the key in the run position. Move/wiggle that wire thats getting hot around and see if the numbers change drastically also.

post meter readings to help us.

Except for it is resistance wire for an old point fired distributor. It has resistance to drop the voltage to 9 volts so as not to burn points. The by product of the resistance is heat.

 

[Camar068]

Except for it is resistance wire for an old point fired distributor.

good to know, never delt with points. Sounds like he needs to find another source for power then? [edit] I see and understand your answer now lol.

 

[Ricko1966]

good to know, never delt with points. Sounds like he needs to find another source for power then?

Told him where to get it on my 4th post. Told him how to wire a relay for the choke and fuel pump on another post. We'll see what happens.

 

[Doppleganger]

You fellas know more about it than me, but I'm a huge fan of relays and surprised they aren't discussed more with trucks that had few to none - especially after we mod them. I worked on cars for years that loved to dump 2-3 25A+ circuits on a single 30A relay and then talk about its browning/heat-failures were 'normal'. I used the original relays as a switch for 2 separate 40A relays and all was well.