Perfect Bob. Why didn't I see that before? Been all over this diagram for a month and never saw that. Do you know which portion of the coil wire from the ign switch is the resistance section? I kind of assume it's the run from the bulkhead connector to the coil in the engine compartment. If that's the case I could probably snip it and tie into it close to the junction block and not lose any voltage. At least then it would already be on the correct side of the firewall. I suppose I could separate the bulkhead connector and check it with a volt meter.
Just checked voltage on my coil wire. Battery voltage is 12 volts( been sitting awhile without being started)( batt is in the trunk). I'm getting 11.4 at the coil end. It's a long way. .6 volt drop is not too bad. I'll bet when the batt is fully charged at 13.7 or whatever, I'm probably getting a full 12 volts to the coil end. Odd...I guess this harness didn't have a resistance to the coil wire. It's not pink, it's gray color. It is a 69 harness though. I'll check cranking voltage when I get some help but I think I'm good to go.
If you look at the wiring diagram it indicates the pink wire is not hot during cranking. Someone here insisted it was and I tested it and they were right.
I forget where the original wire runs from but I assumed the whole run was stainless steel.
0.6 volt drop through a few connectors and feet of wire is not much at all for forty old wiring, mine was about 10.8 volts at the switch.
Sounds like you are trying to get 12 volts to your ignition when running? I mounted a relay on the firewall near the HEI. I use the pink ignition wire to turn the relay on and off, the low voltage of the pink resistor wire is plenty to turn the relay on and off. I run a wire from the terminal block I have mounted on the drivers side of the firewall, with full alternator/battery voltage to the relay that provides 12+ volts to the HEI when starting and running. Simple and works great.
That’s fancy. Plenty of amps to the coil. I tie into the light gauge pink wire that runs the directionals. Seems to work ok but I wonder if I’m pulling too much current from that circuit. One day I’ll be driving, put my turn signal on, and smoke the wiring.
Don't forget there's two circuits that originally fed the coil, the resistance wire in "run" and the non resistance wire that supplies full 12V during cranking.
Or maybe the engine will turn on and off with the signal lights. My horn used to sound whenever I turned around a corner. I eliminated the start circuit from the starter when I put in the HEI. My run circuit is hot with the key on start or run.
You know I'm not convinced that 69 had two wires running to the coil. My old original harness only had one and my current 69 harness also only has the one. The harness in the car currently has a gray colored wire that went to the +coil terminal. It's gray now, maybe it was pink when new and has faded but it's definitely copper too. Not nickel tungsten or whatever. The wiring diagram only shows the one wire coming from the starter going to the coil and it isn't noted as being a resistance wire.
That's a good idea about using the coil wire as a trigger for a relay. Easy enough to do.
You are right! My 67 bird had 2 wires to the coil. In 69 there is one wire from the firewall to the coil. I looked at the wiring diagram. There are 2 wires between the ignition switch and the firewall connector. One of those is the resistance wire. One is yellow and one is “black pink print†which is the resistance wire.
Some of the harnesses had the start circuit wire junctioned to the resistance wire in the harness up stream from the coil instead of going to the coil itself. Worked the same but only one wire at the coil.
What about the idle solenoid wire? My car, 68 not 69, has a green wire coming from the firewall connector block that I'm sure was hot in run and stop. Have my engine out and wiring apart so can't check now. I'm sure it was a wire going to an idle solenoid. Just going by memory here, but it seems to me there were two solenoids on some cars, and some were activated when the AC came on, some activated when the engine got hot and some came on with the ignition to give the proper idle speed. If a car did not have a solenoid the wires were usually still there. Easier to make just a few harnesses and use the wires if needed. When the smog stuff started the ignition timing was retarded and the idle was set higher to keep the cars running at idle. Trouble with that was engine 'run on' or dieseling. A solenoid was put in to move the throttle plate to fast idle when the key was on, then when the key was off the solenoid dis-energized and the carb idle was lowered. Solved the 'run-on'. The idle was set by adjusting the stop against the activated solenoid plunger.
You may have that wire in your harness even if you don't have a solenoid, But then maybe you still have the solenoid operational on your car?
So you all are saying the resistance portion of the coil wire may be in the passenger compartment section of the run? Would make sense why I've not found it in the engine comp section. The question would be the same with the idle stop solenoid, whether or not it is hot during cranking as well as run positions. At least it's one more option to consider. My harness had two connectors next to the carb. I know one was the kick down switch. The other either also went to the kick down or to the ISS. My original harness had no connectors there. It was a 2bbl/4sp no AC car so no need for kick down or idle stop either.
I'm going out today to pull the intake for some adjustment. Once that goes back on I'll be doing the wiring so I should have a good idea of where to go for my source. I only have a couple of options so it won't be too hard to pick the best one or my needs.
So I went over the wiring diagram a little better this time. Turns out you guys were right. It say the resistance wire is run parallel in the passenger comp harness. One wire is hot during cranking and the resistance circuit during run. Now I'm not sure why I had 11.6volts at the coil wire with the key on. I thought the resistance wire knocked the voltage down to around 9volts during run so the points didn't roast prematurely. If it only supplied 9volts to the coil I'm surprised it was enough to charge the coil. I'm going to have to do a bit more investigating. There is one pole on the ign switch that isn't used and is hot during crank and run but I don't really want to tear the whole column apart just to add a new wire
I think I'm just going to use the coil wire as a trigger for a relay. Other people have done it this way and it seems to work for them. Hopefully I won't have issues with electronic " noise" interference. I guess these EFI units are kind of sensitive to it.
Bob S. is right, there has to be a current flow to get a voltage drop. The resistance wire has about two Ohms of resistance. The current draw of a coil is about 3 amps. two ohms times three amps is 6 volts. If your alternator is putting out about 14 volts you would have about 8 volts at the coil. 14 volts less the 6 volt drop. If the coil drew less amps the voltage would be higher, if it had a heavier draw the voltage would be lower. When you connect the meter to the circuit, if the points are open the only draw is that of the meter itself which is quite low so you have a small voltage drop across the resistance and a higher voltage at the coil. Those lost six volts of energy have to go somewhere. Energy cannot be used it's converted into another type of energy, in this case heat, thus the different heat resistant material in the resistance wire and insulation. If you have a car with a ballast resistor in the ignition circuit, you can feel how hot it gets when the engine has been running for a while.
Another good thing about using a relay to power your coil is the relay takes very little energy to operate, but gives full alternator voltage to the component it is powering. You can use one to power your fuel pump as well. A small wire running to the relay to switch on and off and full battery voltage to run the pump. You have the battery in the trunk so it is close to the pump.
Thanks for the 101 Al. I never knew that's how that operates. Makes sense why I was getting full voltage without any kind of draw. I was using that coil wire to power my MSD box because their instructions say down to 9 volts is still good but I have to wonder if I was getting everything out of it running off the resistance circuit. Relay is already wired in place for the fuel pump. I'll use the feed from the ECU to trigger it. Now I have a new problem. If I use the coil wire to trigger the relay for the for the EFI then what will I use to trigger the relay for the MSD box? I suppose I could jump the same wire to trigger both but someone said you need min 10.5 volts to operate the relay. Hmm. I may end up adding that extra wire from the ignition switch after all Ooooooo. I just thought of something...I can rewire the wires on the ign switch so the resistance wire isn't used anymore. Move the full power feed wire, that is only used in cranking now, to the pole that gets power in both modes. That'll do it. Dam! More work.
I wouldn't worry about the volts to operate the relays. It takes less than 0.1 amp to close the contacts in a typical relay, Bosch or equivalent, even though they can switch a 20-30 amp circuit. You have 14 volts going through a 2 ohm resistor with a 0.1 amp draw. 0.1 amps X 2 ohms is 0.2 volts. you have 14 volts less 0.2 volts 13.8 volts. It will work, use the same wire for both. Use the same wire to run a few relays. I do not have a relay distribution business, and this is just my opinion. But it works for me.
Just re read your last post. If you think you are not getting enough voltage to operate your MSD box use a relay to power it and the ignition wire to trigger the relay.
Last year I built a 72 Nova for a guy who wanted to go to a poinless ignition that needed full voltage too. The resistor ignition wire had plenty of volts to power a relay. It worked great. We also used the full voltage out of that relay to signal a second relay to run the fuel pump. Just a thought.
I'm pretty sure I have enough voltage through the resistance wire to trigger one relay, I just was not sure if there was enough to daisy chain that to trigger two relays. One for the MSD and jump off to trigger the EFI nit as well.
You could trigger all of them with the ignition wire. Hook up in parallel, say three relays. Even with out the alternator running if the battery voltage is 12 volts and you have three one amp draws through the two ohm resistance wire, you have a total of 0.3 amps. Mr Kirchhoff says the sum of the current entering a junction is equal to the sum or the current leaving a junction. so the current through the resistance wire is 0.3 amps. And as Mr. Ohm says, Voltage is current times resistance, so 0.3 amps X 2 ohms is 0.6 Volts. You would have a 0.6 volt drop across the resistance wire. You started with a battery voltage of 12 volts, 12-0.6=11.4 Volts. Plenty to trigger three relays.
Or as cme469 suggests you could install one 20-30 amp relay to supply Ignition switched power to your under hood dash area.we'll call that relay relay M [main relay]The resistance wire would switch the relay off and on. You feed that relay full alternator/battery voltage from the harness main splice or from the BATT. junction of the alternator, through a fusible link to protect the circuit. You then run a large wire from relay M to a junction [junction 1]. Junction one now has ignition switched 12 volt power capable of supporting 20-30 amps of current draw. From junction 1 you can connect the ignition box, efi, hour meter, switched power to the dash or whatever else you want. Or even better you use the power at junction one to trigger relays for the ignition, efi, fuel pump, or any other circuit that is ignition switch activated.You could run some circuits from junction 1 with relays involved and some directly to whatever the component is. Or you could not get too carried away and just use the Main relay to power both the ignition and the efi
I'm used to that, my wife's eyes glaze over and she get's a sleepy look. Not that she doesn't understand but more like she hasn't interest in 'how things work' stuff, or could be I'm just boring. I added seven relays, two junction blocks, three breakers, five fusible links and one diode to mine. I don't have to worry about wiring problems but the engine is down to the bare block thanks to the defective lifters and rockers. Sigh.
Seems like a common theme. I usually get about 3words out before I stop and says do you really want to know? Almost always the answer is no, not really. In this case I could try to understand but elect stuff just seems like magic to me. Kind of like the telephone and why planes stay up in the air. And what the hell is the cloud anyway?
If you mean the internet-computer kind of cloud, I don't have a clue. My antique computer is more than I can handle and since I'm over 65, never had kids/grand kids/great grand kids to teach me and still use a slide rule I'l most likely never know what the cloud is. I do know the white fluffy ones, after going through them in free-fall you can roll over on your back and see the hole in them. Just like the cartoons. That, why aircraft stay up, how the telephone mounted on our kitchen wall with the rotary dial and the curly cord works, I know. NASA got men to the moon using slide rules and now with the great computers, clouds and technology they can't get a man on the international space station.
I loved electronics when you could design, build and understand the circuit but now most everything is a chip. Used to tape copper covered boards and etch off the unwanted copper to make circuit boards. Even considered being an electronics teacher but headed instead into 30 years in telecom.
I still use a flip phone and don't understand yet all that it can do. Once while sitting on the pot and fooling with the thing, it flashed. Unsure of what that meant or what it may have took a picture of...... I just set it by the sink and backed slowly out of the room, hoping someone would later explain it to me. I'm told the video can be viewed for a dollar thirty five cents a minute on the internet! Oops!! LOL
That's a good one, I think I'll save the $1.35. When I was a lot younger we lived on a party line. Our number was ring one two. If the guy down the road wanted to call he wouldn't have to go through the switch-board operator but cranked the handle on the side of the phone, one long turn and two short ones. Everyone on the party line heard one long ring and two short ones. You had to know what your ring was to know if the call was for you. You also new more than half the people on the line picked up just to listen to what you were saying and who called you. Not quite as old as the Jed Clampett and Granny, but close. Years later a friend, who is much more advanced technology wise than I, and I were driving out in the country when he missed a curve and we got stuck in a huge snow drift. He opened the door, went to the trunk and came back with what I thought was a suit case. He opened it and inside was a phone. It had a receiver and body just like a regular phone on a kitchen wall. Similar to attached. He used it to call for help. I thought that was the most fascinating piece of equipment ever made. Look at what they have and it can do now. Now I have a more modern phone with a receiver on a cradle and a long curly cord that attaches it to the part with the dial on it. Been thinking of getting one with a push button touch tone dial. Or maybe have kids so they can teach me how to use a cell phone, or, maybe not.
