need help finding a wire

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coreyg

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So I have a 71 plymouth scamp. I need a wire that is both hot with key on and in the cranking position. I've multi metered every wire coming from the ignition and non fit the bill.
 
THERE IS NO SUCH wire. Remember that the ignition switch is the ultimate source, the "headwaters" as it were, for switched power. All you have is

1...Accessory, which is hot in "acc" and in "run." It goes dead in "start."
2...IGN1 or "ignition run." Hot ONLY in run, it goes dead in "start."
3...IGN2 or "bypass" (brown). This is what supplies ignition voltage to the coil during cranking. Hot ONLY in "start" and it is a SEPARATE switch contact from the yellow "start" wire
4...."Start" normally yellow.....hot only in "start" feeds power to the starter relay

Tell us more about what you are doing. If you still run an ignition requiring a ballast resistor, you might be able to use to large rectifier diodes, run them off "ign1" and Ign2" and tie them together

You could also do this with a relay.

If you change to an ignition not requiring a ballast, just tie ign1 and ign2 together

Here is how diodes would work:

Steering Diode.jpg


The "load" would be whatever you are trying to power. The diodes must be large enough to handle the power from the load. V1 would attach to the IGN1 terminal of the switch, and V2 would attach to the IGN2 terminal

If you don't have large enough diodes, or what to do so, you can use two smaller diodes to trigger a relay coil at the "load." Then wire up the relay contacts to supply the load your are connecting
 
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What do you need it for? It sounds like you want the wire to be hot while cranking. I can't think of a reason for what you are wanting. If you let us know, it would help us to help you.
 
cigar lighter.....? How about black off the flasher or horn relay. I dont know if there is a switched lead that is on under both modes.
 
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I'm doing a genIII hemi swap and the mega squirt requires a feed that is hot with key on and cranking.
 
I'm doing a genIII hemi swap and the mega squirt requires a feed that is hot with key on and cranking.

Next question..........what are you using for ignition "I'm assuming" you do NOT need a ballast resistor. IF not just tie ign1/ ign2 together and go for it.........covered in post 4^^
 
With EFI, it would be best to do more than just tap into the original electrical system.
A circuit using a relay or two and auxillery fuse box is worth looking into. Consider including a direct battery feed/charge wire.
 
Next question..........what are you using for ignition "I'm assuming" you do NOT need a ballast resistor. IF not just tie ign1/ ign2 together and go for it.........covered in post 4^^

AND ign1 and 2 are easily found right where the ballast used to be, and finding each with a regular test light is easy enough.
Ign1 and 2 are separate contacts inside the ignition switch so tying them together under the hood will not back feed or short to anything else, so no diodes needed.

This is the way we set up our HEI kits because they need a full 12v when cranking and running both.

I wrote this for the OP Del, as I know you know this.:D
 
I'm pretty sure Ign2 (brown) is what you want.


Alan

That's one of them, but he needs both tied together (1&2) so he has power in cranking and run both. (with a factory electrical setup anyway)

diagram.jpg
 
That's one of them, but he needs both tied together (1&2) so he has power in cranking and run both. (with a factory electrical setup anyway)

View attachment 1715251067
Huh I'm pretty sure I tested that on and it lost volts in the crank position. I just decided to get a push button start which will give me the wire I need.
 
Huh I'm pretty sure I tested that on and it lost volts in the crank position. I just decided to get a push button start which will give me the wire I need.

You should not need to. Re-read my post. If ign2 is not hot in cranking, either the key switch is bad, or you have a wiring problem. The car should have never started "on the key" because IGN2 is the ONLY source of power to the coil/ ignition during cranking

Lots of guys have done this. I had Holley HP EFI on my Dart before I tore it down and it worked just fine that way. At the time I was using a GM HEI module for ignition
 
You should not need to. Re-read my post. If ign2 is not hot in cranking, either the key switch is bad, or you have a wiring problem. The car should have never started "on the key" because IGN2 is the ONLY source of power to the coil/ ignition during cranking

Lots of guys have done this. I had Holley HP EFI on my Dart before I tore it down and it worked just fine that way. At the time I was using a GM HEI module for ignition
Something must be wrong with my ignition cause the brown wire goes dead during cranking. I tried the relay there seems to be a small dead spot when going from key on to crank when the relay switches over. I wanted to do a key fab anyway guess now is the time.
 
Something must be wrong with my ignition cause the brown wire goes dead during cranking. I tried the relay there seems to be a small dead spot when going from key on to crank when the relay switches over. I wanted to do a key fab anyway guess now is the time.
Yeah we've seen a few threads about a misfire or even a backfire caused by the dead spot in transition from crank circuit to run circuit. I have no idea how they cured it. A separate toggle from a hot at all times like lighter/horn circuit to power ignition would be the simplest fix but you would need to remember turn it on/off. Goof luck with it.
 
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