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Amc Gremlin igntion coil wiring

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Lollo54 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lollo54 Quote  Post ReplyReply Direct Link To This Post Topic: Amc Gremlin igntion coil wiring
    Posted: May/27/2023 at 3:40pm
Hey all AMC fans

Ive been working on a 74 gremlin now for a couple of months and sling the finishing things to make the electrical part work since it seems a lot is not correct. My coil is very hot after a short time, therefor i want my ballast resistor to work.
I was going to wire the ballast resistor but could not get my head around how bad the wiring diagram is that you find online for the gremmies. I am now wonderng how im going to wire the cables from my starter solenoid and from my voltage regulator to my ballast resistor and coil.

Should i wire direct from the stater solenoid to the plus side of the coil or to the ballast resistor

Can someone Help me with this?
Its for a 74 gremlin with 304. 

Thanks
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BassBoat View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BassBoat Quote  Post ReplyReply Direct Link To This Post Posted: May/27/2023 at 9:00pm
With normal running, you should read maybe 8 volts at the coil positive terminal.  Normal ignition wire should be either a resistance wire in the harness, or a separate ballast resistor if you bypass the factory harness.
When the starter is engaged, the iGN terminal on the solenoid should power 12-13 Volts to the coil positive terminal, bypassing the ballast or resistance wire.  This gives hotter spark temporarily to help starting.  
My car is older, and I run points, so there may be some things I missed if you have a more modern ignition.
Good luck!
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Lollo54 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lollo54 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/03/2023 at 2:20pm
Hello again 

Thought i figured it out but have not.
The wire reading 12v going from the I on the starter relay through a 1.5 Ohm ballast resisitor reads 5,2 volt at the positive side of the coil when having the key on the ON postition. Which seems low. Some say it Should read 6 and some 8. I have no idea what i should read. Does the coil get 12v when cranking automaticly and bypassing by itself?, or from where should i take 12v only when cranking?. Beacuse if i wire it directly from the S on the starter relay it keeps cranking until i unhook the wire,, obviously… beacuse the I and S connects 

Its seems like a easy problem but i wont figure it out, the wiring diagram on coil wiring all seems to be unclear.

Anyone having an idea or can show how they made on their gremlin??

/Adam 
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Heavy 488 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/03/2023 at 2:42pm
Voltage at the coil will vary depending if the points are open or closed at the time
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troutwilly View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote troutwilly Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2023 at 12:41am
Was or is the car running?  What makes you think the coil is too hot?  Have you used a laser temperature sensor to test its temp after running for a bit?
If you google "how hot does an automobile coil get" the first answer is 200*.  I wouldn't touch that.

On to wiring.  DO NOT hook a wire from the coil to the "S" terminal on the starter solenoid because when your ignition key returns to "run" from "start" you will be feeding power to the "S" terminal from the coil and your starter will never stop turning until you move the key off of "run".  Oh, you found that out.

As explained, the "I" terminal gets 12 volts when the key is turned to "start."  This 12 volts goes directly to the coil for extra power.  Once the key is released from "start" and settles in the "on" position, power goes to the coil from the fuse panel (usually) through a ballast resistor to cut voltage down a bit.

If you want to verify everything is working correctly get a helper to start and stop the car.  Put a volt meter on the coil and watch the voltage when cranking (pull the coil wire off the coil so it won't start) and when running.
Bill O.
70 AMX
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Lollo54 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lollo54 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2023 at 2:21pm
Thanks for sharing tour knowledge,
So i measured it today, when the ignition is on i get 5.2 volt and when cranking i get 8.5 volt, too low when cranking of it should be near 12.

As i said earlier it is only One cable going to the coil via a ballast resisitor from the I on the starter relay.

Battery is fully charged and have good voltage….
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