# Ignition switch problem or other



## woolsey10 (Oct 18, 2011)

I just finished a complete rewire on my 66 Lemans. When trying to fire it up the engine starts but as soon as I let off the key it dies. I know there are some other posts about this but I read them all and none of them have what I'm looking for. The engine is a Pontiac 400, it has hei and no balast resistor. I did a little research and found that I needed a wire from the R terminal on my solenoid to the coil terminal on the distributor. So I pulled the ignition wire from the coil and doubled up that wire and the new 12 gauge wire on the solenoid and reconnected to the coil on the distributor and tried to fire it up again and the same problem persists. I'm starting to think it is my ignition switch, although it was fine when I took the whole car apart for restoration about 5 years ago. If this is the case could I replace the ignition lock cylinder or would I have to buy a whole new switch? I'm sure the switch housing is fine since everything electrical on it is working as it should. Does anyone agree that it could be the switch, are there other things to look at etc.? Also how would I go about replacing the lock cylinder if that ends up being what I have to do? Thank you everyone!


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## PontiacJim (Dec 29, 2012)

Not sure where the thinking started in hooking up the HEI to the "R" terminal on a Pontiac solenoid. That's your problem. The "R" terminal is ONLY activated when you first crank the engine. As soon as you snap the key back, power is disconnected, engine dies.

Just to test, run a jumper wire from the battery to the +/power side of th coil and when you fire it up, see if it continues to run. Pull the wire off, and it'll quit.

You do need 12Volts going to the HEI. Factory points uses a resistor wire to drop voltage so the points do not burn. You can run a wire directly off the ignition switch or simply add a toggle switch under the dash wired for 12V to the coil. 

If you do a search in the *Google Custom Search* engine in the upper right, you should find a few threads on just this problem and how it was solved. :thumbsup:


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## woolsey10 (Oct 18, 2011)

I am getting 12v to the hei through the ignition coil wire at the fuse box. I found an article on americanautowire.com that talked about converting from a points distributor to hei and one of the things it mentions is an override wire from the solenoid R terminal to the coil terminal doubled up with the 12v feed wire. So that is where that came from. So I figured I'd try it since the engine won't keep running the way it was. But it did not solve anything, now I'm here.


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## BLK69JUDGE (Jun 10, 2010)

*x2*

what Jim said


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## woolsey10 (Oct 18, 2011)

Well do you have a link to such threads because I don't see them?


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## BLK69JUDGE (Jun 10, 2010)

call me I will help

2 zero 6 465 9165

Scott


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## PontiacJim (Dec 29, 2012)

woolsey10 said:


> Well do you have a link to such threads because I don't see them?


If you do a search for "ignition switch" you can find a few that relate to your situation. I assume you have a wiring diagram for your car. If I am correct from what I read, you should have had 2 wires going to the coil+ side - one is the cloth covered resistor wire which works in the "Run" position of the key and reduces 12Volts down to about 9Volts so as not to burn up the points, while the other wire is the 12Volt power wire which works when you turn the key to the "Start" position to give the coil full 12Volts for better starting. 

As soon as you snap the key back to the "Run" position, the 12Volt wire is disconnected at the key switch and the engine now runs off the resistor wire which is also connected to the key switch. The "R" terminal on the solenoid does the same thing that the 12Volt wire does which comes off the key switch - and when you snap the key to the "Run" position, the 12Volts is disconnected at the "R" terminal.

That said, you want to trace the wire from your ignition switch using your wiring diagram (or use a test light to determine which terminal is the "Run" position) and use this to hook to the HEI. You could keep the wire you now have from the "R" terminal going to the HEI as your "Start" wire as it would function just like the "Start" wire normally used by the ignition switch. However, you want to eliminate the resistor wire that would normally be used on the 1966 points distributor which you have replaced with the HEI. In its place, just run a wire from the ignition switch "RUN" position to the HEI. 

Some will remove the resistor wire at the firewall junction block  and replace it (engine compartment side) with a 14 gauge copper wire at that point going to the coil to give you 12Volts. Personally, I think it easier to go from the ignition switch directly to the HEI, but if you wanted it to look original, then replace the length of wire at the firewall junction block to the HEI.


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## woolsey10 (Oct 18, 2011)

Thanks everyone. It's been a few weeks and I've been busy with other things but I got the issue taken care of. Like jim said I ran a wire from ign1 on switch to the coil and now it runs as should. Just curious, should I install an inline fuse on that wire or just leave it the way it is? Thanks again all!


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## PontiacJim (Dec 29, 2012)

woolsey10 said:


> Thanks everyone. It's been a few weeks and I've been busy with other things but I got the issue taken care of. Like jim said I ran a wire from ign1 on switch to the coil and now it runs as should. Just curious, should I install an inline fuse on that wire or just leave it the way it is? Thanks again all!


Hooray! Success in getting it sorted out. I would not bother with an inline fuse. I would think that the main 12V power wire that energizes the ignition switch is already tied into the fuse block. :thumbsup:


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## oki_namiinori (Dec 29, 2019)

PontiacJim said:


> If you do a search for "ignition switch" you can find a few that relate to your situation. I assume you have a wiring diagram for your car. If I am correct from what I read, you should have had 2 wires going to the coil+ side - one is the cloth covered resistor wire which works in the "Run" position of the key and reduces 12Volts down to about 9Volts so as not to burn up the points, while the other wire is the 12Volt power wire which works when you turn the key to the "Start" position to give the coil full 12Volts for better starting.
> 
> As soon as you snap the key back to the "Run" position, the 12Volt wire is disconnected at the key switch and the engine now runs off the resistor wire which is also connected to the key switch. The "R" terminal on the solenoid does the same thing that the 12Volt wire does which comes off the key switch - and when you snap the key to the "Run" position, the 12Volts is disconnected at the "R" terminal.
> 
> ...



Searching through the theads I saw @PontiacJim explanation of the two wires to the ignition coil + side. I have 66 GTO with a Molly 28675 coil. Unfortunately, though brief (less than 20 seconds), I had an engine fire. Looked to be mostly black smoke damage. I have now found that the pink-clothed covered wire (possibly resistor wire) is hot to the touch while the engine is running. The pink cloth wire is also deteriorated. I was thinking of replacing the harness from firewall. Could I just replace the pink-clothed wire?

The remaining wire in the engine bay seems fine.


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## PontiacJim (Dec 29, 2012)

oki_namiinori said:


> Searching through the theads I saw @PontiacJim explanation of the two wires to the ignition coil + side. I have 66 GTO with a Molly 28675 coil. Unfortunately, though brief (less than 20 seconds), I had an engine fire. Looked to be mostly black smoke damage. I have now found that the pink-clothed covered wire (possibly resistor wire) is hot to the touch while the engine is running. The pink cloth wire is also deteriorated. I was thinking of replacing the harness from firewall. Could I just replace the pink-clothed wire?
> 
> The remaining wire in the engine bay seems fine.


Yes, the cloth covered wire should be the resistor wire and it will be hot to the touch. You could replace just the resistor wire, but it does not appear that there is anything available reproduced. So your option would be to use one form an old wiring harness and change it out.

You could purchase just a factory reproduction engine wiring harness for your car which should have the resistor wire

The other option is a straight wire, 12V, going to a ballast resistor block like used on other makes, and then to the coil. Not original and you would have to mount it on the firewall - it too will get warm.


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## oki_namiinori (Dec 29, 2019)

PontiacJim said:


> Yes, the cloth covered wire should be the resistor wire and it will be hot to the touch. You could replace just the resistor wire, but it does not appear that there is anything available reproduced. So your option would be to use one form an old wiring harness and change it out.
> 
> You could purchase just a factory reproduction engine wiring harness for your car which should have the resistor wire
> 
> The other option is a straight wire, 12V, going to a ballast resistor block like used on other makes, and then to the coil. Not original and you would have to mount it on the firewall - it too will get warm.


Thanks @PontiacJim 
What resistance is the ballast? Or do I just buy an RU11 standard ballast?


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## PontiacJim (Dec 29, 2012)

oki_namiinori said:


> Thanks @PontiacJim
> What resistance is the ballast? Or do I just buy an RU11 standard ballast?


There are several and the RU11 may be the correct one. I saw RU4 having a 1.3-1.4 Ohms and the RU10 shows to be 1.77-1.87 was also close to RU11 @ 1.75 Ohms.

The ballast resistor should be matched to the coil - the ohms resistance of the resistor and the coil primary winding should be the same or close. Measure the ohms at the coil between the + and - terminals, then find a ballast resistor with the ohm value to match the coil. Too high resistance and you reduce spark output, too low you'll burn up the coil.

So I would do the coil test and then see what ballast resistor you need. Generally GM resistance seems to be about 1.5-1.7 from what I read, but there are different resistances built into a coil.

Here is a good write-up and explanation that can help you get the correct ballast resistor to match your coil.

https://www.gomog.com/allmorgan/coiltest.htm


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## jmd55 (Oct 30, 2021)

hi i just had trouble been driving my 66 gto with hei for the 2 years i have had it done yesterday it shut off at a red light i had to hold the key on start to get home if i let go it died i have had 3 switches from ames in 2 years so i am guessing switch again i ran a jumper from battery to in cap coil started it and checked the dist plug and had 12 volts with it running any one have better luck with a switch from someone else


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