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Topic: Funny starting

in Forum: C3 Electrical


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Re: Funny starting (8/18)
 6/21/17 5:16pm
Ronnie71
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Smethport, PA - USA

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The starter solenoid checks out.  Going to replace the ignition switch next.

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Re: Funny starting (9/18)
 6/26/17 10:04pm
stingrayjim jrLifetime Member
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Ummm, before getting into the ignition switch,  double check the wires I circled in red on the schematic.... you'll see one coming off the solenoid, the other splicing into it just at the coil....  the one splicing in from the firewall(key switch) is hot when the key is on, the other wire coming off the solenoid is hot when you turn the motor over....so if the solenoid is good, there will be 12 volts when you activate the solenoid(turning the engine over) then the other wire is hot when the switch is in RUN position....  if the wire is hot(12 volts) with the key on, then more than likely the key switch is ok, in this instance....    might check the wire at the solenoid with key in Run and see if 12 volts is read at the wire there.... basically checking to see if its a broken wire....  


Modified diagram

(large diagram modified to link-aapple)





|UPDATED|6/26/2017 7:04:53 PM (AZT)|/UPDATED|


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Re: Funny starting (10/18)
 6/25/17 8:48pm
Ronnie71
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Thanks.  I have 12 volts on the wire to the coil in the run position and 12v at the solenoid "s" terminal when the key is in the start position.  I'm pretty sure it's a bad ignition switch. I've got a new switch but changing it will require dropping the steering column so I'm waiting for a rainy day to take this on.

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Re: Funny starting (11/18)
 6/25/17 11:32pm
stingrayjim jrLifetime Member
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SHELBYVILLE, TN - USA

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1978 L82 4speed

1994 LT1 6speed


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then,if you have 12 volts with the key in start at the S terminal, the wire going back up to the distributor is probably broken.... the wire coming off the solenoid is tied into the hot wire coming off the fuse block that goes to the distributor.... so there is a constant 12 volts going.  

Unless I am mis-understanding something here, it sounds more like the wire coming off the solenoid going to the dist that has issues.... broken wire or bad crimp on the end..... if the key switch works turning over the engine, then i would think its good...



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Re: Funny starting (12/18)
 6/26/17 10:23pm
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This being a '71 car, the original coil power from the ignition switch will be a resistor wire, which will drop the voltage from 12v down to about 8-9v...not enough to operate the coil on an HEI set-up. In order to have voltage to start the engine at the coil while cranking, it uses a full battery voltage(12v) source from the starter solenoid "I" terminal, which is the outside terminal of the solenoid.

Any terminal on the fusebox marked "Ign" will ONLY be hot with the key in the "Run" position, so there will be no voltage on that terminal while cranking. It starts when you release the key because voltage is now on that terminal.
You should, as Jimmie points out, and you confirmed, have 12v on the wire coming from the "I" terminal on the solenoid while cranking ONLY. In order for your set-up to work properly, you need to have BOTH wires, "I" from starter solenoid AND the wire from "IGN" terminal on fusebox connected on the "Batt" terminal of the HEI coil/dist cap. This will give you 12v while cranking(from the solenoid) and 12v in the "Run" position(from the fusebox).
Your ignition switch is not causing the problem, since you do have 12v on the "Ign" terminal with the key on.
hth  Thumbs Up



The "S" terminal at the solenoid is 12v coming from the ign switch to CRANK the engine...there will be NO voltage on that terminal in any key position EXCEPT while cranking. The "S" terminal is the small terminal closest to the engine block, and will be a larger diameter purple wire.


|UPDATED|6/26/2017 7:23:31 PM (AZT)|/UPDATED|


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Re: Funny starting (13/18)
 6/27/17 2:55am
stingrayjim jrLifetime Member
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Ooops, forgot about there being a resistor..... ok, must admit, i didn't realize there was a resistor.   Although he was getting 0 volts while its turning over makes me think the wire is either broken, or if there is a resistor, it might be disconnected or blown....guess if it were me and could not trace the wire, i would be compelled to run a hot wire to a momentary switch and splice it into the hot wire off the key switch... yeah i know,  me bubba...you jane... :)  but then i could at least drive and pick up a milkshake ... or banana split... onion rings... great, i'm hungry now... 

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StingrayJim
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Re: Funny starting (14/18)
 6/27/17 8:59am
Adams' AppleLifetime Member
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It's all in the details, Jimmie. Thumbs Up
In the original post, he states that he has 12v to the HEI from an "Ign" terminal on the fusebox, so that means he is not using the original resistor wire for the coil feed, but has run another wire from the fusebox to the distributor....at least that's how I read it. As I pointed out, the "Ign" terminals) on the fusebox are only hot with the key in the "On" or "Run" position....not while cranking. Also, the label "Ign" on the fusebox doesn't mean those terminals are for the ignition system, but simply meant to say that those terminals are only hot with the ignition switch ON....otherwise they are dead, power-wise. He will need to have the two wires (from "I" on solenoid and "Ign" on fusebox) tied together somewhere to make this work. Both wires will not be hot at the same time, so no issues there with backfeed.
The only other way to make it work is to find a terminal on the fusebox that is hot in both "Run" and "crank" modes.....which would have to be something in the lighting, or horn circuits. Smile



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Joel Adams
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Re: Funny starting (15/18)
 6/30/17 8:29am
nosal1
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Good Morning It sounds like you still have the 8' ressister wire in service that was used for a points system relative to OEM points system.You will have to run a separate 12 gauge RED wire from IGN post on fuse block to BAT side of HEI distributor.If you still have a yellow wire then disconnect this as it will go down to the R side of solinoid and will not be needed. God Luck      nosal

Re: Funny starting (16/18)
 7/1/17 8:15pm
Ronnie71
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Oh man! I should have checked the blog this am BEFORE I dropped the steering column and installed a new ignition switch which, as Adam explained, is not the issue.  Thanks for clearing up the fact that I need to patch a wire to the "I" terminal to get 12v to the distributor in "start". At least I now know how to change out my steering column....maybe I should upgrade to a T&T while I'm at it. :-)

update:  patched a jumper wire between the "I" terminal on the starter solenoid and battery input wire to the coil/distributor.  Started on the first roll!  Problem solved!  Now to put it all back together.  Thanks everyone for your help.  C3VR is awesome!!


|UPDATED|7/1/2017 5:15:28 PM (AZT)|/UPDATED|


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Re: Funny starting (17/18)
 7/2/17 10:52am
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 Clap  Thumbs Up

Glad to hear ya got it goin!!


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Joel Adams
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Re: Funny starting (18/18)
 7/2/17 5:44pm
stingrayjim jrLifetime Member
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SHELBYVILLE, TN - USA

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yippee!!  :)  

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StingrayJim
NCM Lifetime Member #1936

Stingray's '76���������������������������� StingrayJr's '78���������������������������Lil Red '94

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