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Topic: Ignition Switch, key cylinder, won't turn off

in Forum: C3 Electrical

Ignition Switch, key cylinder, won't turn off

Posted: 2/15/14 5:45pm Message 1 of 9
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Gordonvillle, TX - USA
Joined: 11/28/2003
Posts: 228
Vette(s): 1968 Roadster 427
I have got the new dash harness in place on my 68 and everything seems to work on a trial bases. I plugged in the gauges and lights and they all work and I will  finish putting in the console and passenger side dash.
 However I can start the car with the key, but I can't turn it off with the key. I pulled the key cylinder out and used a screw driver and turned the car over, but again could not get it to turn off. 
I have not disturbed the starter, so I don't think that is the problem. 
I ordered a new switch and cylinder and it does the same. So I don't think I have two bad switches. 
Could I have some bad connection at the fuse box, which lets the ignition start the car, but not letting it shut it off???????????  




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Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/15/14 9:59pm Message 2 of 9
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Carson City, NV - USA
Joined: 12/4/2013
Posts: 239
Vette(s): Numbers matching 1972 350 4 speed, silver pewter body with blue interior
I think your coil is getting juice 24/7. Any time you spin the engine it lights right? How do you turn it off? I'd use a multi meter to verify your coil is getting juice with the ignition switch in the off position. Then locate the mis match on the connection. Somewhere in your replacement wiring you have the ignition "run" lead (coil) attached to a continuous hot lead. Like you said, probably not 2 bad switches so this seems logical. This would also kill your battery and maybe cook your coil also if left on for hours at a time.


My Christmas present to ME! Bought Sat 11-30-2013. 72, 350 4 spd, Silver with blue interior...Can't you just hear Pablo Cruz playing in the background?

Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/16/14 5:07pm Message 3 of 9
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Gordonvillle, TX - USA
Joined: 11/28/2003
Posts: 228
Vette(s): 1968 Roadster 427
Thanks for the advise.  The coil was juiced all the time. On my stock wiring I connected a wire from the fuse box to the coil and automatic choke to come on hot when the ignition switch was turned on. 
On the new wiring harness I plugged this same wire into the fuse box but put it on a connection that is hot all the time. Once I reconnected the wire it all works fine. 
Thanks again for the heads up. 
I sure like this web site.
 The members have walked me through many problems in the past, and I am sure many to come. 




Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/17/14 11:07am Message 4 of 9
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Glad yo got it figured out, however.....I wouldn't recommend using the same power source for the ignition coil AND the choke heater coil. A problem with the choke could leave you stranded on the side of the road somewhere. Having the thwo powered by the same wire can also pull available voltage to the coil down, causing hard starts and such. Another problem would be that the coil does not need, nor does it like a full 12v all the time. Early cars used a resistor in the circuit to lower the operating voltage once the car was running, usually dropping it from 12v to around 6-8 volts. This keeps the coil AND the points happy. Thumbs Up


Joel Adams
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Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/20/14 4:22am Message 5 of 9
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Zachary, LA - USA
Joined: 1/27/2013
Posts: 201
Vette(s): 1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(
Adams' Apple said: I wouldn't recommend using the same power source for the ignition coil AND the choke heater coil. A problem with the choke could leave you stranded on the side of the road somewhere.


Great advice...  I did that exact same thing and need to go change it.  Maybe a relay?





"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner

Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/20/14 10:54am Message 6 of 9
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Relay....for whut? 
The '68-'74 cars have a resistor wire for the coil coming from the ignition switch, but the coil gets a full 12v from the starter while cranking, for quicker starts. After it starts, the 12 v from the starter is disconnected, and the resistor wire from the ign switch DROPS the voltage at the coil to around 6-8 volts Having the full 12v at the coil all the time will overheat the coil, and burn the points much quicker.
The voltage for the choke coil should be 12v anytime the key is on, until the choke fully opens. The choke coil voltage normally comes directly from the alternator, but.....the '68-'78(?) did NOT have an electric choke to begin with, so the wiring wasn't there for a choke coil. If you replace the carb with one that has the electric choke, you need to power it from somewhere....but using ignition coil power isn't the best way to do it.



Joel Adams
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Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/20/14 11:20pm Message 7 of 9
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Carson City, NV - USA
Joined: 12/4/2013
Posts: 239
Vette(s): Numbers matching 1972 350 4 speed, silver pewter body with blue interior
Joel, can you tell me the location of the ballast resistor? I have the MSD conversion ignition....I wonder if it requires the resistor? The PO had a shop install it. When I quickly turn the ignition off and turn the key to accessory power the engine continues to run. So someone wired it to an accessory hot lead. I would like to locate the OE coil lead and use....with or without the resistor as needed.
Dave


My Christmas present to ME! Bought Sat 11-30-2013. 72, 350 4 spd, Silver with blue interior...Can't you just hear Pablo Cruz playing in the background?

Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/21/14 5:36am Message 8 of 9
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
The resistor is the wire itself, not a separate item. The resistor wire goes to the coil from the ignition switch, and has a cloth-like covering on it....similar to the old, cloth covered wiring used in houses. If you do not have points, you prolly don't need a resistor, but I guess it would depend on the ignition manufacturer's recommendation.


Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: Ignition Switch, key cylinder, won't turn off

Posted: 2/21/14 8:00pm Message 9 of 9
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Former Member
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Zachary, LA - USA
Joined: 1/27/2013
Posts: 201
Vette(s): 1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(
Adams' Apple said: Relay....for whut? 
The '68-'74 cars have a resistor wire for the coil coming from the ignition switch,


When I redid the car, I swapped the harness for a '75 one so I could easily install an HEI ignition and electric tachometer.  But I tapped the choke directly into the ignition wire.  Your discussion made me rethink that.





"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner

in Forum: C3 Electrical


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