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Went to turn 71 off last night and it kept running. Ign switch bad or getting feed back? Have HEI disttributor with MSD 6al box. Small red wire hooked to pink wire coming off ignition switch. Also have internal regulated alternator with 3-wire( wired as per instructions on TC) With switch off alt light was on and voltmeter went to zero. Has been working fine up until then. Just got car running and have been driving taking short trips with it while working on my oil leak bugs. I unhooked small red wire from box and motor shut off. Disconnected battery until I can find out what's happening. Any in-put would be appreciated. Thanks,Jim :confused::confused::confused:
 

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It could be a bad switch but try this. (If your car has a non-tilt column) Unbolt the two bolts that holds your column up. You will see your ign switch there attached by two bolts.(Might be phillps head cant remember) Take the switch down. Where the rod connects into your ign. switch there should be a black slide with a hole where the rod connects into. Place a screwdriver in that hole and slide it foward. The car should fire up. Then pull it back down to turn car off. If it turns off you just need to adjust your rod. If it doesnt turn off, your switch may be bad. If it does turn off turn the key to run, and place the rod back into the hole with the ign. switch slide one click away from start in the run postion. Place the switch back onto the column and slide bolts back into holes. Apply some pressure towards your steering wheel to ensure your rod is pulling it out of the start postion,and tighten the bolts. Then try your key again and see if it functions properly. This is all I could think to do hope it helps

Kade
 

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Discussion Starter · #3 ·
Kade, Thanks for the eply. I hooked the wire to ign back up and it started up today. I'll go ahead and drop column in the morning and do as you suggested. I think it must be there since I can unhook it at the ign and the motor dies. Thanks for the in-put. Jim
 

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Went to turn 71 off last night and it kept running. Ign switch bad or getting feed back? Have HEI disttributor with MSD 6al box. Small red wire hooked to pink wire coming off ignition switch. Also have internal regulated alternator with 3-wire( wired as per instructions on TC) With switch off alt light was on and voltmeter went to zero. Has been working fine up until then.
Its most likely getting feedback from the alt light. It takes very little power on the MSD small red to keep the 6al energized. You can add a diode to prevent the 6al from getting feedback. Taken from 6al instuctions..........

ENGINE RUN-ON
If your engine continues to run even when the ignition is turned Off you are experiencing
engine Run-On. This usually only occurs on older vehicles with an external voltage regulator.
Because the MSD receives power directly from the battery, it does not require much current
to keep the unit energized. If you are experiencing run-on, it is due to a small amount of
voltage going through the charging lamp indicator and feeding the small Red wire even if
the key is turned off.
Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the
parts bag. By installing this Diode in-line of the wire that goes to the Charging indicator, the
voltage is kept from entering the MSD. Figure 6 shows the proper installation for early Ford
and GM vehicles.
Note:Diodes are used to allow voltage to flow only one way. Make sure the Diode is installed
facing the proper direction (as shown in Figure 6).
Ford: Install the Diode inline to the wire going to the #1 terminal.
GM: Install the Diode in-line to the wire going to terminal #4.
Figure 6 Installing the Diode to fix Run-On.
GM 1973 - 1983 with Delcotron Alternators
GM Delcotron Alternators use an internal voltage regulator. Install the Diode in-line on the
smallest wire exiting the alternator (Figure 6). It is usually a Brown wire.

http://www.msdignition.com/pdf/6 series/6series.pdf
 

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Discussion Starter · #5 ·
Greg, Thanks for the information. Now that you mention it I remember something about that. I will look in the little bag of parts and find the msd directions. The way I wired the red wire it would be real easy to hide a on-off switch under the dash as a theft deterent. Would it work to just kill current going through the pink wire coming off the switch? Thanks for your help. I always read your excellent advise when you give it on TC. Jim
 

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The way I wired the red wire it would be real easy to hide a on-off switch under the dash as a theft deterent. Would it work to just kill current going through the pink wire coming off the switch? Thanks for your help. I always read your excellent advise when you give it on TC. Jim
Yes.
 

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Jim,
did you install the diode in the correct direction?
a diode is like a check valve.
only works in one direction.


david
 

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i have seen alternators do that as well, Jeff
 

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As a test, try disconnecting the 2 small wires from alt, start the car, then turn off. If it won't turn off then the problem is elsewhere. If problem is elsewhere, turn the key off and check to see if other things that shouldn't have power do (like wipers, radio, TS ect...)
 

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Discussion Starter · #12 ·
Greg, I unplugged the 2 wires and it shuts off. I double checked the wiring and it seems to be wired right. But, which wire am I supposed to put the diode in? The one to terminal #1 or #2? It's in the one to terminal #2 now which is hot all the time. Also according to my volt meter the alternator is putting out about 15 volts when running. Thanks, Jim
 

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Jim,

Do you happen to run an electric cooling fan? I had that same problem before and found that the electric cooling fan was backfeeding and caused the same issue.
 

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Greg, I unplugged the 2 wires and it shuts off. I double checked the wiring and it seems to be wired right. But, which wire am I supposed to put the diode in? The one to terminal #1 or #2? It's in the one to terminal #2 now which is hot all the time.
Terminal 1 (which only has power with key on). This wire actually comes from the ground side of the GEN lamp.

Also according to my volt meter the alternator is putting out about 15 volts when running. Thanks, Jim
Where did you measure this at? Put the diode on the correct wire and in correct position (which is stipe towards alt) then remeasure output voltage.
 

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Discussion Starter · #15 ·
Greg, Installed diode correctly and now working right. I was getting 15 volts across battery and also on gauge. Drove it a little and it came down to about 14.5. I guess I'll keep an eye on it and change alternator if it starts overcharging. Thanks for the help. Jim
 

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Had a 72 Chevelle years ago that wouldn't turn off. Come to find out it was just frayed wires at the starter touching the header.
 
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