[800XCR]

So I installed a new mini starter and just coiled up the purple wire as it went to the S terminal on the old starter. Also running MSD 6A box. Starts just fine, but doesn't shut off with the key. I have to turn the key off and unplug the alternator to shut the engine off. Obviously the purple wire is tied to the alternator somewhere to shut down the voltage when the key is turned off. Do I need to install a new on/off switch or can I piggy back the purple wire somewhere and if so, where?

Thanks for the help!

 

[Slowpoke70]

Purple should still go to S.

What wires do you have going to the starter now?

MSD 6A should have:

Large RED wire wired to the large positive terminal on the starter (same one as the cable from the battery)

Large BLACK grounded to the engine and/or chassis. It can be grounded to the ground post on the starter if the wire will reach, depending on the location of the MSD box.

Nothing else from the MSD should be wired to the starter.

I realize that mini-starters don't come with an S and R terminal, since they're basically late-model GM starters and an "R" terminal wouldn't be necessary to power the points ignition which was no longer used by GM by the time the new starters were introduced.

So the wire that needs to be "coiled up" near the starter should be a YELLOW wire.

What wire IS CURRENTLY hooked up the S terminal on your mini starter?

 

[Slowpoke70]

To clarify things a bit:

The function of the PURPLE wire is to provide 12v to the S terminal ONLY when the ignition switch (lock cylinder) is turned to the the START position. When the lock cylinder is in the position, a rod connected to it pushes on the multi-position switch located further down the column. This switch, and not the lock cylinder itself, is what determines the "ACC, LOCK/OFF, RUN, START" functions. The purple wire carries 12v ONLY when the lock cylinder is turned to the START position.

Inside the multi-position switch mounted to the column, is a small return spring that pushes the lock cylinder back to the "RUN" position when you release it after the engine starts, at which time the PURPLE will no longer provide 12v to the S terminal, thus the Solenoid is no longer active.

 

[Slowpoke70]

Also, what is the SMALLER RED wire from the MSD box wired to? It should be wired to a "SWITCHED 12V" that is only "hot" with the lock cylinder in the "START and RUN" positions. I typically use the wire that was originally attached to the positive side of the Ignition Coil. This will typically be a "cloth covered" WHITE wire on Chevelles originally equipped with points ignitions. On later model HEI-equipped GM's it will be a large gauge PINK wire - many older GM's have been upgraded to HEI - some of them with the correct PINK wire if person performing the upgrade decided to stick with GM's color coding.

 

[800XCR]

I have the yellow wire hooked up to the small terminal on the starter, are you saying it should be the purple wire?

 

[O'Man]

So I installed a new mini starter and just coiled up the purple wire as it went to the S terminal on the old starter. Also running MSD 6A box. Starts just fine, but doesn't shut off with the key. I have to turn the key off and unplug the alternator to shut the engine off. Obviously the purple wire is tied to the alternator somewhere to shut down the voltage when the key is turned off. Do I need to install a new on/off switch or can I piggy back the purple wire somewhere and if so, where?

Thanks for the help!

Something is screwed in your wiring. Even when the wiring is right some cars "run on". You might need a diode in the circuit to prevent back feeding juice. See MSD instructions. Back feeding can send enough juice to the ign while the engine is spinning down (after the key is off) to fire the ign. The engine runs a second because the ign stays on for a second...the engine runs...the alt sends more juice, the engine runs, the alt sends more juice...the systems goes "open loop" and can't stop running. Disconnecting your alt is taking away the voltage source ( the alt) that is backfeeding the ign. The diode prevents this. Get your wiring squared away and then look at the MSD paperwork on "diodes".

 

[VinceS427bb]

I have the yellow wire hooked up to the small terminal on the starter, are you saying it should be the purple wire?

yes, purple to the small terminal
yellow wire unhooked and not used...:thumbsup:

 

[Georgia69]

Go back and read the instructions that came with your MSD 6A. There is a diode that needs to be installed in one of the wires (I forget which one) or the engine won't shut off when you turn the key off. Went through this on my truck with MSD 6A.

 

[Georgia69]

See here........

http://www.chevelles.com/forums/showthread.php?t=294736

A little more here....

https://www.msdignition.com/forum/showthread.php?t=3186

 

[67SCOTT]

I had the same MSD run on issue with mine. But mine would do it ocassionally. I found if I turned on my headlights, then turn the ignition off, the engine would shut off.

Scott

 

[800XCR]

Ok update.....I do have the purple wire on the starter. All appears as it should, it has to be backfeeding somewhere. I will pick up a diode and see if that resolves it. I have tried using multiple keyed wires including a new jump wire running through or to anything else with the same results.