Car Ignition is still on when turning car off

[Duffman]

Hi, I have fried out some wiring on my 70 240Z when my line from my starter solenoid became unattached from my alternator while I was driving my car.  I burned up 6 wires in the engine bay, that I could see, and now when I turn my engine off, the car tries to start or run on as if it is still getting constant power through the ignition.  The emergency brake light is on in my gauge, as if ignition is still on, when the key is turned off.  I have replaced the burned wires in engine bay, had my alternator tested, replaced my ignition switch, replaced my starter relay, and I still have "run on" with the key turned off.  I am looking at everything I can to find the fault.  One area I was not sure about was the alternator diode plug, which I use for my internally regulated 60 amp alternator.  If I fried it and it is unable to work correctly, would that cause my symptoms?  I am not sure exactly how it works, so I may be grasping at straws, but thought it was worth asking to check it off the list.  Any other areas I should check, please let me know.

 

Thanks, Duffman

[Zed Head]

The plug and diode is a good guess.  Assume you have one of the MSA or Dave Irwin adapters?

The simple test would be to disconnect the T plug at the alternator, engine off, and see if the brake light goes off.  You can then also start the engine with the T plug disconnected and see if the engine turns off correctly.  It won't hurt to run on just battery power for a little while.

If that doesn't show the problem, then you might have a melted wire in a harness somewhere.

[Duffman]

Thanks, Zed Head, will give it a try.  Yes, I have one of Dave's adapters, well worth the money!

[Duffman]

Bummer, cut off plug to adapter, as it was stuck, did not make any difference with how car still shows power on. When I put key in ignition and just turn it slight, car tries to start before I get it to On position.

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[Duffman]

Am wondering if cutting off the wires to the plug defeats the purpose of the jumper wire as well as the diode, which would still create ignition on with key in off position? It was melted together, had to pry apart, which destroyed plug to adapter as well as adapter. Without jumper in place, irregardless of diode not in place, could I still have some issue? Need to buy new adaptor anyway, so will find out.


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[Duffman]

Anyone know which 2 wires are jumped in the alternator adapter that Dave makes?

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[Zed Head]

12 hours ago, duffman said:

When I put key in ignition and just turn it slight, car tries to start before I get it to On position.
 

Sounds like the electrical part of your ignition switch might be messed up.  You didn't mention this before though.  You implied that key action was normal.  If things change with each turn of the key maybe the switch is failing.  It can be unplugged also.  If the power goes off there's a short inside the switch component.

 

[Duffman]

Issue resolved, my new replacement alternator was bad, with 12v line going into the T fitting grounding out in the internal VR. Replaced my replacement and now all is good!

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[Duffman]

Sorry, didn't complete my thought! The reason my wires fried in the first place wasn't my line coming loose, it was a bad replacement alternator. I rewired around my alternator adapter plug and wired directly, following the instructions by woodworkerb.com. Everything works as it should!

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