Author Topic: Advice needed - ignition key fails to turn engine off in '67  (Read 731 times)

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Offline 67FBGT

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Advice needed - ignition key fails to turn engine off in '67
« on: December 31, 2017, 09:10:36 PM »
As per Subject.
My '67 has been parked up for some time. Put fresh 98 in it today, after a bit of cranking it fired up so I ran it up in the garage for several minutes until it was hot.
When I came to switch it off the key returned to Off and extracted but the engine just kept running; so leapt out and disconnected the negative cable to the battery and that stopped it.
So let it rest then tried it again, same deal.
Sorry if a silly question, but is this symptomatic of a worn out ignition switch? It's the original component. Or some kind of 'running on' issue perhaps; this is a first for me, haven't struck this before. The car is a bit smokey, would benefit from a good professional tune up I suspect.

Offline GEOFF289

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #1 on: January 01, 2018, 08:42:12 AM »
If its been parked up for a while maybe it just wanted to go for a drive....

Sounds like a dodgy ignition switch to me.

Offline Clubman7

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #2 on: January 01, 2018, 09:12:54 AM »
Or the starter solenoid is sticking.

Offline GEOFF289

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #3 on: January 01, 2018, 10:52:26 AM »
Wouldn't the starter remain engaged if the solenoid was sticking?

Offline Clubman7

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #4 on: January 01, 2018, 11:03:21 AM »
Solenoid also supplies power to coil.
If the contact for this is sticking , the engine will not shut off.

Offline shaunp

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #5 on: January 01, 2018, 11:07:57 AM »
does it run an MSD box, ?

Offline 67FBGT

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #6 on: January 01, 2018, 11:27:27 AM »
As the engine just keeps running and not stuttering and running rough, I presume it's not a case of 'dieseling' that I have read about. Although the car would undoubtedly benefit from a professional tune-up not to mention a good run. I suspect it's running rich as it's smoky out back, so will check the plug colour.

It has a Pertronix Ignitor electronic ignition module in it.
I have a brand new spare starter solenoid so can substitute to investigate that possibility.
The ignition switch doesn't feel smooth, it's quite a clunky 'click click' to operate, and it is old, so I am suspicious about it.

Thanks for the input, will investigate further today.

Happy New Year to everyone!

Offline evan

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #7 on: January 01, 2018, 02:11:20 PM »
My money's on the ignition switch. Try disconnecting the ignition wire near the switch (pink?) while the engine is running (faulty state). If it stalls, that would suggest that the ignition wire was live.
You could also try wiggling/tapping the ignition switch in hope that the engine stalls. If that works, change the switch.

Evan.

Offline Sundance Kid

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #8 on: January 01, 2018, 04:46:50 PM »
hi  does starter kept running on / had this problem on a 67 fastback and 70 boss . checked everything turned out solenold was sticking making contact internally brass tab both had similar problem , worked fine then one day ..F!?/!!!  ...etc mostures gets in or they arch out !!! orginials and correct autolite one they have a little vent at bottom of base plate . cheers Happy new year ..hi i can send u a pic of one i stripped apart to show u problem . solenold s ..brass / copper  internals etc
1970 boss 302 mustang

Offline 67FBGT

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #9 on: January 01, 2018, 10:25:48 PM »
Thanks everyone for all your suggestions and advice. I didn't get to the car today, being school holidays and all that that entails.

Hopefully tomorrow, will check the ignition switch 'pink' wire - excellent suggestion, thanks Evan.
And can substitute another solenoid. The one in the car is a generic item, I have a couple of spares both new and used. Haven't noticed if there's a little vent in the base plate. No the starter itself disconnects OK; the motor was started and run up to temperature in the garage, first time in many months, but then wouldn't switch off until I disconnected the battery (my rather panicky solution, being auto I didn't know how else to stop it as no manual clutch to ease out to stall it). Cheers SK.
Thanks all. Fingers crossed.

Offline 67FBGT

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Re: Advice needed - ignition key fails to turn engine off in '67
« Reply #10 on: January 03, 2018, 07:45:25 PM »
Fired the car up today, several times, and found that now the key works as it should. Bloody electrical gremlins.  :thud:
Still, thanks to your input I am ready for it next time it happens, perhaps it is a heat thing as I didn't run the car up to hot this time.

 

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