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Active member
Sep 10, 2019
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My Car
73 mustang Mach 1 Q code
I have a 73 mach 1 with the Q code 351, when I go the start car it cranks but when I turn key off still cranks until I take battery cable off. When I connect battery it won’t crank until key is turned. Changed solenoid 3 different times and put new ignition switch in. Was wondering if i have a wire on wrong.everything is hooked up right to the solenoid as per diagrams. Any help would be appreciated
Could be your starter bendix is hanging up while cranking.
Just a thought here. Did you replace your ignition cylinder or ignition switch? The reason I’m asking is that the 73’s that were built late have a different shaped tip on the cylinder. The parts manuals say cars built after 5/14/73 have the new later models cylinder. My car was built on 5/21 and still had the pre-5/14 cylinder. I have no idea if this could be a contributor but with everything you’ve done something is keeping your 3 starter relays from dropping out?

Hopefully someone can help you out with this that knows more than me. Very interesting post

Are you using a stock starter or an after market starter? Some High torque after market starters have a solenoid built into the starter that may require they be electrically connected differently than a stock starter.
Take the R-LB wire - the one from the ignition to the starter motor relay - off. Check the voltage with a meter, turn the ignition to start and release to run, check the voltage again if it is hot it might be the one going to the coil. You might have the coil side and the start side reversed. As for the starter running after turning the ignition off...maybe the coil is discharging through the start solenoid.
Sounds like your ignition switch is not releasing. It's on your steering column behind the column cover. You can clean it out with electrical connection cleaner. Does your key switch spring back when you let it go or is it sticky? You may need to clean your key switch too. You will see a small rod coming from behind your main column that extends down toward your electrical switch that is screwed to the column. If you spray WD40 up towards the steering wheel and flip the key back and forth while you are spraying, you can eventually clean it up and loosen it.
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Thanks aces, yes I had replaced the key switch and no it does not spring back by its self. I’m going to take it out and clean it and try again
And as was mentioned will compare the old one with the new on to see if there’s a difference

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