car wont stop cranking

So this morning I went to start my 70 cougar. Fired right up but the starter was still engaged so I pulled the key out and it was still going. had to unplug the battery to make it stop. Replaced starter solenoid thinking maybe it was stuck and starter while I was at It. hooked the battery back up and went and turned the key and it still did it. My guess is I have a bad ignition switch???

Yes, ignition switch is the likely culprit.

too bad cant find those at autozone… .

The easy way to tell is that if you pull the wire off the S post on the side of the solenoid it will stop cranking if it is the switch. You didn’t by any chance add any kind of electronic ignition, high output coil, or modify the ignition in some way?

Check the solenoid first. 99.9% of the time, it’s the faulty component.


have petronix but have had for awhile. already replaced solenoid just down to the switch

Yeah–it’s the switch or the solenoid. The repro, cool-looking Autolite solenoids totally suck and will stick the very first time you use them (for real), so if you stuck one of those worthless things on, that could still be your issue…I go unoriginal-looking and use the Napa Gold/heavy duty solenoids. Also, make sure your engine ground strap to the firewall is good and solid; “they” say a weak ground will stick your solenoid. Of 4 cars I had this happen to, only 1 was due to the ignition switch. After the first time, when my battery cable was super tight and really hard to get off and my coil exploded, I installed a lever switch on the negative battery terminal of any old car I drive so I can kill the engine easily if this happens.

My '77 LTD would do the same thing. Every time it was the solenoid.

If you installed a high output coil it is pulling too much current through the switch and that will eventually cause the failure you have right now. If you just did the Ignitor it will have no effect at all on the switch.

Call Pertronix and tell them you have starter run on and they will send you a diode that you put in the ‘I’ wire at the solenoid. Or like I did after several solenoids and a starter back to points.

The I terminal is only hot when the starter is turning. It bypasses the resistor wire, providing 12 volts to the coil to produce a hotter spark while voltage is reduced by the load of the starter motor. Putting a diode in that lead would eliminate that function. It would be exactly the same as just unplugging the wire and leaving it unplugged. The diode from Pertronix is supposed to be used at the voltage regulator. Cars that use voltage comparison to illuminate the ALT or GEN warning light in the dash can in some cases pass enough current through the bulb to back flow to the coil feed wire to keep the car running. I have never seen that problem with a Cougar.

My Pertronix instructions said the same about the diode placement. Should be used at the voltage regulator if you have a run-on problem after installing.

also happens when a connection is over-tightened on the solenoid.

lol here is the kicker. Advanced auto actually gave me a bad starter solenoid with the exact problem as the one I gave them.