Jfsram

First mgmuscari now you. Stop guess or using a common problem as your guide.

This is pretty simple. Check for voltage at the small wire on the solenoid OR unplug the small wire while it's stuck cranking.

There should be no voltage there unless the key is in the start position AND the clutch pedal is down.

DRAGUL

wow getting expensive throwing parts at that problem? Just like JFsram said check at the relay. All you have to do is pull off the little wire on the side. Still cranks = bad relay and could also be bad starter causing relay to go bad. Stops cranking = short in ignition circuit

mgmuscari

Mine ultimately ended up being a short somewhere in the starter - after 3 relays, the starter engaged while I was doing about 3500 RPM's and accelerating. Needless to say, that unit was completely chewed up by the flywheel.

I replaced the starter and haven't had any more problems since.

wcinn3

So, pulling the small wire DID NOT stop the cranking. How do I differentiate between bad solenoid or starter? If it helps the diagnosis, I had no spark when it was cranking. This is actually a '69 302 (5.0L). Thanks!-Bill

84CopperGT

I had this happen on my 84 GT. I installed a spring loaded toggle in between the ignition and solenoid and never had an issue again. It also kept the car from being stolen when i lost the keys.

Jeremy Ball

Do not tighten the solenoid to body so tight with both screws. You’re putting the solenoid in a bind and causing it to stick. Been there done that, just try one screw if you can

wbrockstar

How Do I Differentiate Between Bad Solenoid Or Starter

Make sure the transmission is in neutral (5speed) park (auto).Use a long screwdriver and lay it against the two large posts on the starter solenoid.If the starter turns over fine,the starter and the starter cable are fine.If it doesnt turn over,the starter or cable is bad.
Now remove the red/blue wire from the small solenoid post,lay a long screwdriver across the small solenoid post and the large solenoid post that the positive battery cable is attached to.The starter should turn over.If it doesnt,the solenoid is bad.
If it does turn over,the solenoid is ok.

Another thing that'll cause the starter to stay engaged is low battery voltage.Reconnect the red/blue wire to the solenoid.Connect multimeter leads to the battery posts and turn the key on/engine off.The meter should read 12.5+ volts with a fully charged battery.Now keep the leads attached to the battery posts,disconnect the coil harness (disables the ignition) turn the key to start and watch the meter.The meter should read 9.5+ volts during crank mode.If voltage is lower than this,that'll cause a clicking solenoid,
slow cranking or solenoid contacts that weld themselves together.

If the starter stays engaged when you turn the key to start then release it to run,the solenoid contacts have welded themselves together.To unstick the contacts,disconnect the battery cable,pull the solenoid away from the fender apron then smack the back of it with a rubber mallet.This will normally free the contacts.