genec728

About 2 months ago I tried starting my 66, 6 cylinder convertible after it had been sitting idle for about 3 months and when I turned the key to start it, the starter engaged but would not stop spinning even after turning the key to "off". I pulled the positive cable off the battery, and, of course, it stopped. I bought a new Motorcraft solenoid switch and installed it and it has started Ok until yesterday when it did the same thing with the 2 month old solenoid switch. I still had the old Motorcraft solenoid switch in my garage that I removed 2 months ago so I installed it back on the car and it's working fine. I've had this solenoid switch problem several times over the years and have bought and replaced a number of them. My ignition switch and the starter check out Ok so I am at a loss as to why these solenoids continue to give me problems. I would appreciate any and all ideas you might have on this problem. I'm afraid to drive the car away from home and have to restart it because the solenoid might fail again and leave me stranded.

racer_dave

Check your grounds. Clean the area on the firewall where the solenoid mounts, make sure the surface where the starter mounts is good and clean. Don't forget the ground strap from the motor to the chassis.

kenash

Hi,
I can see were this could be perplexing. I'm not sure how you can induce it to occur, but, it would be informative to see, if while the starter is still spinning (after the key is off), that you could tap on the solenoid. On the chance the starter contact side is not releasing. Or, the contacts within the ign. switch are deforming in some way
Also, when you say the ignition switch is "ok". How was this determined? You might revisit that aspect.
I think about the solenoid being nothing more that a "robust" relay. Knowing how they work you're dealing with contact points. They can fuse and stick closed.
There have been numerous reports of newly purchased solenoids failing. As know, these days, to increase the bottom line, so many of our mfgs. are going "off-shore". If those contractors are not ISO9001 certified, their quality control measures, they are cheaper for a reason...they use inferior materials!
Hope this offers a few nuggets for thought. Good Luck!

jlg2002

If the starter relay looses a ground the internal spring will open the contacts. (it is energized ON thru the S terminal) I would do the following to isolate:
pull the small wire off of the starter relay it should disengage for the reasons noted. if it does not give the relay a good whack with a small hammer. lastly, remove the wire off the relay that goes to the starter. if it doesn't it's definitely the starter.

Personally, I would suspect the starter Bendix is bad and not releasing after engine start.