Im having ignition problems. I have changed the starter twice and the solenoid twice. It starts fine when cold, but after running it, sometimes it will not crank after I turn it off. I will turn it off and try to restart it and nothing, it wont even turn over. I have even left the key in the "On" position and tried to jump it with a screwdriver from the starter, but the starter wont engage. I can hear the starter wheel spinning but it wont jump to the flywheel. Anyone out there with the fix?

 

I'm presuming you have a 7.3 diesel engine.
Those starters are pretty good and I have seen them deliver good service, but a lot depends on who rebuilt it.
If you are not getting enough juice down at the starter itself the solenoid will pull in and not make good enough contact to turn over the engine , but if you are sure the starter motor itself is running ,then the bendix drive is suspect. I don't remember if the bendix drive is engaged by starter spin or mechanical linkage, but in either case it sounds like you are losing voltage down to the starter itself. A thorough check of the cables is in order and the wiring to the solenoid at the starter . I believe there is another solenoid that has to be activated when you turn the key to start and this solenoid then activates the solenoid at the starter . You might want to check that out. Check and follow the wiring and make sure all the connections are good.

 

sounds to be the bendix isnt working,not comeing out .i would sure take a look at that flex plate,might have some teeth gone.hope not,lotta work for a little problem.