Starting Issue-Not A Cranking Issue
 

I have an 02 F250 6.8 with 51,000 miles on it. I recently replaced the battery about a week ago, and only actually drove it yesterday for the first time since replacing the battery. I drove it about 25 miles, parked, and when I went to restart, it wouldnt. The starter doesnt crank, so I mean its not a cranking issue as in cranking, and not starting. It only clicks at the relay when turning the key. It acts like when you try to use a wrong chip coded key. All of the dash lights came on, and I can hear the relay clicking, but thats it. I swapped the relays around, and no luck. If I let it sit a while, about an hour, it will fire right up. The battery cables are tight and free of corrosion. Im tryly stumped here! Im curious, since I just put in a new battery, could this be the culprit? Why will it start fine cold, but not hot? I have NEVER had an issue with this truck until now.

sounds like the starter has a flat spot on it.

Next time see if you can tap on the starter and get it to crank.

Also, do a voltage drop test at the starter .

The starter makes no noise..like a bad starter would. Only the relay clicks under the dash, not solenoid click. This started happening after I put in the new battery.

How do I do that? How can I easily test the starter? This only happens after I drive it and it gets hot. Cold, it fires up with no issues.

You need a digital volt meter . A cheep one is better than none . With that you can check powers and grounds .

Details.....

Check for full power to the starter , check for proper ground also .

I had thought about that, but thought it was odd this happened right after I installed a new battery. The power seems to go no further than the relay. No starter noise at all. Yesterday was the first time I actually drove it since the new battery was installed....and the no start happened after first shut off. Ive never had a starting issue except for the old battery going dead....

What im asking is where do I test it? How? Voltage? Proper ground? Set the meter on what?

Ive never done that before.

Replace the starter, had the same thing happen to me on my 03 f350 v10. You would`t believe the things I tried first , thinking it couldn`t be the starter.

There is no simple answer to your question. Many things could cause your symptoms. To find the problem, testing needs to be done. If you do not know how to test, you need to get someone to assist you. If you knew how to do the test, we could guide you through them, but if you do not know how to test for voltage at the starter, you need to get some "hands on" help.
There is no reason why replacing the battery would cause your problem.

I noticed last night, as I went to start it to see what it would do....After starting it, I ran it for about 10 seconds, shut it off, and it wont restart. Kind of odd that it isnt even hot and wont restart. Seems strange that a starter would cause this.

You changed the position of the armature...you hit the flat spot.

Give the starter the hammer test . If it starts , replace the starter ....