Well either the physical actuator at the starter is sticking or something is sending it power. You need to trace the electricity and test the integrity of each switch. You have the mechanical key, the mechanical switch, the electrical relay, the mechanical connection in the relay, and the wiring in between. Its just going to be a process of testing for something sticking and looking for shorts.

 

I didn't know their was an actuator on the starter. How do I go about testing it? And the relay your talking about is the one on the fender by the battery, right?

 

Right, with wires disconnected, check the relay for resistance across the coil side. Then apply voltage to the switch side and measure resistance across the high power side. Make sure the high power side releases. Reconnect the high power leads then turn the key and measure voltage from the wire going to the switch side. It should read battery voltage then zero when the key is released. See if that sticks. The actuator is the part on the starter that throws out the starting gear. You can hear it click back and forth but if it sticks the starter will remain engaged to the flywheel. The beast way to test is is to do it on a bench. Alternately you can disconnect the power wire running from the actuator to the starter motor so it won't spin, apply power and make sure it clicks smoothly back and forth. Personally I would just pull the starter and have it bench tested so you know all everything is good, actuator, actuator relay and motor current draw. I know its harder than it sounds but it can save later headaches and unnecessary parts. The other advantage of all this disconnecting and reconnecting is you can clean and tighten all the related wires and make sure they are in good shape and not shorted. Test each wire when you pull it and make sure it hot when it should be or grounded when it should be with no short or extra voltage anywhere. Testing and inspecting everything in the circuit doesn't take that long and will guarantee everything works as it should.

 

Thanks for the help Warlockk. I have done a lot of research on this and turns out there are tons of threads where people had my same problem. Seems like every thread the OP had replaced everything as I did and still had the issue. Most said they fixed it by installing a new fender mounted relay, but I will test mine. I have heard a good test would be that while its turning over pull the small wire on top of the relay and if it stops it is the ignition switch and if it doesn't then it is a bad relay, bad starter actuator, low amperage battery, or bad/weak grounds. I've heard that the relays can go bad if the connections inside become welded together, but I don't think mine is because it doesn't stick every time I start the truck. I'm gonna try starting the truck by jumping the relay with a screw driver to see if it sticks and if it still does its a "big wire" problem and if it doesn't its a "small wire/ignition switch problem". I saw in one thread where a guy said it could be an out of adjustment ignition switch so I will try adjusting it. He said one way was to loosen the switch nuts and turn the key to start position and push up on the switch to bottom out the spring in the switch and tighten it down, and of course check for smooth operation. Also I heard that today's new fender mounted relays are all junk, so I will be getting a motorcraft one.

 

I really recommend using a multi meter. Its not good form to test things by making them malfunction especially with electricity. Every time it does it it causes more damage. Basically you would do the same thing but instead of pulling the wire off you are just measuring to see if there is voltage. The meter is taking the place if the load ( the starter ) and keeping anything form being damaged while isolating one part from the system. You can also use a test lite but you can't measure how much voltage, test continuity or resistance with a lite. Harbor freight sells meters for $5 or you can get them free with a coupon. Its a tool you will use all the time. I have a good one in my work box and cheepies in every car and lying around the garage.

 

The contacts on the relay are open when relaxed. When energized the contacts close. If you measure DC volts across the 2 large contacts in the relaxed position you would see 12 vdc, essentially battery volts. However, if you measure DC volts across the contacts while energized, a good relay will show 0 volts. A bad relay or one not making good contact internally will show what's called voltage drop, it will be an amount between 0-12. Voltage drop occurs as a result of some resistance across the contacts, some of the voltage is exerted as a result of trying to get across a contact with resistance.

Measuring " voltage drop" is an aviation industry standard when testing large relays. It will immediately indicate the condition of the contacts within. I have found this test to be quite useful for checking the condition of a starter relay on a ford as well.

 

Voltage drop is a good test but not the most conclusive test in this case. Remember the op is looking for a sticking starter , one that keeps running when the key is released. Although still more information about parts condition is never a bad thing. If you get a voltage drop you may as well replace the relay.

 

No doubt.

 

I'll definitely look into getting a multi meter. I'm glad you told me that because I have been wanting to get one since I have been having this issue.

 

Another thing too.. when you say high power side and switch side and coil side I am assuming you mean the switch side being the small wire on top, the high power side being the big posts on the relay, and the coil side also being the big posts on the relay? Sorry for the electrical ignorance