Starter keeps turning over with key out of switch

The fuel relay will activate for 3-5 seconds every time you turn the key on. It should not keep the engine from cranking. I have seen problems with the ignition switch that will keep the truck from cranking. Make sure that the battery connections and clean and tight. Check to see if 12 volts are getting to the starter when you try to crank it. Hold the key in the start position and while holding it, strike the starter with a hammer. If it starts , replace the starter.

Did you replace the key switch ?

• Check Your Fuses: Few cars have a fuse associated with the starting system, but before you go monkeying around with everything, check your fuses to be sure it's not that simple.
• Battery Corrosion: Over time your battery connections can become dirty, or corroded. This corrosion breaks the connection your battery has with the rest of the car, and it won't start. Try cleaning your battery posts and try to start the car again.
• Dead Battery: The most common reason your car won't start is a dead battery. If you have a battery tester that can measure cranking amps, test your battery to see if it's weak. If you can't test it yourself, you can test the battery indirectly by jump-starting the car. If it starts right away, your problem is most likely a dead battery. Replace the battery, and clean the battery connections to ensure good contact.
• Bad Igntion Switch: If your battery checks out, but the starter is still silent, it may be a faulty ignition switch. Turn the key to the on position (not all the way to start). If the red warning lights on your dash don't light up (and your battery connections are clean), the ignition switch is bad. If they do light up, turn the key to the start position. The dash warning lights should turn off at this key position (most cars). If you're not sure, turn on the headlights. When you try to start the car, the lights should either dim (a lot) or turn off completely. If they do, your ignition switch should be ok. If not, the switch will need replacement.
• Bad Starter Connection: Corrosion can not only keep your battery from connecting, it can affect any electrical component, especially the ones exposed to the elements like the starter. If you have a helper, you can test the connection by holding a circuit tester lead on the wire that engages the starter. This is the smaller of the two wires connected to the starter. Be sure no part of your body is near the moving parts of the engine - it could still start at any time! Have a friend turn the key and check the current. If you're getting current to the starter but it ain't spinning, it needs replacement.

If your starter spins freely when you turn the key, the problem lies elsewhere. Now you begin to check the other systems that could keep it from firing up.

there are a few things that will cause this problem 1 is a stuck solenoid, 2 starter drive pinion stuck in the ring gear or flywheel. 3 ignition switch is shorted internally. I would try tapping the starter motor with a hammer or steel bar then turning the key to the on position... If the problem is gone replace the solenoid.

Check starter solinoid

My first guess would have been the clutch switch but that would not prevent the engine from starting.
Something is not making the circuit from the key to the starter solenoid and the coil or computer.
Assuming the key is turning the switch correctly, you would need to troubleshoot the circuits with a meter coming out of the key switch. Its possible the key lock is not actually turning the switch.

starter switch maybe loose

check your wires under the car at the starter. make sure that the wires arent damaged and stuck together. if they are fine replace your ignition switch. should come in 2 parts. replace the electrical portion. keep your key.

the neutral switch is to prevent the starter from engaging if not in park or neutral - try just bumping the key switch without holding it - the key lock or ignition switch could be keeping power on starter or the starter solenoid could be keeping the starter engaged someone would have to be under the car listening or touching the starter to see this or measuring voltage on solenoid wire

NEED TO REPLACE STARTER.