the other day was trying to turn on my 280z and now the starter stay on like is getting straiht power even if i disconnect the switch... can someone please help me

 

Your message doesn't make much sense. I'll describe what should happen, and then you can tell us what isn't happening.
1. The starter is wired to the positive and negative to battery.
2. The solenoid is wired to the ignition key and the chassis ground.
3. When you turn the ignition switch to start, the solenoid receives power.
4. The solenoid engages the starter.
5. The starter meshes with the flywheel and turns the engine.
6. When the engine fires, you release the ignition key.
7. The ignition switch goes to the run position.
8. The solenoid is de-energized.
9. The starter disengages from the flywheel and is de-energized.

So from that description, what isn't happening?

If you need more specifics, consult the EE section of the FSM.