I have a mini high torque starter that got messed up. After trying to crank my engine for the first time, my starter stopped kicking out after a nasty backfire. However. when I took the starter off the car and turned the key the starter would kick out and turn. But when its back on the car it doesn't kick out and just spins the gear insinde the housing. Do I need a new starter or is it fixable?

do you have the correct starter for the flywheel?

My guess is a bad engine ground. Re-check all grounds: firewall to engine, engine to frame, engine to battery, etc.

No I'm not a retard its the right starter and its all wired good hence the starting that it was doing before it busted. But the problem just got weirder. After looking at it more when the starters in the car it is already kicked out before I do anything and when I crank it doesn't spin the gear but makes a spinning noise instead.

from your first statement, it sound like you broke something inside the starter. the starter motor is turning but the solenoid isnt kicking out the drive. Do you know why the motor kicked back in the first palce? Is your timing correct?

yes my timing was wrong thats why I was cranking it so long trying to get it adjusted. I took the starter out and bench tested it and everything worked fine. But in the car it's all fudged. The starter kicks the gear out and keeps it there before I turn the key and when I do turn the keep it makes a whining noise and doesn't turn the gear. Anybody actually know something about starters that knows whats up

Sounds like it rocked back when it backfired and broke the bendix...
My advice, in light of the question, is get yourself a rebuilt starter... or be brave and try to replace the bendix. Not a big deal, but will require complete disassembly of the starter.

Look at the two scenarios- 1. On the car the starter doesn't work. It does has power to the starter, correct? The starter does nothing, as in bendix does not come out and engage the flywheel and the motor does not sound like its on, right? 2. Off the car, the starter does work. It does have power to the starter, correct? I am assuming you used a battery charger or something similar and attached the ground to the body of the starter, right? This completes the circuit. So, like Cardinal said, if these things are true, the first thing I would check is whether you have a good ground when the starter motor is on the car. The ground there is the engine block. So the block needs to be grounded. Make sure you have a good connection whereever the ground strap is attached. Make sure there is no corrosion as well. Usually the first thing to check on a DC circuit problem is the ground.

ok so i opened up the starter and it turns out the nylon ring gear for the planetaries had all the teeth stripped off.