ONE CHANNEL OPERATION
KX series amplifiers are capable of operating into a minimum impedance of
2 ohm for the KX400.1, KX600.1 and 1 ohm for the KX1200.1.

Problems
3.) Amp will only play at low volume levels.
"Short circuit protection is engaged. Check for speaker wires shorted
to each other or the vehicle chassis. Damaged speakers or operating
below minimum impedance will also cause this.

RMS Power
In Watts
@ 13.8V, 2Ω Mono, 1.5% THD 600 X 1 RMS
Dynamic Power
In Watts
@ 14.4V, 2Ω Mono 690 x 1

Check your ground, it might suck.

Sounds like a bad ground.

And although I don't recommend it as it will shorten the lifespan of the amp those 500a2's will run 2ohm mono all day long unless you're running tones flat out.

ground
 

4 guage ground wire and I sanded off all the paint and bolted it down with my rear seatbelt shouldn't that be good?

With you're rear seatbelt? Screw if to bare frame.

car is a 2005 honda civic where should i screw this ground wire to ?

The windsheild

Yea try windshield or battery positive.

was that neccessary? I mean is the shock tower bolt a good spot or ?

i mean i unbolted the rear seatbelt and sanded it all off to bare metal , the car body i mean not the seatbelt , than put my ground to it and bolted it down