My amp is on but when the bass hits it pulls the sub back and it goes into protect mod what can i do to fix this?

If you can tell that it is about to hit and the amp goes into protect mode, the amp is being over driven on the input.

Bad or shorted voice coil on sub maybe. If you have two subs try them one at a time to see if it goes into protect mode. Whatever sub does it is bad.

This could be caused due to the impedance load being to low. Your amp is stable to 2 ohm load however its very possible that you have your subs wired to a 1 ohm load that would cause the amp to go into protect mode. The subs you have are dual 4 ohm voice coils and would need to be wired in series/parallel. I've included a link that will show you how the subs should be wired.

http://a248.e.akamai.net/pix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/2-DVC-4-ohm-mono-low-imp.jpg

Sounds like your amp isnt powerful enough to power your subs, whats the wattage of your amp and both subs? Its shutting off when hard bass hits to protect itself from blowing, a good feature as a blown amp means a new one. an amp should always be more powerful than the speakers / subs you are connecting to it. for 2 500w subs your looking at a 1200w amp minimum.

sounds like ur gains are set to high and is going into protect mode

also what ive seen happen before is the speakers (if mounted in metal shelf or door and arnt bolted down correctly can flex under bass notes and flex the speaker that much the termanls short onto the metal and amp hits protect mode
(rare but worth a look if you think u have elimanted most other things Had a dude come to me when i was working in sydney with this problem )

also could be things like clipping protection , overheat protection ,amp drawing to much current from the alternator

do your lights dim when you hit the bass notes ?

get back to me and im sure we could solve this problem

You need more current.Bass notes require more juice and the best way to get more power for bass is to add a power capacitor to your system . They are easy to install and you can get one for less than a hundred dollars that should be enough for your amp and subs.

1st of all secure your subs/amps good. the tighter they are not only is it safer but your bass will hit harder cuz the box can't move and absorb any of the sound... As far as your amp, check the fuses on the amp. when your ground was disconnected it could have easily fried a protection fuse in the amp. To fix this simply replace the fuse with a new one of the same ampere rating, it shouldn't be hard to find. If all your fuses are good you'll have to see a service professional to fix your amp, or get a new one.

are you factoring the ohm rating from running them parallel?

2 x 2o subs parallel = 0.5 ohm (lowers ohm's)

2x 2oh subs series = 4 ohm

IT is posable that you are calculating the ohm rating fine, BUT some SUBS can reach lower ohm rating while hitting bass- i didnt know this till i had a rather insane sub that would dip to 1ohm while hitting hard bass causing my amp to go into protect mode.

probably your power is too short, increase your gauge wire, and your ground wire of the amplifier has to be shortly as possible, and the positive has to be enough to support peak power, you can also put a big capacitor on the positive wire to give some more power while the bass peak.

your amp try to protect itself from damage when he feels some trouble from your sub.-start by changing sub cabel and sub itself if it does not becomes ok.
if all above failed---you have serious problem in sub output stage and can be fixed in service center.