bridging a 4chan, 1200w amp

so im relatively new to sound systems in cars, and im trying to learn a little more about it, ive got a pioneer 7950UB headunit, a BN BOSS AUDIO 1200W 12IN SUB and a 1200w max, 4 channel amp(refere to ) This link )and im trying to install it all in my Mitsubishi lancer glxi, i replaced the front 2 speakers and using stock back 2, i purchased a wiring harness for the lancer and used the harness that come with the head unit to wire them together matching wire to wire, i hooked it all up, worked fine for 30mins or so then it would just play for a few secs and go silent, i pulled the speakers out and noticed that the car wiring was back the front then what was on the wiring harness so i thought that all it was is that the speakers where wired up back to front, so i rewired them around the right way, + to + etc, now i turned it back on, sub and amp work fine, the back speakers are 10times louder then the front and all speakers are distorted,i hope i hav'nt burnt the speakers out, but can anyone offer advice on how i can test the speakers? what else might be wrong etc? im just looking for how i can fix this problem. any help is greatly appreciated if you need any more info to supply help, please just ask.btw the front speakers are "PIONEER TS1671 - 6-1/2" 3-Way Speaker 220W Max Power"

After more testing its now come down to i get about 5mins of average quality music before no sound plays without the amp, and with the amp about 60seconds before the head unit turns off and then just powers on and off. can anyone offer advice please? im' about to rip my hair out trying to find what the problem is. Even though this is probably a simple issue to fix for you guys. i have some thoughts about it being that the head unit is over powering the back stock speakers, and under powering the front 2 speakers, but that only explains the back 2 speakers cutting out. i don't know, i'm stumped, please help.

all of the above happens if you have a flat battery in your car. simplest thing causing the most drama, i never thought to look at the power source first, i checked every wire, but now all works well.