I just replaced my cat converter on my 2010 HHR 2.2L and It cranks acts like its going to catch for a second and won't start just keeps cranking, I have fuel and spark fresh oil change New O2 sensors none of the wiring is damaged but the battery went dead over the winter so have tried a jump pack and my V8 2006 dodge ram 1500 to jump it but still no Joy any ideas about this issue?

 

Where are you connecting the jump pack? The power lug under the red plastic boot in the under hood fuse block and then the ground on the strut tower on the drivers side ? Or are you connecting directly to the battery posts?

 

The correct hookup is on a sticker on the fuse box lid. If that has disappeared instructions are in the Owner Manual (link in my sig).
If you used the lug nearest the firewall on the fuse box for ground you have blown the power steering fuse and possibly done other damage.

 

Have tried both even put the battery on a trickle charge but got it to start this am however its now rough idling and when you turn the key to off its acting like a car from the 60s/70s with the engine knocking and pinging before dying Did a code scan its showing the O2 Sensor Bank 1 not working , The MAF Sensor not reading, Cylinder misfires I'm thinking that is just from Intake exhaust sensors may need replacement again its been a few years ABS codes along with a bad wheel speed sensor If any of this is connected please I welcome the help

 

Battery sitting in the cold in a discharged state is permanently damaged. Get a new one. Might not be the only problem, but trying to fix this with a bad battery is futile.

 

I suggest you tighten those four bolts in the under hood fuse box, real tight! And replace the battery, most likely a dead cell .