amplifier smoking?

today I was installing a system in my car and when I turned the car on the amplifier started smoking. I'm not too good with wiring/power and all of that so I have a few questions if someone could help me troubleshoot. Firstly, I'm using 8 gauge power wire with an 80 amp in-line fuse. My ground wire is only 12 gauge. Could this cause the fire/smoking in the amp? Second, I accidently bought a 40amp fuse for the amplifier when it says to use a 30 amp fuse. Could this cause fire? Finally, the amp in bad shape and has a bit of rust on the terminals, dust on the top, etc. Could that be the problem? Thanks in advance.

If the amp itself is doing the smoking, the small grouind wire is probably not your problem, however it needs to be corrected.

Overfusing could definitely be causing the amp to smoke.  But if it is smoking, it needs to be repaired.  Simply putting the correct fuse in it now will not repair it.

That really depends on how much rust, and wheter or not the circuit board got wet too.  You will need to remove the cover and see if you see any corrosion on the circuit board.  You may have to remove the amp from the heat sink to determine if the bottom of the board got wet.

If you let all of the magic smoke out of your amp or any other electronic device, it is just about guaranteed that it will quit working.

I feel like the amp may have been damaged to start witth because I put the correct fuse in at first and it blew as soon as I turned the car on. Could that be because of wiring? I'm going to buy a new amp and I basically want to know if my wiring will be okay. Is the 8gauge power wire with 80amp fuse okay or should I get a smaller fuse? I'm going to get 8 gauge for my ground wire as well. Should that be okay or would I be okay with 10 gauge ground wire?