The battery has been replaced. I took in my alternator to have it tested which it came out bad so I replaced it as well.

I put in a new fuse and it blows immediately when the engine is cranked.

I looked everywhere for a short or a wire rubbing in the engine bay no luck.

Any ideas?

 

Possibly a dead short inside your "replacement" alternator. Is the proper alternator in the car, a poor quality rebuild, a junkyard special? Try another alternator to see if the alternator is tha cause of the dead short.

 

so the fuse was popping, you replaced both the battery and the alternator and its still popping?
unplug your o2 sensors and replace the fuse and try it then, if it doesnt pop, its a short in one of the o2 sensors, I have a short in my secondary and it would pop the fuse for the alternator, force my car to run off the battery and eventually ran it down.

 

The funny thing is I had isolated the alternator by removing the plugs and started up the car and still the fuse popped (no I didn't remove the alternator plug while the car was running). I'll have to check the O2 sensor next.