what would cause this? won't start/backfire
 

My FC has been sitting for about 2 - 3 weeks now due to water pump issues. It has not been started or driven since then. Today I put it all back together and tried to get it to start, but when I tried the car would not turn over. I then asked my dad to come out and crank it while I watched the engine... Nothing really caught my attention aside from the fact that my car was not starting.
I suspect it is either flooded or just out of gas. I know I was really low, but I didn't think I was empty.

Side note: While my dad was trying to start the car, he was pushing in the gas. I don't think this really did anything because before he was doing that I tried starting it and I had no luck...

Anyways... I hope to hear from someone soon.
thanks for all the help everyone, I really appreciate it.

From what I gather, the engine will indeed turn over, but will not start?

If it's not even turning over then you should check the battery connections and the starter. Perhaps the battery has died or the starter is stuck.

If it turns over but does not start, then start with your first assumption and put some fuel in the tank.

Note that S5s have fuel cut during cranking so if your dad was pushing the pedal, fuel was being cut from the engine.

yeah i guess i worded that incorrectly...
the batter was indeed dead, but we were jumping it so that shouldn't matter. I'll be putting some gas in later and hopefully that will help.
thanks

so it seems that it just needed some gas. she started right up and seemed to be running better than before.
but i have a question...
we didn't go for a drive or anything, but we did let it idle in the driveway for roughly ten minutes. the temp. gauge was reading just below half way up in a pretty short period of time. the engine was still pretty hot to the touch after the car was off for 45 minutes. is that normal?

Halfway on the gauge is standard operating temp for an S5.