i just rebuilt my engine its a s4 n/a and i have the timing close to as i can without the engine being on to time it but i try to start the car and all it does it rotate and once in awhile i get a very loud bang (backfire im guessing) the engine has fuel spark and compression ii have no clue what it can be PLEASE HELP

 

its still off re-stab it

 

new seals? I was having the same problem...loud pops when cranking. It was flooded, bit time! I believe the problem is cold start fuel enrichment combined with low compression. I have managed to get mine running 2 times once its up to normal temp. I can shut it off and restart no problem. Cold though, it just floods...the bitch!
I've had some success with the ATF but once the plugs get wet its over for the day.
Make sure you have a FULLY charged battery, or a jumper box, cables or something cause this will kill your battery in a few tries.

 

yeah i have all new seals in it and like you said once the plugs get wet from the engine flooding its done for awhile.... but how long should a fresh rebuild take to start for the first time ?