2002 dodge ram 1500 crank but doesn't start

I recently worked on my truck
cleaning all wire connections
on the throttle body spark plugs
and even replacing spark plugs.
I've cleaned and replaced them
before with no problems but
this time around I  
disconnected the wire
connections to the fuel
injectors to clean then while I
have everything out of the way
but when I put everything back
together it sounded like it was
going to turn on but just kept
cranking and didn't turn over. I
don't know if I did something
wrong by disconnecting them
but I've spent hours looking
through the repair manual for
answers but still have yet to
figure it out. With all my luck
going on my battery  started to
lose its charge the first time
trying to stArt it, making it even
harder to find possible answers
while I wait for it to charge with
my battery charger. Keep in
mind I also tried while hooked
up with cables to try and jump
it but still no luck. I know I need
to replace battery but could
that also be a reason for
cranking but not starting? I was
also on empty on gas at the
time working on my truck and
was only able to put 2 1/2
gallons from a gas container I
had set aside in my garage, so
it's not completely empty but I
have to walk half a mile in order
to get more gas and I'm hoping
I could solve this problem
without walking, but could that
also be the problem to my
solution? I appreciate any
feedback