Turn key on and off then check. Pressure might bleed back.

Check for spark if you can. If not buy one these for the drawer and follow the below.
http://www.harborfreight.com/catalog...q=spark+tester

Pull the three front plugs. They might be soaked with fuel from the weak battery not turning the engine over. If so, dry them and put them back in.. you can get an engine started on 3 cylinders..then the other 3 should come to life as the fuel gets blown out of them.