bought 2003 Discovery 2 a month ago - was running great! got home one night & shut off engine; couple hours later unlocked doors w/ keyless fob & engine just cranks over fine but no sign of any ignition; have checked all the fuses; I suspected something possibly wrong w/ security system, but have not found any problems yet; I tried to locate shraeder valve on back of manifold to check fuel pressure but I cannot locate valve, so I don't know if it's getting fuel or not; as a new owner who loves this ride I need help in getting it going again; I am missing the joys of the D2 already!
Please help with advice where to start checking!

 

follow the fuel rails back to the rear of the engine compartment and you will run into the shrader valve

 

after reading all the posts about failure of the crankshaft position sensor I decided that was my problem; bought at Autozone - part made by Bosch - installed today; took me more than 2 hours as some owners state, but after all the PITA difficulty in installing the two bolts & 2 nuts, and in reconnecting the plug, my D2 fired up immediately; Many thanks to all those who have gone before me & provided all the great info & repair advice!