I have a 2006 Sentra 1.8, 5spd that is kicking my butt. You can crank it all day long and it won't start. For the last 8 months that I have owned it, it has had long start issues, but it always started.

Car ran fine, parked it in the evening. Wife went to start it the following morning and it wouldn't start. No codes.

Thing's I've done. New cam and crank sensors. Car has spark on all 4 cyl. Car has injector pulse according to noid light. Car smells like gas when you try to start it. Fuel pump does come on. I removed the fuel line and put a gauge on it, and while cranking it makes about 52 PSI. The moment you stop cranking the pressure goes to zero (bad FPR?). As far as I can tell the motor is in time. I pulled the valve cover and upper timing cover and when the crank pulley is set to TDC, the cams are in the same position as indicated in the FSM.

I have not checked the pressure inline with the injectors hooked up and while cranking as I didn't want to cut my fuel hose to put my T-adapter into it.. But I would assume that if a gauge on the end of the line is indicating 52 PSI, it would be ok?

Any ideas?

One other note, if I push the pedal the the floor while I am cranking, it will spudder a few times, but not enough to get it to start.

I can make one suggestion that is totally thinking outside of the box. I have a 1996 Sentra that was giving me problems starting and by accident I found the mass air flow sensor was bad. I found this out by accident. I was checking all kinds of things and for some reason I cranked the engine with the connector unplugged and it fired right up. When it was running I plugged it back in and the car died. If the connector was backed out just slightly and looked like it was connected the car would run. I posted this recently on here when I was having problems. It did smell like gas when I was cranking too but would not start. No guarantee this is what is going on with your car since yours is newer but worth a shot.