The fuel pump completly died and I had to replace it. Heres some of the trouble shooting I went through.
For reference, here are the costs of some of the parts:
Fuel Pump Assembly $340
Packing-Fuel Guage (big O-ring for the fuel pump assembly) $37 (not required, your choice if you need or not)
Fuel Pressure Regulator $28 (included on new fuel pump assembly)
IPDM (the relay and fuse box) $300
The fuel pump, pressure regulator and IPDM are all known to be issues, the pump and regulator more so. See this thread for info on pressure regulator service bulletin
What happened to us was that the car died. Upon trying to restart, it would get a cylinder fire here and there, but the more we tried to start the less frequent it would happen until after about 6 tries starting it just wouldn't do anything. So this led me to believe that there was some fuel in the line at first, but as I tried to start it the fuel eventually ran out.
I checked to make sure the fuel pump was priming when you first turn the key (but don't try to start it). But this is where I got tricked. There is something in the engine bay that also
primes when you first turn the key on. You need to actually get down near the fuel pump to verify.
To get to the fuel pump, just yank the rear seat up. It has clips that hold it to the base. Push all the seat belt latches through the holes. You will need to unbolt the middle lap belt and feed it through the hole.
Once you have the middle belt free, a trick I do with seat belts is to put a zip tie around them near the retractor. This way the belt doesn't fully retract and then you have to fight the auto lock.
I also took this oppurtunity to wash the rear seat base since they had some kid stains on them and was free from the car. I just used a water hose, laundry detergant and a plastic bristle brush. The seats dried after about 2 days and stains were gone.
You should now see the fuel pump cover. Simply twist the 3 plastic locks and the cover will be free.
You now have access to the fuel pump.
Now you can listen to see if it primes. You can also test that its actually pushing fuel out. To get the fuel line off, push the tabs on the little white plastic seal and pull the black hose part back. I hooked a piece of hose to the outlet of the fuel pump and then stuck the line into a water bottle. Turn the key on and see if any fuel comes out. The fuel pump only pumps for a second so you won't unload your fuel tank into the water bottle. Be sure to put some rags under there incase the line is pressurized (it should in normal situation). And make sure your in a well ventilated area (garage door open).
If you have a little bit of pressure, then you might have a bad pressure regulator. It is on the fuel pump and the fuel pump will need to be removed. See further down on how to do that.
If the fuel pump doesn't prime then you have either an issue with the IPDM, the wire harness or the fuel pump.
The IPDM (Intelligent Power Distribution Module) is located in the engine bay. It is a flat black thing in the driver side fender well by the battery. It has 4 clips. You pull the "lid" off and turn it over to see all the fuses and relays. For some lovely reason the owners manual makes no mention of this module, yet it has the fuses in it that are most likely to leave you stranded. Verify which version/shape IPDM you have.
There is a fuse that can be inspected. The fuses are labeled on the under side of the IPDM cover. The relays are not labeled, but it doesn't matter. There is a fuel pump relay in the IPDM, but it is internal and not user servicable.
Since the fuel pump and IPDM are both expensive we don't want to guess. So first trouble shoot the IPDM. Verify the fuse for the fuel pump is ok. Depending on which design you have locate pins 1 and 36, these are the 2 we will care about. Pin 36 is brown colored and indicated by the IPMD schematic. Use a multimeter with sharp points on the leads and stick the black lead against some bare metal on the car (I used the battery tray). Then stick the red lead inside the wire harness. You want to cram the needle part of the lead next to the wire so that way the lead is touching the metal pin up inside the harness. Stick the multimeter up on the cowl (in front of the windshield). Set it DC mode and turn the key, but don't try to start it. Pin 1 should have a constant 11-12 volts. Next check pin 36, you should see the multimeter jump to 11-12 volts for just a second and then quickly start going down. This is the voltage used to prime the fuel line, it just turns the pump on for a second.
If the IPDM passed inspection then next move to the harness at the fuel pump. The same brown wire is what has the voltage. Stick your multimeter red lead into the harness pin, and the black against some metal point around the fuel pump cover (or use the thread from where you took out the seat belt). This is where my test ended. Had the short 12V burst at the harness. So the fuel pump was now the end of the line. Replaced fuel pump and car started right up.
To get the fuel pump out you need to rent a tool from Autozone. Don't try to use a hammer and screwdriver or chisel. You will need WAY
more leverage then that. You can stick a cap over nipple just to keep the fumes and loose fuel to a minimum. Oh and your fuel pump will probably be filthy. This access port opens to outside, mine was filthy. This is after some heavy windex and rags. Which I would recommend when working around the fuel pump just to keep particles from getting in the fuel tank.
The tool to rent from autozone is part number 27160, called "Fuel Pump Replacement Kit". Its $90 to rent it, which you get fully refunded when you return it. Use the tool circled in yellow. Adjust the metal legs to push against a tab on each side. The square hole in the top bar is for a 3/8" socket wrench. We used a 2 foot long 1/2" breaker bar with a 3/8" adaptor and it took some incredible force to get the lock ring off. We ended up bending most of the tabs, and then just straightened them out afterwards. Going back on you won't bend anything as you will be pushing on the back of the tabs which are stronger.
Brand new fuel pump in place.
Hope this is helpfull is fixing your piece of crap Versa. 3 years old with 83K miles and new engine and fuel pump already.