The fuel pump ultimately died, and I had to replace it. Here are some of the troubleshooting 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 it 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 the 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 frequently it would happen until after about six tries beginning; it just wouldn't do anything. So this led me to believe that there was some fuel in the line initially, but as I tried to start it, the fuel eventually ran out.
I checked to ensure the fuel pump was priming when you first turned the key (but don't try to start it). But this is where I got tricked. There is something in the engine bay that primes when you first turn the key on. You need to get down near the fuel pump to verify.
To get to the fuel pump, yank the rear seat up. It has clips that hold it to the base. Push all the seat belt latches through the holes. You must 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 you have to fight the auto lock.
I also took this opportunity to wash the rear seat base since they had some kid stains and were free from the car. I used a water hose, laundry detergent and a plastic bristle brush. The seats dried after about two days, and the stains were gone.
You should now see the fuel pump cover. Twist the three plastic locks, and the body 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 it's pushing fuel out. Push the tabs on the little white plastic seal to get the fuel line off, and pull the black hose part back. I hooked a piece of hose to the fuel pump's outlet 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 that you won't unload your fuel tank into the water bottle. Be sure to put some rags under there if the line is pressurized (it should be in typical situations). And make sure you are in a well-ventilated area (garage door open).
If you have a little pressure, 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, you have 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 on the driver's side, fender well by the battery. It has four clips. You pull the "lid" off and turn it over to see all the fuses and relays. For some lovely reason, the owner's 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 labelled on the underside of the IPDM cover. The relays are not marked, but it doesn't matter. There is a fuel pump relay in the IPDM, but it is internal and not user serviceable.
Since the fuel pump and IPDM are expensive, we don't want to guess. So first, troubleshoot the IPDM. Verify the fuse for the fuel pump is ok. Depending on which design you have located pins 1 and 36, these are the two we will care about. Pin 36 is brown-coloured and indicated by the IPMD schematic. Use a multimeter with sharp points on the leads and stick the black tip against some bare metal on the car (I used the battery tray). Then attach the red lead inside the wire harness. You want to cram the needle part of the lead next to the wire so that the information is touching the metal pin inside the saddle. Stick the multimeter on the cowl (in front of the windshield). Set it to DC mode and turn the key, but don't try to start it. Pin 1 should have a constant of 11-12 volts. Next, check pin 36; you should see the multimeter jump to 11-12 volts for a second and then quickly start going down. This is the voltage used to prime the fuel line; it turns the pump on for a second.
If the IPDM passes inspection, then move to the fuel pump harness. 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. I replaced the fuel pump, and the 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 than that. You can stick a cap over the nipple to keep the fumes and loose fuel to a minimum. Oh, and your fuel pump will probably be filthy. This access port opened outside; mine was filthy. This is after some heavy Windex and rags, which I recommend when working around the fuel pump to keep particles from getting in the fuel tank.
The tool to rent from AutoZone is part 27160, called the "Fuel Pump Replacement Kit." It's $90 to rent, which you get fully refunded when you return. 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 turn anything as you will push on the back of the more full charges.
The brand-new fuel pump is in place.
I hope this helps fix your piece of crap, Versa. Three years old with 83K miles and a new engine and fuel pump already.