When your car won't start, but will crank, the engine isn't getting fuel or a spark. You can troubleshoot the fuel system in your Nissan Sentra before you take it in to a mechanic. It is always helpful to use a service manual specific to your Nissan Sentra to help you locate all parts in the fuel system.
Check the weather channel or your local weather readings, first, to see if there is a possibility that you have Vapor Lock or ice in your fuel tank. When the temperature is below 30 degrees, adding de-icing in the gas tank may help. In heat above 80 degrees, pour cool water on the fuel pump and the fuel lines.
Park your car on a level surface, add some gas to the tank, and try starting the vehicle again. When your car is at an angle, the fuel injector may be pulling in air instead of gas.
Test the spark plugs with a spark plug tester. These testers can be purchased at most car part stores. Once you connect a spark plug to the tester and turn the car on, you should see a spark in the gap. If no spark appears, you should replace every spark plug.
Take off the fuel line with a fuel line disconnect tool, place it in a clear container, and start the engine. You should see fuel coming out of the line when the engine is engaged. If you do not see any fuel, you need to have the fuel pump tested and possibly replaced. If you are unable to reach the fuel line, as it is located under the passenger's side of the vehicle on a Nissa Sentra, you may have to take it to a mechanic who can lift the vehicle into the air.
Examine your rubber fuel hoses. Remove them, squeeze them for soft or brittle spots, and replace the hoses if any of them have these problems.
