fuel pump

[arnold wente]

i have 2021 defender rode 225 miles last wednesday next day was going to wash it when i tried to start it it woud turn over but not start and sometimes it would backfire so i put new battery in thinking it wasn,t turning over fast enough checked spark plugs they were black but not wet so i put new plugs in it but nothing how can you tell if fuel pump is working i have always used gas from good stations or do i have water in gas any suggestions will help thanks in advance

[Andystoy19]

If you suspect you are short of fuel/no fuel you can spray a bit of starting fluid (or gasoline) into the air cleaner while you are turning over the engine and see if it fires if it does your next step will be to check the fuel pump. You can hear the fuel pump run when you first turn the key on and it may stop when it reaches output pressure. There is a shrader valve on the fuel system (looks like a valve stem) that you can unscrew the cover and carefully depress the center to see if it has pressure if yes the next step is to put a guage on and see if it reaches 51 psi, if not you may need to replace the pump or at least pull it from the tank to make sure its the fuel strainer is not plugged. Before you get too deep you can hold the pedal to the floor for a few seconds while cranking the engine and see if it fires (this should help clear any excess fuel from the cylinders), release the pedal and continue cranking to see if it starts?

The fuse to the fuel pump is F5 (10 amp) and relay R1 in fuse box 1 next to the battery under the passenger seat.

If you need a fuel pump you can try https://www.highflowfuel.com/catalog/fuel-pumps/ for a replacement if you wish.

As far as water in the gasoline if you have been using ethanol gasoline and the sxs has sat for longer perionds the fuel may have absorbed enough moisture from the air to cause phase separation and free water. This is very corrosive so it would need to be drained.

You might try to remove the fuel tank cover and try starting the engine normally just in case the tank vent is plugged and you have a vacuum in the fuel tank, you might hear a hiss when you unscrew the cap. The vent is located on top of the fuel tank next to the connector for the fuel pump and acts as a vent and air intake depending on the fuel temp etc.

This is just my SWAG if you feel its too complex than you may need a trip to the dealer.