Engine will not start. Checked the relays, fuses,

You need to see if your fuel pump is running. When you turn the ignition on you should hear the hum of your fuel pump running for a few seconds. If you don’t hear it then check your fuel pump fuse then relay.

If your fuel pump is running check the fuel pressure at your fuel rail on top of the engine, depending on year, make and model.

Any more questions try me at https://www.6ya.com/dennis_c04c6fee69bc17ab

its on the drivers side wheel well. when you pull the cover off there is a sticker in the cover with the layout of all the fuses and relays and each one is marked accordingly.

Have you checked for spark? Also just because the fuel pump kicks on doesn't mean that it has enough pressure. It only operates within a small PSI window. Any check engine lights on?

did you check all fuses with a meter ?
you are new to jeep repairs.... here are some facts.
jeeps have ASD relay.
when car dont start, see what the ASD relay is doing
do not throw parts, you picked the most hard and expensive thing to change on a lark. why do that?
the fuel pressure gauge is $20 and takes 5min to see that fuel pressure is good. not pulling the tank and pump. for fun.
why do that.? (seen 100000 times on forums, this....)
here is mr. ASD, and what to check.
the ASD can cut fuel and spark for many causes. x8

http://www.fixkick.com/Jeeps/ASD.html

automatic shut down relay.

does the relay close cranking? y/n ?
if yes, does it then drop out cranking, y/n?

those are the first 2 tests on all jeeps 1993 to now.

each check discovers what is wrong
so does attaching any OBD2 scan tool and cranking
for 5 long seconds and behold, DTC errors.
got DTC errors cranking/??

BINGO x10.

Hopefully you checked the fuse and relay for the fuel pump before spending the money to replace those items. If you're not hearing the fuel pump kick on, you aren't going to have pressure. P0300 is a misfire code that was probably stored due to the engine failing to start since there was no fuel pressure.
Check that there is 12V at the fuel pump if you can't hear it. You will need to have someone turn on the key because the power to the pump only stays on for a few seconds unless the engine is started immediately. This allows it to prime the fuel line. Once you have confirmed that there is power to the pump, check the fuel pressure at the fuel rail to rule out a pressure regulator problem.

check all your rounds on the body, behind kick panels, and in engine compartment. The relays you hear clicking are the power relay whcih turns your engine computer on. The other relay is the fuel pump relay, which is turned on by the engine computer. start there, report back.

PS. When you press the gas pedal to the floor during cranking, it shuts off the fuel supply to clear a flooded engine.

put a funnel in the gas nozzle have someone turn ignition on to almost start, but don't. You should hear pump running before you start your van if you don't hear the pump you know you have a defective pump if you hear the pump purchase a fuel filter try that if not possibly could the relay not sure where its at but could finds out for you.good luck

you didnt list the year make or model, only fords come with fuel shut down switches and they are located in diffrent areas, behind left kick panel or in the truck on the leftside or rightside and then the right kick panel but only ford has this, good day, if you want to send the year make and model i will be able to help you further.

You need air, fuel, and spark to start your vehicle. It may be the fuel pump, filter, fuel pump fuse/relay. You should be able to hear the fuel pump kick on when you first turn your key. Fuel goes to the pump, filter, lines, and engine. If it is getting gas, you need to check for spark. Spark plugs/coil wires, distributor, dist.cap, cam sensor, ect. It can be anyone of them. Check for gas and spark.

Have you checked if the pump is actually pumping gas by removeing the fuel line from carb stick it in glass jar and have someone else crank engine . if gas pours out change fuel filter if not replace fuel pump. if you are fuel injected disreguard last. get fuel pressure tester from auto parts store .they will hav specs on how many pounds of pressuere you should have if pump checks out good try replaceing fuel filter.