I know there could be numerous reasons for it but I would like to know what I should look into first.

It ran fine this morning but when I tried to start it this afternoon it wouldnt fire up. It turns over no problem but it just wont fire.

Any help would be great

 

Explorers of your year had problems with the camshaft position sensor(s).

I would also look your plugs, wires, fuel filter and pump for starters.

 

Should I look into the plugs and such before the camshaft position sensors?

 

Yes. What motor is this 4.0?

If it's the 4.0, the CPS is very hard to get too.

 

Yes it is the 4.0

 

what does the camshaft position sensor(s) do?

 

The CRANK position sensor breaks the revolution of the crank shaft into 6 (in this case) parts............The CAM position sensor tells the computer when you hit cyl #1

 

It is gettin good spark so I think its a fuel issue

 

Does it sound like it cranks over the same as always, and not faster? If faster, compression is lost and timing belt is likely culprit. (Mine wore out after it shut off and I tried to restart it and it woudn't 'fire', and spun over faster, and I knew that was the cause. Confirmed it by pulling grommet on timing cover access peep hole.) The serpentine-type teeth often break off somewhere on the belt.

How low is the gas gauge reading. There have been cars that for some reason, out of the blue, when they used to go down to empty, now can't, and run out of gas at just under 1/4 tank. This is now going on with my car a few months after new fuel pump and rather than flirt with being stranded I no longer allow it to get to below 1/4 tank. (I disconnected my fuel filter and found no gas came out when cranked!)

You say you have spark, but depending on the easiest thing to test, my gas suggestions, or - check timing to make sure something did not get way out of whack as to when the spark occurs.

Do you have an in-the-tank fuel pump? If so, and you wanted to save initial money by seeing if gas is being forced out the pump to SOME unknown pressure degree, you could disconnect the fuel line before the gas filter and then crank the car a few revolutions with coil disconnected and with hose pointing into container, see if lots comes squirting out. You could have someone crank while you observe as you want to actually witness the force of the gas. (It may come out in healthy spurts like if an artery got severed, if all is well - but this is subjective, but still will tell you something). [ Keep gas from spraying any electrical components, obviously]

 

I finally have some time to look at it. If somebody could tell me about where the fuel pressure test valve is that would be great

 

If it is a fuel issue, starting fluid sprayed in the venturi would confirm it if you have a throttlebody injection. If the car fires up for a couple seconds, then you know it's a fuel problem.