fuel problems won't start need help

alright so for the last couple of days I've been having major issues with my jeep. Drove it to a buddy's house in biloxi, ms from my home in memphis, tn. Drove fine on the way down no issues of any kind. Next day We decided to go ride around and it wouldn't crank. I couldn't hear the fuel pump running and the gas gauge read zero even though it was full so I assumed it had a bad fuel pump. Took the tank down and test tested the fuel pump with a 12v source and it ran fine. At least it seemed to. Then i tested the wires running to the back and I was getting one wire with 12v's, 2 ground wires and one wire that seemed to be dead. So I cracked open the fuse box under the hood and checked the relay. It wasn't working. no ground going to the relay. So I spliced a ground wire into the rely and now the pump runs, but the jeep still won't crank. Seems like it may not be getting enough pressure up to the fuel rail, I took the tester nipple off and pressed in the valve and it just kinda leaked out instead of spraying. I'm stuck here. Don't know what to check what to change out or where to begin now. Could it be the auto shut down relay causing problems? Maybe a bad pcu? Some other ground not connected?


Also for the last few months the jeep has always been slow to start. Ran fine once cranked. But i would have to cycle the key a couple times to build fuel pressure for it to crank. I searched on here and heard it was a common problem and that It could be fixed with a 1 way valve in the gas line I just had not gotten around to it.

Sorry so long, I just really need some help here guys.

so here's what I have right now
gas gauge not working
fuel pump wasn't working due to no ground at relay. (couldn't find where ground was broken so I spliced in a new one)
with a ground spliced into the fuse box the fuel pump runs, but not pushing enough pressure for the jeep to start (i'm assuming this is the reason, seems to be very low pressure) Gauge still dosen't work even with splice in fuse

All help is great, even if your not sure just post up ideas for me to check. Kinda stuck here until I get this fixed so I'm open to trying anything.
Thanks as always

forgot to mention its a 2000 model 4x4 4.0 xj

Ok, not sure if I am understanding your post.

You say it won't crank. If it won't crank, why are you messing with the fuel pump?

There is not cranking, and then there is cranking won't start.

What is your situation?

sorry for the confusion. The motor spins over freely. I sprayed some ether into intake and it fired for a second, but it will not start and run. I've been doing some reading and it sounds like I may have a bad cps. but i would still like ideas.

like I said it turns overjust won't fire and run. So I guess you could say it trys to crank, or it will crank over. Just not actually fire up due to what i think is a lack of fuel
thank you

Well, I had a similar problem. Once I repaired the fuel pump it took a while for pressure to build up. Pull the fuel pump relay and short out pins 30 and 87. The fuel pump should kick and stay on. Press the schrader valvle to purge air from the fuel lines. Once pressure builds up, replace the relay and start the vehicle.

Give mflueras idea a try. If it doesn't work, then try swapping your relays around as it might be a bad ASD relay.

If it is just a fuel problem you should be able to spray ether into the intake and it should run, at least until you stop spraying.

just an update. I replaced the cps today and now the jeeps cranks but and starts to run but shortly after dies. Seems like it is not getting enough fuel now. If I short out the fuel pump and let it run for about 10 seconds the jeep fires right up but then it seems to die due to not getting enough gas fast enough. Maybe the pump isn't pushing enough gas? or is there a pressure regulator I should check?

Rent a fuel pressure gauge and see what you have got, it should be 49 psi.

Your late model has the pressure regulator and filter in the tank, and you have to drop the tank to change the pump assembly. You need to confirm that the pump assembly is the problem before going to a lot of trouble and expense.

After jumping the relay as described in my previous post, start the jeep then try to keep her running by spraying starting fluid into the air intake when it is starting to starve for fuel. Do this for up to a minute or two. Sometimes it takes quite a bit for the pressure to build and everthing to come into play.