92 xj fuel rail reading 5psi?

[xj1028]

Ive been having a problem with the jeep lately which as been driving me up the wall. With in the past couple of weeks my xj has been running rough with sputtering and loss of power. I replaced the IACV reset the computer and it ran good for about a week. Now with in the past couple of days the symptoms are back which is a slight higher idle than normal and stumbling after reving with a slow drop down to idle. I replaced the TPS and the issue went away only to come back 10 mins later now the truck has trouble starting unless i pump the gas pedal. I replaced the fuel filter and did a fuel pressure test with the key in the on ignition (not running) where it only read 5 psi. I'm leaning toward a bad fuel pump, but i'm also wondering if the fuel regulator is shot. when I cycle the engine i can hear the hum followed by a click from the fuel pump, but other than the weird idling and starting issue when i get the truck going down the road it shifts fine and no loss of power unless im taking off from a stop. Any info would be greatly appreciated.

 

[souske]

Pull the vacuum off the regulator and try again
can you pinch off the return line?

 

[xj1028]

Ill have to go back to work to use my pressure gage so ill let you know on that, but i just turned it over at home and it started/idfled fine. I also forgot to mention that my tank was out of gas yesterday after my fuel gauge was giving me an unaccurate reading oops. Pulled the cap off and hit the tank with a screw driver and alas nothing but a hollow sound. I put 4 gallons in it and it started up fine and ran good till i got close to work. I replaced the fuel filter after that so im hoping something didn't get clogged. Could I have possibly vapor locked it?

 

[Hypoid]

It could be leaking through the regulator.

 

[8Mud]

The fuel rail leaking pressure when the motor is off is pretty standard stuff and never really affected how my XJ's ran. It just made starts a little slow. You really need to check the fuel pressure with the motor running.

Kind of sounds like your CPS may be going out on you. Except for the slightly higher than normal idle.

Check your intake/exhaust manifold bolts.

Can you do a key test and the check engine light to check for any stored codes in the computer on a 92?

I had a leaky valve cover and my CPS was covered in oil and crude. Just cleaning it off made a heck of a difference. My guess is bits of metal, rust or whatever get stuck to the oil and mess with the CPS.

 

[xj1028]

I have a snap on chrysler-1 mt2500 adapter and i ran the codes. There was no codes of any kind stored which amazed me. I should also note that i have the notorious cracked exhaust manifold and it pisses air out on acceleration. Im almost curious to see if the heat coming off it could have damaged the crank sensor harness since it runs right by there. The truck appears to be running fine now. The past couple of times I have started it tonight the problems are gone. Even went to get fuel and put some injector cleaner in it so we will see what happens I still don't fully trust it yet.

 

[souske]

Get a new exhaust manifold, they are only $100 from 1a auto

 

[GrimmJeeper]

I had a similar issue and it ended up being the rubber hose that goes from the pump itself to the metal nipple that passes through the mounting plate for the fuel level sensor in the tank. it had rotted out and would leak internally inside the tank as the pressure in the line went up. 3" of fuel hose and I was back in business.