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Bad fuel pump or clogged filter?

93XJ2drSport

NAXJA Forum User
Hey guys, just had a problem with my 93 4.0 HO 5spd XJ today, did a search on here and am probably more confused now than before.....This is what happened.....Jeep has been fine, no problems for years, had a valve cover leaking some so replaced gasket, changed oil/filter....Took it to town today, drove it around for over a hour, just got back and stopped at McDonalds.....While sitting in line, noticed that it started idling rough, almost died when I gave it gas, THEN I NOTICED THE FUEL PUMP BECAME VERY LOUD, COULD HEAR IT QUITE CLEARLY, NEVER COULD HEAR IT BEFORE...SOUNDED LIKE IT WAS NOT GETTING FUEL....got food and was barely able to get it out of the drive thru to the parking lot where it died, acted like it had just ran out of gas....It tried to start, but it just sputtered and died and would not run....Gas gauge said 1/2 tank of gas.....Was within walking distance to house so I walked home and got a gas can full of gas thinking that maybe my gas gauge might be faulty, put it in and jeep fired right up, drove home fine....Had it in garage idling for awhile and it started acting up again, acting like it is running out of gas until it dies, but will start up again, be OK for a few minutes then acts up again.....Fuel pump is running (I was laying under tank while this was happening) but it sounds like it is skipping or missing not just running consistently...It has never been changed (I've owned this jeep for 12 years) did replace fuel filter a few years ago....Does this sound like fuel pump going bad?....Figured I would change filter to start and check the ground strap to motor since I was just monkeying around there doing valve cover gasket....Just thought I would check in here with symptoms to see if any of this sounds familiar, thanks
 
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1. Check fuel pressure with a gauge.

2. Check volume delivery.

3. Post up your findings.
 
Totally agree with Joe. You must get some fuel delivery data to see what is going on. The fact that you have symptoms along with a loud fuel pump makes the pump suspect.

Many parts stores will rent you a fuel pressure gauge inexpensively; call around. Select the right fitting and screw it onto the schrader valve on the fuel rail.

For a 93, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to approximately 39 psi. Be sure that the vacuum line to the regulator is pulling good vacuum and is not wet with raw fuel.
 
Or a loose hose or loose fuel pump inside the tank. A lot of reports of the ethanol fuel blends eating the output hose on the pumps. The hose was bad, inside the tank.
 
Just a update on what I found with this; Determined that pump was not putting out good fuel flow, so removed it and found that a seal that went around base of pump to seal the pick-up had been sucked into bottom of fuel pump, looked like a black twisted up rubberband..... Replaced the pump with new Bosch unit and rig runs like brand new.
 
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