is my fuel pump going out?

CG98XJ · 09-07-2009, 04:15 PM

ok so i am looking to see if there is an easy way to tell if my fuel pump is going out. i can still hear it click on and off. however when i start it and leave it running at idle it will start to stutter and sound like it wants to die and ocassionally will. also after i start it and begin to drive it will sputter really bad around 25-30 mph. then i hear a loud click and it takes off. if the jeep sits for a few days it wont do any of the above. it has been doing this for a while and i have already tried to diagnose it with some other solutions such as new CPS, checked my compression, and i have done a few other things that i cant remember at the current moment. thanks.

XJMuscle98 · 09-07-2009, 04:31 PM

I would say to check the fuel pressure while its idling and just watch it when it acts up and compare the fuel pressure.

**CJ7-Tim** · 09-07-2009, 05:54 PM

The fuel pump is the least likely part on your Jeep to fail.

What is the source of the "loud click" ?

You didn't note the date or mileage of your last routine maintenance tune-up and whether or not your have tested any of the usual suspects like the TPS, or O2 sensors. Have you recently cleaned the Throttle Body and IAC or used some fuel injector cleaner ? Do you have a Check Engine light or have you downloaded any trouble codes ?

CG98XJ · 09-07-2009, 08:45 PM

i have no idea where the loud click is comming from because it only does it when im driving and its to hard for me to determine where it comes from. i do all of the routine maintenance myself and do keep a log of it. the oil, filter, and air filter all get changed about every 3 months. i have recently cleaned the throttle body and IAC and have tried injector cleaner. i do have a CEL andthe only codes it keeps throwing at me is for O2 sensors. i forgot to add that earlier. i have changed the O2 sensors twice since it has started happening and they keep going bad or are just giving a bad reading. so i figured it must be a fuel issue to keep having the O2 sensors go out like that. i am 100% positive its getting good air. i have also checked the TPS and it was good. i also checked the fuel pump relay which was good. i also have new (about 6 months old) cap, rotor, plugs and wires. all gapped correctly because i checked a few times, and all getting good spark. i even ran sea foam through the fuel, oil, and brake booster all at seperate times, and it didnt help at all. i am probably just going to bring it to a shop and see if they can tell me whats wrong. its so frustrating i havent driven my jeep in weeks. thanks for any help.

**CJ7-Tim** · 09-07-2009, 09:32 PM

It seems you should focus on the source of the Check Engine Light. If the codes are for O2 sensors and you are replacing the sensors with good quality, brand name replacement parts, you need to look at the wire harness that feeds the O2 sensors. If there are corroded wires, damaged wires, or damaged wire connectors and your data from the new O2 sensors is not making it to the ECU, you will have driveability issues.

CG98XJ · 09-08-2009, 11:31 AM

yes i do replace with good quality parts. im not cheap when it comes to stuff like that because i want it to work properly. ill take a look at the wires. if that is the case would i have to just replace the wiring? or if the wires are good do you have any suggestions as to what else could cause this? also where is my ECU located? thanks.

**CJ7-Tim** · 09-08-2009, 11:46 AM

Trouble shooting is a step by step process of logical problem elimination. You inspect and test either the most common sources of similar symptoms or the parts/systems most closely related to your CEL trouble codes. Start with the easiest and cheapest solutions before you simply start throwing random new parts at a problem.

You have a starting point with CEL and you have new 02 sensors, so the next logical place to look is the wire harness. The O2 sensor wires can get caught in the drive shaft or melted on the exhaust. The wire connectors can get corroded or damaged during sensor replacement. Also check the fuse box for burnt out O2 sensor fuses.

**Bane7962** · 09-08-2009, 03:37 PM

mine's doing the exact same thing
shes a 98 with about 153 on the chassis, and 90 on the motor
i did a new throttle body out of a junkyard (cleaned it first) thinking it was the IAC, and no help
i'll check the fuses, but im curious if you have yours fixed yet?

CheapJeep88 · 09-08-2009, 04:37 PM

I think I may have the same problem but what mine does is it bucks and sputters every now and then like the fuel pump kicked off for just a millisecond then its fine.. Also I noticed it does sometimes when i hit bumps? Can anyone help with this?

**Bane7962** · 09-08-2009, 05:18 PM

i havent noticed the bump thing, just going from a low RPM to a higher, she sticks sometime. no idea where the click's coming from, but its really getting old. she completely stalled out on me on the trails about 5 times. ive had at least one O2 sensor put in, the shop did it, so i have no idea if he used decent parts or not, but i pretty much trust the guy. also, the problem seems to be intermittent, that is, usually its fine, but every now and then ...
did the same seafoam, no help.
im tempted to take her to a dealer and let them look at her, but it'll probably cost an arm and a leg lol

CG98XJ · 09-08-2009, 08:02 PM

yea i have been trouble shooting this issue for close to a year now. i have went through every system that could probably cause it and have gotten no where. i never did think of checking the O2 harness. i have to wait till tommorow to do it. and no i havent fixed it yet. but if i do i will be sure to keep you informed. and after mine did it once on the trail about a year ago, i havent wheeled her since.

CG98XJ · 09-09-2009, 03:48 PM

well turns out i was on the right path. it is a fuel issue and i have a new pump on order. bane7962 you had a similar issue. i suggest you do take it to a dealer to make sure you know whats wrong. it will probably cost around 75$ and good luck.

**Bane7962** · 09-10-2009, 12:53 PM

thanks man, i'll probably take her in tomorrow and let you know what they say

5spdChopper · 09-10-2009, 01:24 PM

I had a problem with the fuel pump in my 88 XJ, but it became very loud before failure for quite a while. Made it easy to diagnose.

**Bane7962** · 09-10-2009, 01:28 PM

all i hear is the clicking/thumping, then she gets up and goes.
my local shop guy's had her 3 times, couldnt figure it out.
it just sucks because she's my DD, and its almost gotten me hit a couple times now