Fuel pump or pressure regulator problem

[toebee97]

So my latest xj has decided to get all temperamental on me. At first it would take 30-45 seconds of (2 or 3 cranks) to get the fuel pump to kick on. It's not kicking on when I turn the key on like it should. After cranking it for a while I can hear it kick on, and the engine will then fire right up. But today it decided to stop doing that for me even. This fuel pump was bought from Napa and put in about 2 weeks before I bought it, so about 3 weeks ago. It seems to be an electrical problem, but I have no testers to check. Does anyone know if there a relay under the hood that this runs through? Or could it be the fuel pressure regulator? I doubt that's it though since it stayed running once it started. Anyway, any help or input would be appreciated.

[W.O.R.P.Offroad]

regulator wont cause it to kick on or not. there is a fuse pump relay and thats what it sounds like to me.

[toebee97]

Thanks for the reply. That's what I was thinking, but I couldn't find any reference to a fuse or relay for the fuel pump in my chilton. Do you happen to know where to look? I don't really wanna start replacing stuff blindly, or drop the gas tank if I don't need to.

[ParadiseXJ]

On your RENIX the FP relay is here, in the 4 relay "Relay Center" above your coil under the plastic cover...if you still have the cover.

http://i168.photobucket.com/albums/u196/chasdwitt/ALL%20JEEP/2426393_11_full.gif

[toebee97]

Thanks for the reply, but it ended up not being the relay. The shop that the former owner had the fuel pump installed screwed up. They didn't drop the tank to replace the pump. So my guess is since there was less room to work in, they didn't notice that the sock on the bottom of the pump fell off into the bottom of the tank as they were putting the new pump assembly in. So needless to say it sucked up some crap and burned up that brand new Napa pump. When I called the former owner about it, he told me the shop was in Sheridan, OR, which is about 50 miles from me. I wasn't real interested in having my rig towed that far, so I just went to the auto parts store and got a new pump. But this time I made TRIPLE sure the sock was on it when I put it in. Haven't had any problems since. So someone else's negligence ended up costing me a whole day of troubleshooting and then replacing the pump, not to mention the 72 bucks. Just Empty Every Pocket, right?:rotfl2:

[4.3LXJ]

Glad you got it figured out

[toebee97]

Well guys, the panda is actin up again, and I think the fuel system is the culprit. Started sputtering here and there during acceleration in the beginning, but lately it's doing it when I turn too, especially left. Thought I was gonna have to push it down my street when I turned onto it tonight from work. As you know from above, I replaced the fuel pump last September. Like and idiot, I didn't change the fuel filter with it (I know :rolleyes:). So anyone think the fuel filter could be the problem? I already bought a new one, just haven't put it in yet. Or could it be the fuel pump going out again? I really don't want to drop the tank just to see if that stupid sock came off again. :banghead:

[LizardRunner]

well you did say that it sucked up some tank crud, so it would be a good idea to start with replacing that fuel filter. it also could be junk in the lines past the filter from the previous pump.

[xj4life2]

Check fuel pressure at the rail, rev it up and see what happens that should give you a good clue as to what is happening

[toebee97]

Well changing the filter didn't help. Still sputters, still dies when I turn left, and now it dies when I turn right too. AND I'm out 13 bucks for the filter. Kinda tearing my f-ing hair out here, I don't have the time or the money for this.

Edit: I'm gonna check the relay Charlie mentioned a few posts up and see what it looks like... well, they look fine, all seated good, no corrosion. I'm really hoping it's not the fuel pump again, that thing is a PITA to replace, and not very cheap either. Other than that, I'm out of ideas, short of replacing the entire fuel system lol. Guess I'll just hope it doesn't leave me stranded on my way to work today. :eek:

[4.3LXJ]

Find yourself a fuel pressure gauge. That will tell you the whole story. It sounds like you are loosing pressure for just any reason. Are sure you got the fuel pump in with no leaks?

[toebee97]

Find yourself a fuel pressure gauge. That will tell you the whole story. It sounds like you are loosing pressure for just any reason. Are sure you got the fuel pump in with no leaks?
That's what I was afraid of... nobody I know has a fuel pressure gauge. Auto Zone rents them, but my lovely fiance just spent the rest of my money without telling me first. And yeah, I'm fairly certain I got the pump in correctly without any leaks. Is it possible for that little sock to come off the end of the pump AFTER its installed?

Sent from my CyanogenMod Captivate

[toebee97]

Update... nobody I know has a fuel pressure gauge, and it's $150 to rent one at Autozone, but I'm broke so that's out the window.

So I got on the google box and started reading everything I could find about my symptom. Seems that the power steering can cause stalls while turning either way. It can be caused by a failure of the pressure switch which raises the idle of the engine while turning to compensate for the load of the PS pump. Problem is, it's usually only on 2.5L, and I have a 4.0L with no switch on the PS line. Out of curiosity I started it up and left it in park, idling between 800-1000rpm. Turned the wheel to the right, slight dip in rpm. Turned the wheel to the left, it dipped down to 100rpm and almost died. While turning either direction its kinda tough to turn the wheel. Checked the fluid, it's full, no leaks. Now I'm almost convinced the PS pump is the problem, maybe it's starting to go out? If I turn left with my foot OFF the gas, it will die, then I will have a hell of a time getting it started again, takes 4-6 good cranks to get it started again. If I keep my foot in it as I turn, it will sputter REALLY bad but stay alive and be ok. Don't know if any of this can be helpful to diagnose the issue, just passing on what I've read and tried today.

[4.3LXJ]

$150 to rent a fuel pressure gauge? Come on, I didn't pay more than about $20 for mine from Sears. But to get back to your question of stalling while turning. I was under the impression the vehicle was moving while doing this. If the rpms are dipping while idling and steering, then that would point to a failure of the idle air control. It just might need some cleaning. Your idle shouldn't be that high unless it is really cold anyway. Cleaning it is cheap.

[toebee97]

$150 to rent a fuel pressure gauge? Come on, I didn't pay more than about $20 for mine from Sears.
Yeah I know, I thought it was kinda high too. Then again, I did call the Autozone closest to my house, which is notorious for not knowing wtf they are talking about. They once told me 1990 cherokees don't have a heater control valve.:crazy:

But to get back to your question of stalling while turning. I was under the impression the vehicle was moving while doing this. If the rpms are dipping while idling and steering, then that would point to a failure of the idle air control. It just might need some cleaning. Your idle shouldn't be that high unless it is really cold anyway. Cleaning it is cheap.
It does stall when it's moving, I just was reading around yesterday on JF and a couple other places and it gave me the idea to see if it was doing it at an idle too, and sure enough it is. Funny you should say that the idle shouldn't be that high unless it is really cold... if the engine is cold or it's cold outside, and I just start it and walk away, in about 5 minutes it will creep from about 800rpm to 2500rpm+!!! So needless to say I'm gonna look into the IAC today, found a write-up on JF about it.
http://www.jeepforum.com/forum/f13/how-clean-your-idle-air-control-valve-756934/

[xj4life2]

Well here's my guess I would say the fuel pump is going out or the strainer is clogged, We have seen this a couple times and replaced the pump and it was fixed. I have also seen the baffels in the tank rot away and cause this due to the fuel sloshing away from the pick up during the turn. If it were me I would replace the fuel pump,If cleaning the IAC doesn't work

[toebee97]

Well here's my guess I would say the fuel pump is going out or the strainer is clogged, We have seen this a couple times and replaced the pump and it was fixed. I have also seen the baffels in the tank rot away and cause this due to the fuel sloshing away from the pick up during the turn. If it were me I would replace the fuel pump,If cleaning the IAC doesn't work
It better not be the fuel pump again, I just replaced the damn thing last september... and unless the baffles rotted out since I put the aforementioned fuel pump in, I'd say that's not it, because the inside of the tank looked great then. But I don't know I suppose it's possible. I've considered buying a brand new tank for it. But for now all I can afford to do is clean the IAC.

[toebee97]

Well, I cleaned the IAC. This is what it looked like before.

http://i275.photobucket.com/albums/jj289/toebee97/JEEP/IMG_20110628_140940.jpg

Used a can of carb & intake cleaner I got at Walmart and a $1 toothbrush to clean it. This is what it looked like after.

http://i275.photobucket.com/albums/jj289/toebee97/JEEP/IMG_20110628_140940-1.jpg

Noticed my T-body was lookin pretty gunky too, but I can't do anything about it till I get a Torx bit that big.

http://i275.photobucket.com/albums/jj289/toebee97/JEEP/IMG_20110628_141426.jpg

Runs fine, turned on the lights and heater and turned the wheel and whatnot, seems to adjust the idle to compensate just fine. Have not had the chance to drive it around yet to confirm whether it still has the left turn stall issue, I've had a few brewskies so I should probably wait till later or tomorrow. :drinking:

[xj4life2]

when your doin this clean the area inside where the IAC pintel rides.use a Q tip to get way in there.

[toebee97]

when your doin this clean the area inside where the IAC pintel rides.use a Q tip to get way in there.
Damn I didn't think about usin a q-tip... I just used a blue shop towel and twisted it up to get in the hole in the TB. Looked pretty good afterward. I cleaned everything I could reach without taking off the whole TB, seems to run a bit smoother. I have a really bad oil blowby problem so even if I clean it it will just get nasty again eventually. Been on the lookout for a rebuilder, but that's another story and another thread. :smiley-laughing021:

[toebee97]

Well I got a fuel pressure gauge from a buddy at work. Gonna hopefully get around to messin with it in the next couple days. Will post back when the results are in.

[toebee97]

Ok, just checked the pressure. When I first hooked up the gauge, a little gas came out but it had almost no pressure. Turned it over, had about 45psi, but was slowly creeping down, went down to 40psi in about a minute. Shut the engine off, pressure went all the way to zero in about 10 seconds. Shouldn't it still be under pressure after the engine is off? I'm no mechanic, but it looks to me like the pump is working fine, but I have a leak somewhere and the pump can't keep up. Kinda what I was suspecting, but now I'm almost positive. Thoughts?

[4.3LXJ]

Ok, just checked the pressure. When I first hooked up the gauge, a little gas came out but it had almost no pressure. Turned it over, had about 45psi, but was slowly creeping down, went down to 40psi in about a minute. Shut the engine off, pressure went all the way to zero in about 10 seconds. Shouldn't it still be under pressure after the engine is off? I'm no mechanic, but it looks to me like the pump is working fine, but I have a leak somewhere and the pump can't keep up. Kinda what I was suspecting, but now I'm almost positive. Thoughts?

Yes it should. There is a check valve on the back of the fuel rail I believe. If you have that new pump working right, it has one at that end. It should hold pressure at that end, and with a good fuel rail check valve it should hold pressure for quite awhile.

[Floridajeepcherokee]

If it stalls out at red lights and then won't start back up is it the iac?? It's getting worse but let it sit then it will start up. It's getting worse at first it would stall and start right back up. Here lately it back fires and stalls not necessarily at same time and won't usually start right back up but turn key off and wait or push out of intersection and it starts right back up....WTH?? Mechanics can't find issue or didn't find issue.

[Floridajeepcherokee]

I was quoted 112 dollars for fuel filter b/c it's also a regulator on a 98 jeep grand Cherokee so why is your filter reasonably priced near 10 dollars???

[Brasscatz]

Yeah, I would try cleaning the iac really really good first abd see if that makes a difference. I'm keeping my fingers crossed

Sent from my Samsung Galaxy S4 because my microwave couldn't do it

[4.3LXJ]

If it stalls out at red lights and then won't start back up is it the iac?? It's getting worse but let it sit then it will start up. It's getting worse at first it would stall and start right back up. Here lately it back fires and stalls not necessarily at same time and won't usually start right back up but turn key off and wait or push out of intersection and it starts right back up....WTH?? Mechanics can't find issue or didn't find issue.

Cleaning the IAC is always good. However if that doesn't do it, then it is probably your crank position sensor getting ready to quit completely

[Floridajeepcherokee]

Thanks, Does revving, placing in neutral, or backing out of accelerator prevents it from stalling mean anything?>

[Brasscatz]

I know revving would help the iac issue if there was one. Idle at neutral wouldn't as far as I know. TPS feels more like that issue, or even a possible bad connection on your NSS (neutral safety switch) or maybe even the switch itsself

[Carves]

I was quoted 112 dollars for fuel filter b/c it's also a regulator on a 98 jeep grand Cherokee so why is your filter reasonably priced near 10 dollars???


Earlier models used a common, cheap ... external ... filter.

Later models with the plastic petrol tank - use a, in-tank, filter, pump, and regulator assy -that most most places try to sell as a complete unit.

The pump and the little plastic, sock filter, can be sourced individually tho ... dunno about the regulator.

[Floridajeepcherokee]

I cleaned IAC, put Sea foam in throttle body and backed 2 screws in pcm out slightly. I had called Auto Zone about fuel filter and was quoted 112 for regulator and filter and told its under the hood but I didn't see it. I haven't looked under vehicle for filter yet.

[drakan1908]

I cleaned IAC, put Sea foam in throttle body and backed 2 screws in pcm out slightly. I had called Auto Zone about fuel filter and was quoted 112 for regulator and filter and told its under the hood but I didn't see it. I haven't looked under vehicle for filter yet.

Yours is like mine. The fuel pump,filter,and regulator is mounted in the tank and comes as a unit. I think you can replace the pump but it is recommended that it be replaced as a unit.

Sent from my XT907 using Tapatalk

[Floridajeepcherokee]

No filter on the rail?? That's crazy. Auto Zone didn't say pump though.

[Floridajeepcherokee]

Earlier models used a common, cheap ... external ... filter.

Later models with the plastic petrol tank - use a, in-tank, filter, pump, and regulator assy -that most most places try to sell as a complete unit.

The pump and the little plastic, sock filter, can be sourced individually tho ... dunno about the regulator.

What about 1998?? Stalling and back firing not at the same time. No inline filter whatsoever??????

[Floridajeepcherokee]

Sold jeep for parts vehicle after replacing ecm/pcm and alternator. The compression check tested low. Sorry i think I have a bad taste in my mouth for Jeeps, now.