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John_R 05-30-2010 08:50 PM

Fuel Pump I'm thinking
I've been getting this cutting out problem that is getting worse now and thinking maybe there was something in the tank and/or the fuel pump is going bad...I tried doing some searches, but didn't find anything on somebody actually reaplcing their pump.

On my ZJ (5.9) when the gas level was low and I made a left it would cut out. This one is doing it in a straight line, low or full, doesn't matter. The ZJ was relatively easy to change, as I lowered the tank and cut a "trap door" in the cargo area for top access...

So, wondering if anybody has replaced their pump and I highly doubt chrysler would give us a trp door thru the floorpan? I may cut one, but not sure exactly where the pump is in relation, so a diagram and/or pics would be great!

John_R 05-31-2010 01:01 PM

Re: Fuel Pump I'm thinking
So, nobody has changed their pump?

I've about had it with this thing already and am kind of in regret mode :( I mean, I do my own work and don't mind, but add kraut electronics (I will not buy a german car because of it) and it's a PITA. Plus, there is no information out there for DIY'ers hardly; I mean, does anybody work on their own stuff anymorE?

Scottina06 05-31-2010 01:09 PM

Re: Fuel Pump I'm thinking
I do all my own work besides body work. But Ive never heard of anyone changing their fuel pump. Are you sure thats what it is? You have a it could be an electronic throttle thing or many other things besides the fuel pump. Did you try

John_R 05-31-2010 01:23 PM

Re: Fuel Pump I'm thinking
Yeah, that's the problem with this thing, is there are so many electronic variables, it makes for fun, lol...I'm just a little miffed at this whole thing right now, so don't mind my ranting :D

What makes me think it's the fuel pump is the other day, like an idiot, I went over a curb stop of sorts, where the car came right down on it (thinking I had more ground clearance, ugh) and *bang* right on the fuel tank skid area, I'm thinking...So, wondering if something got jarred loose or the electric pump itself (the brushes, or whatever); the bang was pretty hard.

Ever since thing (and it's getting worse), the car will totally cut out and even have a little backfire. It's possible it could be something else, but just really thinking the pump or pickup...I *really* don't want to experiment, as you can imagine and if there were a trap door to just take a look at it, wouldn't be so bad.

Like I said, I'm just really disappointed right now and don't feel like spending my holiday messing with this thing again.

For the fun of it, gonna reset the PCM and see what happens. You never know. It just upsets me that we have no access to many of the functions of this thing and forget the dealer!

Edit - yeah, looked at wkjeeps, but will again (btw - my comment was more places other than there, as it's pretty informative and has been a big help!)

Scottina06 05-31-2010 01:32 PM

Re: Fuel Pump I'm thinking
woukldnt it have bumped the rear frame rail or suspension before getting close to the fuel tank?

John_R 05-31-2010 03:19 PM

Re: Fuel Pump I'm thinking
It seemed to hit right around the center, but I guess a little closer to the front, so maybe you're right. Although, the 'shock' from coming down and transmitting is what I'm thinking (if that's even the case).

I reset the PCM and even pulled the fuel pump fuse/relay for a little while, just for the hecck of it. It seems to drive fine now, but am going to take it on a drive here soon to really test it out. Just weird and these electronics drive me nuts, mainly cause we don't have access to much of it, unless you have a scantool and those are $$$. Would love to have one though!

I don't normally rant about things like this and normally do all my own stuff. I could figure it out, but would be nice to know if somebody knew if there was a trap door (doubtful) or had some pointers to save some time, or whatnot.

I still hate german electronics :D but honestly, maybe there's not much on this...who knows.

Scottina06 05-31-2010 03:21 PM

Re: Fuel Pump I'm thinking
PM milous and see if he has any drawings or schematics of the tank

John_R 05-31-2010 03:30 PM

Re: Fuel Pump I'm thinking
Will do, thanks!

I am hoping it's not the case (the pump), but I would like to at least take a look in there, to be sure the screen filter thing didn't get dislodged (never know) or a bunch of crap in there, etc. Shame they didn't give us an external filter and so tempting to put on on there.

btw - I noticed on napa site they offer two flow rates, it seems. One is 48 gph and the other want to say 68 gph, fwiw. Wonder what the factory unit is. If it's lower, would be a good upgrade, along with an adjustable fuel pressure regulator.

Scottina06 05-31-2010 04:05 PM

Re: Fuel Pump I'm thinking
Two fuel filters are used. One is located at the bottom of the fuel pump module, the other is located inside the module.

Could also be a fuel pump relay

Milous 05-31-2010 04:36 PM

Re: Fuel Pump I'm thinking
Diagrams sent...

I would check for any codes.

John_R 05-31-2010 06:08 PM

Re: Fuel Pump I'm thinking
Thanks, guys...Yeah, milous did finally get a code on my way back after getting on it

DTC P0339 Crankshaft Position (CKP) Sensor Circuit Intermittent

Hmmm, wonder if it would be as simple as a loose connection, although the CEL only came on after I got on it and left the pedal down a little...then the CEL started to blink (remained blinking unless I coasted, then steady, then blink on the gas again), and my ESP automatically disabled (message on LCD) and a blink onece ever 30 seconds or so.

Maybe it's a timing thing then...dammit to me thinking it could've been a fuel pump issue and almost buying one :)

Milous 05-31-2010 07:07 PM

Re: Fuel Pump I'm thinking
1 Attachment(s)
P0339 PDF file attached.

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