1980 CJ5 jeep with 304 V8, manual

as you may know, just got it about 2 weeks ago...ran fine all the way back, ran good for quite awhile since its been here, the past 3 days or so its been acting up on me.

Sunday it wouldnt crank, jumped out looked at the filter and saw it wasnt splashing any in, thought it might be a fuel pump problem...but the problem with THAT is the fuel pump was replaced the DAY I got the jeep so i know its new.

now, i got it crank and run after some ether spray, got the fuel going again...the problem before that tho was the fact that when I drive after about 5 min of running it starts to sputter like its not getting enough gas to the carb. I have to let off the throttle and ease it back up to speed, if i try and punch it she just backfires and doesnt do much of anything, but let it settle and it goes back to idling fine.

sounds fuel related to me..and I makes the wholeeeee damn jeep bob up and down when its sputtering.

any ideas?

[Edited on July 29, 2008 at 5:05 PM. Reason : g]

7/29/2008 5:05:28 PM

just because it's new doesnt mean it cant be bad



did you clean the tank and replace the fuel when you replaced the pump? new pumps can fail pretty quick when trying to pump dirt

7/29/2008 5:10:14 PM

Sounds like a clogged carburetor. Can be a bitch to clean the fuel system if you have trash in your tank, but you'd want to start by cleaning the carb and seeing if it'll run again.

[Edited on July 29, 2008 at 5:12 PM. Reason : l]

7/29/2008 5:11:35 PM

^thats what this homeless dude that works for us said, that it was carb troubles...then again hes retarded and homeless, hard to believe him

whats the best way to go about it?


^^i didnt do the work on the pump but i know it was done when I saw it that day and picked it up

saw the receipt with the days date on it, the old one and the new one already installed

so i didnt do the work, think it may be a bad pump then aye? the filter looks clean tho...would it show up in there if it was pumpin all that crud?

[Edited on July 29, 2008 at 5:12 PM. Reason : d]

7/29/2008 5:11:37 PM

Is it one of those glass fuel filters? Usually you'll see some junk in it if there is a lot of trash in the tank, but they are worthless if you have a lot of junk in the tank.

[Edited on July 29, 2008 at 5:15 PM. Reason : l]

7/29/2008 5:14:20 PM

yea its a see thru one, and no, theres no trash in it at all thats coming from the pump, its clean and the filter/paper it self looks clean as well

7/29/2008 5:21:16 PM

it's probably got a sock filter on the sending unit in the tank, so you wouldn't necessarily be seeing anything in the glass filter. this sounds like a classic case of rust/junk/crud in the tank. when it's stopped, everything settles to the bottom. when you start driving, it gets stirred up and eventually plasters itself all around the sending unit blocking fuel flow. then the pump pumps itself dry. you stop, debris resettles. then it takes you spraying the carb to get the motor spinning enough to reprime the system.

i would like to clarify just one thing though. is this happening even when the engine is still fairly cold, or only after it gets up to operating temperature? i ask because it could possibly be vapor locking (gas boiling), those glass filters are notorious for it. when it starts sputtering, take a look at the glass as quickly as possible. you'll see the fuel boiling most of the time if that's the issue.

make sure your vent on the tank and/or the gas cap and all is clear and working right. i doubt that's it, but doesn't hurt to check.

7/29/2008 8:50:17 PM

how would that explain why it was fine on the 60+ mile drive back from Jacksonville?

wouldnt that stir it up as much as the past few days?

7/29/2008 11:34:44 PM

Probably depends on how you drove it. Cruising down the highway might not have the same effect.

And if you find out it's junk in the tank you might as well drop the tank and do it right. Filters won't do it. A new tank would be the way to go. You can hose it out, put some BB's and kerosene in there, and then drive around with it in the back of your other truck for a couple of weeks to try to clean it out though.

7/29/2008 11:48:26 PM

^^not so sure it has one. my 77 didnt. my guess would be to rebuild the carb, replace the gaskets and clear out your jets.

7/30/2008 6:44:37 AM

^^bingo. driving down the highway, it just chills along the bottom. turning, stopping, taking off, etc. like around town gets it going.

yeah, there's chance that it might not have one. it may have never had one, it has disintegrated into the tank, or someone has been in the tank before and took it off. common practice, they just figured the inline one was enough. i was just saying if it does, that's likely your problem and would explain why the glass filter is clean.

just drop the tank or at least pull the sending unit and check things out. i can assure you it needs to be cleaned even if it's not the problem after 28 years. replacements can be had cheap from jc whitney probably, or raleigh radiator can boil all the old junk out, and then apply a liner material to the inside so it'll never rust again and any flakes they didn't get are stuck to the liner.

[Edited on July 31, 2008 at 1:36 AM. Reason : .]

7/31/2008 1:35:10 AM

not to be captain obvious, but have you taken the line off the carb to see if you have good flow?

7/31/2008 7:56:10 AM