I feel your pain - really, because my 258 does the same thing, just not as bad. I rebuilt my Carter Carb myself, and it runs a bit smoother. If you rebuilt the engine yourself, did you put all the vacuum hoses on right?
What I can't figure out on mine is if it's getting too much fuel (flooding), or not enough (starving). I put in a new fuel pump and filter, which I assume you did as well, and no change...

Jedidiah Smith
1980 Jeep CJ-7 I-6, 258 stock for now

 

Before I killed my 258 which had the Carter carb... I put in a manual choke and was able to deal with the idle problems that way. Good Luck.

 

Did you but your heat tube on that warms up with the exhaust so the carb get warm air at first start up. Is the choke working. My brother in law had the same problem until i relized it didnt have that flexible air heat tube (or what ever they call it)>

 

Sounds like a vacuum problem.

82 cj-7,258,hei,weber,np435,D-300, superior axles

 

Rylan, your 258 is an inanimate object, it can't choose, by it's own free will, to run or not run.
Direct your anger towards the source of the problem, the "so called" mechanics who work on your engine.
I currently maintain 7 258's for myself and family members and have zero problems!
An engine can't choose to run good for me and not run good for you.
When all its systems are functioning properly an engine has to run good, it doesn't have a choice,
fuel, compression, and ignition causes an explosion in a confined place with only 1 place to go, it moves the piston.
Assuming all else is good, the fuel system is the usual culprit for the symptoms you describe.
Here's what I do , rebuild the carb, disable the stepper motor, check the choke pulloff for vacuum leaks, eliminate all vacuum related emmission controls, the only vacuum lines going to the carb are the dist. advance,the PVC, and the EGR is optional. Check the vacuum advance for leaks and tighten the intake manifold, the rear bolts always loosen on me. Make sure the choke is working right. In other words eliminate ALL vacuum leaks.
If your fuel system is clean, freshly rebuilt properly with no vacuum leaks it has to work right , it does not have a choice.

CTjeepnut

Funny thing is, the more I practice, the luckier I get

 

check this out:http://www.jeeptech.com/engine/carter.html

/wwwthreads_images/icons/cool.gifhttp://members.home.net/paul5696/wwwthreads_images/icons/cool.gif
Paul's Datsun Project
79 Datsun p/u 620

 

Rylan, all I have to say is to check ALL of the vacuum lines and make sure there are no leaks.
Replace them if you have to.
If none of this works for you and you are looking for a fairly easy fix for your problem I would look into the manual chokes.
I know it might look kind of odd on your jeep, but if it makes it work properly then I would go for it.
On my Willys I just start it, set the choke at a given position, let it run for a few minutes and then get off to wherever I need to go.

One thing I did to the Willys is I disabled the motor driven fuel pump and I put on an electric fuel pump.
This will always keep between 2 P.S.I. and 4P.S.I of fuel waiting to be used at your earliest convienience.
This last weekend I climbed a hill that is very rocky with a few ledges.
With the normal fuel pump it would stall when the motor started idling slow because the fuel pump was not going fast enough for it.
With the electric fuel pump it just idled right on up the hill like it was no sweat off its back.
Anyway, I hope this helps you out.
Take care and happy jeepin'.

"I see." the blind man said to the deaf woman./wwwthreads_images/icons/wink.gif

 

Is your Emissions Canister Hooked UP?.. Everyone tells me without this central control the engine will never run perfectly? Somehow its like a central vacuum port. Maybe if you hooked all the emission crap up and ran new vacuum lines you would see a big difference?

Muddynut
/wwwthreads_images/icons/cool.gif'79 CJ7 "Issues"-304-35s/wwwthreads_images/icons/cool.gif

 

There's not much left, if you've done all that.

1) Make sure the choke is closing when it's cold, and opening when it warms up.

2) Do the typical tests to see if the throttle shaft bushings are bad on your "rebuilt" carb - a lot of cheesy rebuild shops won't replace them.

3) I installed a permanent vacuum gage under the hood of my Jeep - it's probably the most important tool for an inline 6 that's prone to vacuum leaks. You should have a steady 16-22 in Hg. (mine's about 20) at idle.

4) How new is your fuel pump? It could be not supplying enough fuel.

5) Fuel filter in good shape?

6) What is your ignition situation? Did you do the "take the computer out of the loop" thing when you put on the non-stepper carb?

Bottom line - I still say that any half-complete system will not run well. When I put the weber carb on my 258, I left as many emissions things connected on my Jeep that I could, and it ran pretty well - way better than that BBD ever did. Then I did the nutter, because the computer was still varying the timing a little, and b@stardized the whole system, and it ran like crap. Then I put in the HEI and haven't looked back since. Weber, GM HEI, EGR, PCV, and it's great. /wwwthreads_images/icons/smile.gif

Good luck, the 258 is a nice motor, but a half-together system will never run well, in my opinion.
Pete

88YJ, 4"susp, JKS 1.25" body lift, 33"BFGMT, 9000# winch, homemade rear tire carrier, reb. 258, 999 auto, 4.10 axles, weber 32/36 carb w/adj. reg., GMHEI, CJ dash, ...and one moonguy/wwwthreads_images/icons/cool.gif