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Discussion Starter · #1 ·
258 won\'t idle smooth, Can I fix it?

My 1988 yj, 258 I6 is completely stock, I bought it a year ago and had the carb rebuilt at that time because the thing would'nt idle at all. Since the rebuild its bin idleing OK but not great, now I've been trying to smoothen out the idle. It seams to have a miss that I just can't get rid of, is there any hope?
 
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Discussion Starter · #2 ·
Re: 258 won\'t idle smooth, Can I fix it?

If you have confidence that the carb was rebuilt correctly, I'd look for maybe an ignition problem. Check the timing to make sure it's right. To time the engine correctly, you don't just remove and plug the vacuum like to the distributor, you also have to disconnect the electrical connection to the two vacuum switches on the firewall. Check out this web site for all you need to know about carbs, timing, setting the idle etc:
http://www.off-road.com/jeep/tech/258bbd/index.htm
Hope this helps.

Ralph...

Carpe Dium - to make every day count!
 

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Re: 258 won\'t idle smooth, Can I fix it?

check the ignition system, re check the carb.. and most of all check for cracked,missing,rotted, mis routed vacum lines or vacume leaks

Vacum leak thats my guess, get a good manual and check and replace all of the vac lines, its over 10 years old, they probably arent any good..

OzarkJeep
77 CJ5, in a bunch of sanded and primered pieces
 
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Discussion Starter · #4 ·
Re: 258 won\'t idle smooth, Can I fix it?

/wwwthreads_images/icons/tongue.gif
well and yet another 258 bbd carb failure!/wwwthreads_images/icons/frown.gif
clickable:
http://www.off-road.com/jeep/tech/258bbd/Major.htm
i fussed with mine since purchased in jan./wwwthreads_images/icons/mad.gif
i bought a new rebuilt carter by holly at checkers for $180 and runs perfect now!
i had gone through everything it seemed.
i took out venturi cluster and cleaned idle pick-up tubes. found a grain of sand in one. this was when it would not idle at all.
i always questioned the shape of the carb when i bought even though it was only 2 years old (rebuilt) with receipt from previous owner. it had a lot of rust on the exterior and the choke was rusted wide open and not working. jeep came from the coast in s. carolina.
anyway.....
if all else fails, do what i did. the money was worth it 10 times over!
good luck
steve
 

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Re: 258 won\'t idle smooth, Can I fix it?

I replaced BBD with a Weber 38 (I think a Motorcraft 2100 or 2000 would probably be better, as they are cheaper and run 50 cubic feet of air more per minute) and after I re-connected my snorkel it began to run like crap. I had to keep cleaning out the jets (on Webers you can unscrew the jets from each side and blast them out- wonderful design!) until it stopped messing up. Each time there was some dirt, oil, grease, and once even some plastic clogging the jets. The other culprit is usually the venturi bolts, which requires shooting carb cleaner into the top of the carb with the little tube, right into the bolt.

My Jeep is just a leaky submarine in disquise
 

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4,143 Posts
Re: 258 won\'t idle smooth, Can I fix it?

I replaced BBD with a Weber 38 (I think a Motorcraft 2100 or 2000 would probably be better, as they are cheaper and run 50 cubic feet of air more per minute) and after I re-connected my snorkel it began to run like crap. I had to keep cleaning out the jets (on Webers you can unscrew the jets from each side and blast them out- wonderful design!) until it stopped messing up. Each time there was some dirt, oil, grease, and once even some plastic clogging the jets. The other culprit is usually the venturi bolts, which requires shooting carb cleaner into the top of the carb with the little tube, right into the bolt.

On my BBD I did these things...:
Disconnected the electronic fast idle (or was it vacume?) when it wouldn't idle smoothly. Personally rebuilt the carb with a kit from AutoZone. Keep a good airfilter on it! Run some gas-additive carb cleaner ever month or so maybe, and squirt the jets and venturi bolts out whenever it starts to run a little off. I hope this helps

My Jeep is just a leaky submarine in disquise
 
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Discussion Starter · #7 ·
Re: 258 won\'t idle smooth, Can I fix it?

I think I've got the son-of-a-#@#$, thanks for the hints. I removed the pulse air system, good-by, and reset the choke, jets, fast idle, idle drop etc, and it seems to be working a hell of a lot better. I can actually start the thing and go into the house to let it warm up now. However I would like to know more about the weber and motorcraft carb replacements, Do they work on the stock intake? Do the vaccum and the other hoses swap one for one? Your comments are greatly needed. Thanks
 
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Discussion Starter · #8 ·
Re: 258 won\'t idle smooth, Can I fix it?

FYI.......When I had mine, I installed a GM HEI with a LOT hotter spark which made mine pur and dramatically increased MPG and driveability. I also purchased the Weber (ouch!) and found it to be more responsive and smoother. The BBD worked great when new but they lack in longevity and DO NOT tolerate much dirt. Hope this helps. Wayne
 
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Discussion Starter · #9 ·
Re: 258 won\'t idle smooth, Can I fix it?

The Weber should come with an adaptor plate and all the hardware if you buy the kit,about $350 depending on where you buy it.It was fairly simple to install and tune for me and I'm very average on mechanic work.My has ran well and has really shone after I did the TEAMRUSH ignition upgrade.My only question has been the use of a pressure regulator for the Weber.I've read that it will improve the performance but I've had no reply from Weber.I would use Weber if I had to do it again.I don't know much about the motorcraft rh
 
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