Well, you guys have probly heard it a thousand times, but here comes 1001!!!!
I took my 90 yj in to the local shop on tues. night to see why it was running so rich. It was blowing black smoke, and getting about 7-8 MPG. I called them today, and they said they pulled a couple spark plugs out, and they were black as night. They also said I may need a new carb. The whole original reason I took it in was because I didn't know how to adjust it. I searched the bbs, and the only stuff I came up with went something like this:
step 1: remove carter and destroy
step 2: install weber
step 3: find aluminum foot to replace lead foot after too many speeding tickets.

But I don't want to put a weber on it because it has to pass
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here in ohio. So, now my question is, How in the world do I adjust the darn thing, and could I need a new carb. It is a 90 as I said before with 93,200 mi. As far as i know it is the original carb. If anybody knows of a web site or ANYTHING that can tell me how to adjust the BBD, I will be forever grateful!!!
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Yes, you do need a new carb, and no, you don't want another BBD. A few people have gotten to know and tolerate them but they're the exceptions. Most hate them. You should also seriously consider fuel injection. Big bucks but it solves the problem easily.

If you can't do FI, maybe you can sneek a carb swap in there. Couldn't hurt to try anyway. A Motorcraft 2150 carb, adapter, and rebuild kit w/needed modifications could cost well under $100. I adapted the stock air cleaner housing (the one for power brakes) to the 2150 by cutting off the collar that fits over the carb and replacing with a wider one made from sheet metal. Snips, pop-rivets, and a little silicone sealant was all it took. Spray painted all nice, looks like it came that way from the factory.

In your case you'd have to Nutter it and try to keep hoses and things looking stock, but could be done.

Go Mopar MPI if you can swing the bucks... see mine
If thats out of the question you can find lots of used BBD's out there, I still have mine, don't know what to sell it for, used boat anchors don't pop up in the sale pages of my newspaper much. With the BBD it's not always the carb itself but all the rats nest of hoses hanging off it...You could have a vacuume leak well away from the carb and it will change how the carb runs...shoot on over to Off Roads tech section
for more info on how to cure your BBD blues. Another exelent article. Good luck.

Update: I went to pick up the jeep tonight, and guess what greeted my checkbook? A $150 repair bill!! [img]images/graemlins/thud.gif[/img] [img]images/graemlins/cussing.gif[/img]
Anyway, I know it could have been worse, but [email protected]!! The guy told me that he cleaned the carb, adjusted it, changed the oil and filter b/c it was contaminated w/ gas, put a new air filter in it, and I'm not sure if he replaced all or some of the plugs. The thing that gets me, though is that I just serviced the thing 200 miles ago, and I don't think it was running rich then. My question is, did I do something wrong? I used 10w40 oil, and NAPA filters, and the morning temps around here have been as low as 10 degrees. I drive it about 7 miles one-way to scool and back monday-friday, which is plenty of time to warm up and get the thermostat open. My theory now, though is that when I had it warming up in the garage on the coldest mornings was that the cylinders "wet stacked" like a diesel can do if the RPM's aren't high enough, but that may not be true, because having the choke on raised the idle. Anyway, I am confused somewhat, and also wondering how bad the bearings in the lower end are damaged. One thing is for sure, though, I'm not rebuilding the 258 if it lays down!!! This sucker will get a 5.0L mustang motor Baby!!!
In the meantime, anybody got any ideas about this thing? The mechanic also told me mortals can't adjust the carb on this thing, you have to have some sort of scanner. Is this true? Thanks
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I had a similar experience after having a "professional" rebuild my carb. As well as damaging my floats which he should have replaced, and also left me stranded after driving for two hours(the length of time it took for the floats to fill with gas sending scores of gasoline into and spewing out of my carb onto every hot surface my engine had), he left me with a permanent rich condition for which California is not putting up with. My CO and HCO are way high... Pretend I'm an idiot and use small syllables so that I'll be sure to understand. For some reason this carburator and all information pertaining to it seem to be in Japanese. OI!

i guess there is a way to plug in to the computer, but its so old it really wont tell you much, if it can tell you anything.

Get rid of it!!!!! My bro in law fought me to the very end. He would end up rebuilding that carb almost every 3 months. Finally i gave him an 80 CJ carter carb and he built that one and the jeep never ran so nice. If your worried about emission crap, just make it look like it is all there and working. The earlier cj carb looks just like the later one except it doesnt have the plug on the back of it. So noone would even know the difference, unless you told them.

You bearings will be fine, one short period of time running rich wont hurt the motor. 258's are a tuff bird and will go on and on and on.

You don't mention if you have a visual check. If they're going to look for a computer plug at the back of the carb, you have a problem. If not, look into AFI for a GM tbi system. They're real helpful and can sell you a real low buck TBI conversion. To stay carbed, look at weber or motorcraft solution.


Do a search. This has been answered before on this BBS.

I don't know what your state's laws are for inspections and emmissions. but I took my computer controlled BBD off and replaced it with a freshly rebuilt carb for a 1980 CJ-7. The rebuilt cost $150. I left the O2 sensor and its wire still there so that it would pass the visual check.

The non-computer BBD is easy to adjust and mine ran great for about a year and a half.