1. Re: Rear Window zippers!

    Hi fellow jeeperz, I am new to this forum, but I have a poblem. I just recently bought my 6 cyl and the bbd carb (no injection) stalls when I stop fast, if i stop like a g-ma it stumbles but keeps running. I am unsure of which vacuum lines I have to have but almost all of them have been removed. I don't really want to put the vacuum lines back on but I have to fix this problem. Also when it warms up it hard starts. Help???

  2. #2

    RE: I know it is personal preference but...

    Yeah, that's pretty much what every Carter carb is like. You're probably going to want to get a Weber 32/36 or 38 or a Motorcraft 2100 when you get the money. Sounds like someone already took out all the stock emissions equipment a la the "Nutter bypass" -- you may want to check and make sure they bypassed the computer the right way, just do a google search for "nutter" and check the schematic.

    I'm in the same boat as you and recently bought an 88yj only to find out that the carb is such a piece of crap that I'm going to immediatley have to shell out a few hundred bucks to even get the thing running right without flooding every time I have to hit the brakes. Furthermore, a new carb will give you a lot more horsepower and you may even get over 10 mpg, which means it might not cost you $10 to drive to the gas station.

    I've been researching which carb/ignition upgrades to do on that engine - you may check the threads that I've started within the last couple weeks to see what everyone has been saying. I'll probably be going with the Motorcraft 2100; there's a guy on ebay selling 2100 kits for yjs that will have everything you'll need to do the conversion.

    PM me if you need more info.
    88YJ - 4.2L, MC 2100, Custom Cold Air Intake, DUI HEI, LiveWires, 2.5\" Lift

  3. #3
    OK, i have also decided to shell out a few hundred and do the Motorcraft 2100 mod and I also will do the "Nutter Bypass" because the previous owner has removed all the vacuum system and stuff and trying to replace it all will not only cost me an arm and leg but will probably drive me insane!! Thanks for the info and I'll let you know how it went.
    To Err is Human, To JEEP is Devine!!!!

  4. #4
    Join Date
    Jul 2005
    "On the Mountian" Brightwood, Or
    I had a carter AFB that would gunk up around the accelorator pump & run out of gas that was a fun one to figure out.
    yours does sound like a vacuum problem though
    Dan & Stephanie
    His & Hers Jeep Wranglers \'95 YJ/\'99 TJ

  5. #5
    Join Date
    Feb 2003
    central pennsylvania

    Re: RE: Re: New wheels

    Very simple fix go to jeeptech.com there are step by step instructions to fix this problem (simple) just a plugged jet for the idle.

  6. RE: Emmissions for a V8ed CJ

    Hi-Ya texasjeeper,

    The fix for the BBD problem is available right here on Jeepz dot com. The article is located over in the "How To" section.

    Here is the link:


    One failing of the article is that the Jeep used for illustration did not have power brakes. On a power brakes equipped SWB Jeep, you might find that there is not enough space to remove the choke rod from the carb exactly in the way explained in the article.

    The work-around will be obvious.

    Hope that helps.



  7. #7
    OK, I have finished the motorcraft 2100 upgrade and WOW what a difference! This baby runs like brand new and the adjustments on this carb are easy as pie. HEI and exhaust next!!
    To Err is Human, To JEEP is Devine!!!!

  8. #8
    I would definately recommend the HEI upgrade. It's reliable and will make a noticeable improvement in performance. I replaced my stock carb and distributor with a motorcraft and an HEI, and the difference was amazing--POWER, gas mileage, better idle on flat ground and hills, etc.. Top that with a 4.0L head, and your motor will be pretty close to a 4.0L in hp but have better torque. After that I would go with a good header, a cam, higher compression...those inline sixes can really put out alot of power. I tend to get carried away with these things, though.

  9. #9
    Cool, good to hear.

  10. #10
    I ordered a DUI HEI, livewires, and a 2100 yesterday. Can't wait to do the install. Regarding the 4.0 head, I just saw that Hesco came out with a new solid aluminum head for the 4.2/4.0, not sure how much they want but might be worth looking into:


    Gary, what kind of header are you running? Only two I know of are Borla and Pacesetter, the former is expensive and I hear the latter is a piece of crap. Is it really worth the time/money to put in a header?
    88YJ - 4.2L, MC 2100, Custom Cold Air Intake, DUI HEI, LiveWires, 2.5\" Lift

  11. #11
    Join Date
    Oct 2003
    Wilmington, NC
    The DUI purchase was a good move.

    What size 2100 did you get? They come in different CFM ratings.

    Header? Oh yes, no question about it. That's the first mod you should make, followed by a good free flowing exhaust.

    While the factory head is very restrictive and is going to limit your ability to make power, you can still do alot with it. The whole engine is limited by the efforts they made to remain emissions legal. Alot of power can be had by simply doing the mods you are already planning and swapping in a little more aggressive camshaft that will extend that great torque curve up into higher rpms.

  12. #12

    RE: jeep trucks are the parts good for my yj

    Summit sells an aluminum head from Patriot Performance for $1500, and I bet Hesco will charge even more for an aluminum head. I personally don't think it's worth it. Clear Water Cylinder Heads sells rebuilt 4.0L HO cast heads on ebay for about $275 shipped. The core is only $75, and all heads have .010" shaved off which will bring your compression up about .2 (can be a good or bad thing). After looking at the stock cast iron exhaust manifold on the 4.2L engine, I would definately recommend replacing it with a header. I had originally planned to bolt a borla header up to my old motor, but pulled the engine before I got around to ordering one. The stock header on the 4.0L is pretty decent aside from its cracking issue, so I plan to just run that with my stroker.

  13. #13
    Junkpile, I got the 351 cfm carb and my ignition is optimized to the larger carb.

    How much trouble is putting a header in? Do I have to do much beyond pulling off the intake manifold and just replacing the exhaust manifold? I dont weld, so if that's required I would have to pay for labor.
    88YJ - 4.2L, MC 2100, Custom Cold Air Intake, DUI HEI, LiveWires, 2.5\" Lift

  14. #14

    RE: BABY!

    Gary, if I swap in a 4.0L HO cast head i would need a header for a 4.0, correct? I could still use the intake manifold from the 4.2, I think. So this would give me more options for which header to use.

    This means I would need to purchase a header for a 91-95 YJ? But the HO head is different, so I what kind of header would I need? Which exhasust?
    88YJ - 4.2L, MC 2100, Custom Cold Air Intake, DUI HEI, LiveWires, 2.5\" Lift

  15. #15
    There are some very complete write-ups out there on the web that I have seen. Do a google search and you will be amazed at what you find. Or search on here.

  16. #16
    I've read a couple of the write-ups, I'm just wondering if I need to track down a cherokee header or a 91-95 yj header...
    88YJ - 4.2L, MC 2100, Custom Cold Air Intake, DUI HEI, LiveWires, 2.5\" Lift

  17. #17
    With a 4.0L swap, the stock 4.2L intake manifold is reused. Both cherokee and wrangler headers will bolt up to the 4.0L head no problem. The stock headers from the 1987-90 Renix style Jeep cherokee's are less prone to cracking than the newer stock headers, and these older style headers have a place to hook up the EGR and O2 sensor.

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