I took the venturi cluster out and cleaned my idle tubes... Didnt see a whole lot of crud come out, but it did seem to help my idle.
Anyway, at this point... i feel like i'm talking to myself lol. If i get any kind of response i'd be extremely happy to keep this thread going so i dont have to bother anyone with a PM or start a new one. I've replaced the leaky vacuum lines, and cleaned the idle tubes, but the fact that the idle screw has to be very close to all the way in persists.
I'm not sure where to go from here. The parts of the carb that were exposed while cleaning the idle tubes were sprayed really well with carb cleaner, but it looked pretty clean overall (as mentioned before, the carb has a sticker that says "Re-manufactured Carburetors" on it, so i'm guessing the PO had the carter either rebuilt or replaced? Its still a carter though =/.
Buying a new carb isnt an option right now because of money, but i really do want to do that when the time is right.
So at this point should i count on a rebuild kit to solve the idle screw problem? Or are there other areas to trouble shoot still?
I'm not very good with the carters but I have good experience with motorcrafts 2100's. Do you have a vacuum gauge? You might want to pick one up. Then you can plug it in the "T" where the brake power booster plugs into the manifold. You should have about 19 or 20 on the gauge. If it fluctuates all around or you have less than 15 or so it would be bad leak some where. My motorcrafts runs about 2 turns out with 19hg. Do you have a digital camera handy. Take some pictures of your motor, you be surprised what people can pick out on here.
Hi Jon, the first thing to do is get all of the vac leaks fixed if you havenít already done so.
As to the two ports you plugged on the bottom of the carb (meaning throttle body) I just want to get some wording straight. Letís describe the carb in terms of fender side, block side, front, and firewall side. The port on the fender side front corner runs to the 4/10 switch assembly on the firewall and itís OK to plug that carb port. The port on the fender side rear corner connects to the air cleaner assembly switches and should be left connected to the air cleaner (See What Controls What in the link I provided before.)
On the firewall side of the throttle body there are two vac connections. The smaller connects to the choke pull off mounted on the block side of the carb and should be left connected. The larger immediately connects into a T which 1) on the downward side connects to the purge line on the charcoal canister, and 2) on the other side connects to the decel valve (first via a T) and then on to the PCV valve on the front of the valve cover. The factory originally issued the engine with an electronic valve between the PCV valve and the carb, hidden under the air cleaner. That was later removed in a recall but you may still have it; if so simply run a straight line from the PCV valve to the T and just let the switch dangle (out of service.) Clean out or replace all of the lines associated with 1) and 2) above.
If you still have the Pulse Air system connected, pop the air cleaner cover and inspect the connections (see the link on Pulse Air.) If theyíre rusty or full of carbon then cap off the Pulse Air check valves. The system wonít be functional anyway since youíre nuttered so it might be wise to cap them off anyway.
Now itís time to rebuild the carb and itíll probably solve your remaining problems. I know it was "rebuilt" at some time but nobody knows what itís been subjected to. Itís a very simple carb to rebuild and the rebuild kit comes with instructions. There are two ball bearing check valves in it (hence BBD) and just make sure that you place the larger one in the fuel bowl under the accelerator pump; the smaller is in the venturi cluster as youíve already discovered. Use a carb cleaner with an injection tube and clean every orifice and channel, making sure that when you squirt it in one end that it comes out someplace; then let it soak for a half hour or so and blow it out. If itís really dirty do it twice; if thereís ever a time to be obsessive/compulsive this is it Ö "Cleanliness is next to Good Performance."
If you feel uncomfortable with this, then simply disassemble the three bodies of the carb and work on one at a time. Start from the bottom up and that way you wonít have a lot of parts laying around. Retain each gasket you remove so you can match it to one in the rebuild kit, and simply service it out from bottom to top. When you remove the stepper motor be careful as thereís a small coil spring between the motor and the body; donít lose it! Remove the idle mixture screws and springs from the throttle body and clean everything. When you reinstall them gently seat them to bottom and set them at 2 Ĺ turns out; this will get you closeÖyou can check your spark plugs in a couple of weeks and adjust accordingly --- or use a vac gauge to tune them precisely but thatís a later topic.
That should do it. Let us know your progress or if you need help. I suspect that after you get into the rebuild youíll be amazed at how simple it is!
Unfocused, thanks so much for the detailed response. Its so much easier to go out there and tackle problems when i have someone who knows what theyre talking about giving me feedback, and a confidence booster! The information you provided about the carb/throttle body ports will be really helpful, as i'm learning as i go and get overwhelmed trying to process everything by myself.
So ill go out and mess with my vacuum attachments to correct any faulty plumbing i may have done. And i'll also take ChevyBlazer's advise and try to get some pictures up. To answer your question Chevy, no, i do not have a vacuum gauge. Sounds like something i'd benefit from though, if it fits into the budget this week ill go pick one up.
One thing i didnt hear back on is the leak i seem to have in the manifold. When i sprayed carb cleaner along the screws and seam the engine seemed to pick up quite a bit. I tightened the screws as much as i could, with not a lot of change. I'm going to keep getting rid of my other, easier problems but in the mean time if i could get a bit of input on this that'd be cool too.
I'd also like to hear about other people's idle screws. As said mine is cranked almost all the way tight, the spring is a pretty tight coil. What do yours look like?
And last, to address the rebuilding of the carter... i think i will try to tackle that. Thing is its my daily driver and i have work early in the morning, plus its my first time completely taking a carb apart. So, i think ill wait till this weekend unless i have a full day sometime to work on it.
Thanks again guys for getting back to me, it helps me a lot
PS Joe203... I'm glad at least someone's 88 is running well . Maybe after i get all this stuff with my carb and vacuum hoses figured out i'll try that ignition system. But thats a ways off on the list lol.
You might have to replace the gaskets for the intake and exhaust manifold. Over time the intake on the 4.2 wears against the engine block but the exhaust manifold doesn't usually wear. And since the same bolts are used to hold the exhaust manifold and the intake what happens is the exhaust is thicker and doesn't put enough pressure on the intake when you tighten them down. So good gasket companies like FelPro sell you the correct gasket to fix that problem. They have a two piece gasket. 1 for the exhaust and 1 for the intake that overlays over the exhaust one. This Adds the thickness back to the intake so when you tighten the bolts everything sits evenly against the head. (kinda hard to explain) so here are a few pictures of what I am talking about on my 4.2. Pictures worth a thousand words ! I run this felpro gasket and it has been great..no leaks. I will see if i can find the part number for the gasket set0
Awesome chevyblazer! Thanks for that. That, i believe, is playing a hige part in my vacuum issues. Like i said thats where i noticed the biggest rpm change when checking the area with carb cleaner. The pictures are perfect, just what i needed.
This something a novice like myself could handle? I dont have a problem doing these things myself, i actually enjoy it quite a bit. But i dont wanna get myself in over my head.
+rep to you and unfocused for sure.
An additional note. It rained on the way in to work and i had no starting problems, the jeep ran pretty good. I'm hoping this means i at least have solved that issue... thanks to you guys.
Anyway ill keep you guys updated, youre my heros.
So i just got home from work and the jeep did something i read was called "dieseling". Thats the second time its done this, it did it for the first time yesterday. For those of you who may not know the term, its when you turn the key off and the engine keeps running/stumbling for a while.
Mine stumbled, pretty half assed, for about 1.5-2 seconds then shut off. This is the same thing it did yesterday.
I read it could be from timing (mines at about 9*), Carbon build up (very possible), or a few other things. Just wondering if anyone, based on my other problems, could give a good guess as to what may be causing it in my case. My guess would be a carbon build up, since my carter is due for a rebuild this weekend.
You should be able to do the intake and manifold gaskets. the hardest part is just making sure you can reach all the bolts. It's not a bad job. No special tools other than a torque wrench and making sure they are torqued in the right pattern which can be found in the service manual or chiltons or haynes book.
Hi Jon, just read your latest post and Iíve got to say some things which may seem harsh but will ultimately pay big benefits, and please donít take it personally.
First, go buy a Chiltonís or Haynes manual for your jeep. Either will be immensely helpful in terms of precise communication on the forum and will save you a lot of cash in the future, guaranteed.
Second, a good practice is to always fix known problems first. You already know that you have an intake manifold leak which is allowing air to enter the cylinders and bypass the carb. I can assure you that no carb on the planet will function properly with such a leak. You ask how far the idle screw is turned in, and why dieseling happens and ignore the significant problem.
Thatís not unlike asking why it takes so long for your toilet tanks to fill after flushing when the water line to your home is gushing like mad between your home and the street Ö you have low water pressure. You understand water pressure and itís logical to you. Carbs operate on vacuum, the flip side of water pressure, and your vacuum based carb is trying to operate with a leak "gushing (sucking) like mad" between it and the street (block) Ö you have low vacuum which prevents the carb from functioning properly.
You asked about whether you could replace the intake/exhaust manifold gasket by yourself and Blazer gave you some very good information; but nobody really knows whether you can do it yourself or if weíd just cause more trouble. You found two very loose bolts on the rear of the manifold and snugged them; perhaps others are loose as well and itís not necessary to replace the gasket - just some simple maintenance.
The following is from the FAQís Sticky section at the top of this forum in post #2:
Intake and Exhaust Manifold Retaining Bolts/Nuts 1989 Only
Nos. 1 and 2 - 30 ft-lbs
Nos. 3 through 12 - 23 ft lbs
Intake and Exhaust Manifold Retain Bolts/Nuts All Others
Nos 1 through 5 and 8 through 11 - 23 ft-lbs
Nos 6 and 7 - 17 ft-lbs
The issue here is that you donít know what bolt number 4 is, and thatís why either of the manuals are valuable. Either WILL save money, and only about $20 or so, available at most major auto parts stores. It may be that you donít have to replace the gasket and simply need to snug it up; if you donít have a torque wrench perhaps you can borrow one or have a friend with one who will help, or Sears has some very nice ones at very reasonable prices Ö itís something youíll need along with a vac gauge (about $10.)
So hereís a little gift for you for the coming weekend, for me having been so nasty and harsh:
I understand Unfocused... i do lol. I didnt mean to ignore the big problems, but i cant do anything major until the weekends usually, as my schedule doesnt allow. I was just asking questions, that in my head, may or may not have been related to the leaky manifold.
You're right though, that should be the first thing i tackle and see what problems still exist. I think i'll take the jeep out to my dad's this weekend and use his torque wrench and expertise and see if we cant get the leak figured out. Ill get myself a good manuel too, i dont know why i haven't yet.
On a side note, i did my first u joint replacement last night ... you should see the old one. I'm not sure how it was still holding on in there.
Anyway, thanks, as always for the help guys. No offense taken, i'm glad you would take the time to explain why my questions are stupid instead of just seeing the stupid questions and ignoring my thread lol.