bare minimum for vac. lines on 85 2.5

Hello all. I have a serious problem with my vacuum lines on my 85 wagoneer with a carbed 2.5. I have tried searching for the past couple of hours and have come up with only a little info that didn't help very much. I was told by someone that the bare minimum would be to keep the PCV(manifold vacuum connection to the valve cover), vacuum advance(ported vacuum to the distributor), manifold vacuum for accesories and tranfer case switch. I don't know much about vacuum lines but do all my own work. I have a diagram of the vacuum lines on the firewall of my jeep but need to know what vacuum line to keep and which ones I can get rid of to make my jeep run properly. This is not a DD but would like to keep my heat and accesories running good. I have select trac four wheel drive that runs off of vacuum. I just put in a used motor out of an 84 wagoneer and some of the vacuum lines do not match up with my 85. Is there a difference between the two? My jeep will start and idle great but as soon as I give it some gas or all gas it wants to fall on it face and die unless I let up on the gas and let it catch up with itself and than it will at least go down the road but there is no power to accelerate. It feels like it really wants to get up and go but something is holding the engine back. There is no backfire or missing when at idle or trying to get up to speed. Is it my distributor? I am at a total loss for what to do besides thinking that the vacuum lines are the problems. Please help with this if possible. Any advice or suggestions are greatly appreciated. Thanks in advance for replies.

I had an 84 Wagoneer 2.5L that acted the same way. I was at the dealership one slow Saturday morning and described the symptoms to the parts guys. The junior varsity parts guy chimed in "The carburetor's falling apart." Turns out he had the same vehicle, and the same problem.

I went home, pulled the carb, and found that -- sure enough -- the upper half was not well attached to the lower half, and the lower half was loose on the manifold. In fact, two of the four screws that are SUPPOSED to hold the upper to the lower were missing entirely. Can't imagine how it ran at all. Can you spell V-A-C-U-U-M L-E-A-K kiddies?

I don't think that it is my carb. I will check it out though. The carb was on there pretty good. We checked all lines and bolts on the carb when we were replacing the lines going to the carb. Is there someone out there that knows what the bare minimum on the vacuum lines are so I can get rid of most of the other vacuum lines that I don't need. Again this is my trail truck so I don't need to pass anything for the DMV here is Wisconsin. I just want a good running engine without all the BS! I have a diagram to follow for the vacuum lines just need to know the bare minimum. Thanks for the reply Eagle. Common 2.5 owners where are ya out there. Need the info for Thursday so I can get it running properly for the weekend.

Which carb do you have? Does it have the air mixing valves at the bottom? Reason I´m asking is, the vacuum diagram I´ve got for 84/85 4 banger looks amazingly similar to the set up on my old carburated YJ (4.2).
If you have the engine control module and don´t have the integrated Delco distributor. There really isn´t much you can do about the vacuum lines, short of major surgery. There may be something for you though, if it´s the same setup I have in mind. A simple (cheep) component change, that did away with most of the vacuum lines and worked wonders on my YJ.
Do you have smog tests where you are?
The Canadian, vacuum diagram, looks to be the simplest, in a near stock configuration.

I think that my carb is a 1 barrel Weber but I am not sure. I will have to look tomorrow. My jeep is about 35 miles from my home and work. I can only get a chance to get to it about every other day and the weekends. I am really stumped about the vacuum lines. I am trying to follow the diagram for the vacuum lines but the main lines are connected to other lines and which are connected to other lines and so on. I cannot find where my distributor vacuum line is supposed to start at. This is the first time I have had to mess with vacuum lines this much and I am very frustrated. Is there anyone out there who has the 2.5 and has taken their vacuum lines out to the minimum? Any help would be great. If someone out there lives around me and knows what to do with this I would pay for the gas and meals and a few beers if needed. Please help!!!

Thanks, Kim.

The 85 2.5L XJ runs a Carter YFA carb. Weber's area available aftermarket. The carbs are computer controlled and a PIA. Vacuum leaks are probably the biggest issue, but don't forget the automatic choke. The ground on the choke is notorious for getting flakey and the choke closing when you don't want it. Jut to try it, wait until the engine is warmed and then take a piece of safety wire and wire the choke wide open, If you see a performance gain you have a choke problem.

The used engine that I purchased is out of an 84 wagoneer. Is there any differences in the engine from 84 to 85? The choke was working fine when we looked at it while running cold to warm. I started it again last night with new oil, oil filter and new oil pan (old pan had a hole). I still have no power when I put it in gear but idles great without the vacuum line on the distributor. I just think that my vacuum lines are seriously messed up from the previous owner. there were some things that were not the way the diagram showed before I took out the original motor. Now that I have the 84 engine in the jeep things don't match up worse than the original. My original engine ran better than this before I took it out but had ALOT of smoke coming out the valve cover hole towards the back. OLD MAN, do you know what the minimum on the vacuum lines are for me to run on my engine so I can at least get the power out of it? I don't care about heat right now this is our trail only jeep. I need to get this ready in a couple of weeks to participate in some events with my club. I really appreciate the replies so far from everyone. This site is great for getting info. As soon as I get this problem taken care of my check for membership will be in the mail. Thanks again all.

Kim.

I replaced my 4.2YJ's carter bbl with a weber, never did get it to run right. If it is a carter they have a tendency to 'dribble' fuel thru the venturi's and run extrememly rich. I found out later on it would have been much cheaper to put a Ford 1 or 2bbl on it out of a boneyard than the $400+ I spent on the weber...

What ford vehicles came with the carb you are refering to Rich P? I am willing to try just about anything to get rid of all of this vacuum BS!!!!! I was reading some research from searching and I am leaning towards just getting a new carb and getting rid of the vacuum lines. Let me know please. Thanks.

Kim.

old_man has a good point -- I lived with terrible acceleration and poor performance for a long time with my 85 XJ, 2.5, 5sp until I finally wired the choke open. Finally after a proper analysis, I found that the problem was not the ground but the choke relay (inner fender near the starter relay). From your last post, though, I assume you have confirmed that the choke is opening fully and staying open.

WRT vacuum routing I'm not sure about differences between 84 and 85 but California and Canadian models, at least, are different from the 49 state configurations. I bought my Jeep new from a Texas dealer but apparently got a model intended for California with distributor using manifold vacuum. After 20 years of pure stock I just converted to a Weber 2bbl carb. I tried using ported vacuum for distributor advance but the Jeep did not do well, apparently not as bad as you describe, but acceleration was very flat. You might try manifold vacuum along with timing adjustment unless you know for sure that the 84 used ported.

With exception of distributor advance, as far as I can tell vacuum lines on these motors don't have anything to do with engine performance as long as they are not leaking and any unused ports plugged. My Jeep runs very well with vacuum to PCV and brake booster, manifold vacuum to distributor and 4wd transfer, and ported vacuum (currently) to climate controls and cruise. As soon as I am sure timing and carb are adjusted to best performance, I will add back as many pollution control items as make sense.

If you have a Carter YFA feedback or other computer controlled carb (don't know about 1 bbl Webers) you will need connections to the ECU but I am unaware of any vacuum sources that provide direct input to the ECU. Someone correct me if I'm wrong on this.

Thanks for the info Pelican. With everybody chiming in and giving me their thoughts of what to do is helping me piece together the problems and what to do about them. Keep the info coming everybody. It is very helpful. After I get everything figured out and running properly I will post another thread as to what to do in this situation. I am on a learning basis with this but I imagine that once I am done I will be an expert on vacuum lines on my engine. So please keep the replies coming. I have been searching the internet and have come across some info but not alot. Thanks to all.

Kim.

I don't have an answer about the differences in 84 and 85 engines, and I have not had my 85 2.5 since last summer, but I can offer the following observations:

(1) Don't worry about which vacuum lines you need to run accessories. Instead, plug every vacuum port on the carb and intake manifolds so there are no leaks. When it's all working correctly, you can start replacing stuff. Check the vacuum booster. Did you say yours had a vacuum advance? Is it working?

(2) The failure to accelerate may be the accelerator pump. Check it by looking down the barrel of the YFA, and with the choke open (so you can see), operate the linkage to open the throttle plate. You should see a stream of fuel like a squirt gun shooting down the barrel. If this is not happening, get a rebuild kit...the pump is in there.

(3) Check your float level and float valve - make sure they're letting fuel in.

(4) Check your fuel filter - a clogged filter will prevent high speed runs.

(5) Why not try the carb from the old engine?

(6) Is your ignition nice and fat? Is it timed correctly? Again, does the advance work?

Remember that on this early engine you actually have to time it using the distributor. You pull the vacuum advance line and a connector over on the drivers fenderwell by the multiple vacuum solenoids. Sorry I don't remember the timing degrees but it should be on your emissions plate on the firewall.

Sorry for the space between replies from me. I am working three jobs right now to pay for what I am doing to my jeep to get ready for Memorial weekend. When we first put the used engine in it took a while to start but once it started it stayed running. I put in the new plugs and it started right up and sat at an almost perfect idle. I could rev up the engine with no hesitation or backfire. No misses while at idle either. When I put it in to gear it stays running with no misses but when I push the gas down it will go but seems like something is holding the engine back from giving all power. Once in a while the jeep will feel like it wants to get up and go but then the feeling comes back like something is holding the engine back from releasing full power. I don't know if this helps out at all for you guys but this is what happens. The carb is bolted down solid. The choke works fine. Nothing wrong with the fuel filter or lines. I will not be around my jeep until tomorrow afternoon to try some new things. If anyone has more questions let me have em. I will be up for a while yet. Thanks for the replies from everybody.

Kim.

I went through almost exactly the same thing your going through with my YJ, 4.2.
Best advice I can give you is to make a copy of your vacuum diagram and then color the seperate loops.
EGR, CTO valve, TVS, delay valve and EGR valve are one loop.
The CTO valve is a dual purpose, it also provides vacuum to the charcoal canister and the associated parts loop. A vented gas cap and you can plug the works, mess with it without a vented cap and you are gonna either suck liguid gas someplace it shouldn´t be or put your gas tank under vacuum, both undesirable.
The distributor vacuum advance is provided from two directions, the carb (open throttle and closed throttle), and another vacuum loop in the vacuum resivoir circuit, it is controlled partly by the ECU and partly by vacuum in various places, depending on the configuration (the Canadian is the simplest).
My finding was, if you are gonna remove any of the ECU controlled vacuum solenoids, you have to remove the whole works or your gonna have some sort of serious problem. By my count there are 30, solenoids, sensors, switches and vacuum assoiciated items that are all interelated.
Just to maybe get right to the chase, flat accelaration after about 2500, was a disconnected vacuum resivoir line on mine (distributor wasn´t vacuum advancing) . It ran under the battery on the YJ and was stretched to run straight across a gap of about 18 inches, hanging in the air, I´d hit a big bump and the line would pop off of the vacuum resivoir.

Read this not what your looking for but related, http://www.off-road.com/jeep/258ignition.htm

Got the engine in and running great! Still have a couple of bugs to work out with the vacuum lines but after it warms up it idles great and has alot of power. I will post again when I have all the things written down and are in the proper order of how to do it or how I did it at least. I may have a couple of things off right now but it runs awesome and couldn't ask for a better running engine besides new. Only have a couple of vac. lines running the engine now and that is the way it is going to stay. It runs alot better without than with vac. lines. If any questions please let me know and I will answer them the best I can. Thanks goes out to all who posted. Info was greatly appreciated!!


Kim.