Need help diagnosing some problems

I drove the new XJ I just bought last week for quite some time tonight and came across a few problems I need help with. It is a 1990 4.0 with the automatic and 242? (part time and fulltime) transfer case. There are 140K miles on it. Also just so you know the exhaust is shot. Some of the problems I think may be from lack of backpressure but im not sure. First of all, sometimes when accelerating, the engine almost seems to cut out for a second before it takes off. Second of all, at some times when idleing or reversing then switching to drive quickly it stalls out. Third of all, when the engine is heated up and has been running for a while there are times when it does not want to accelerate and wont go over 2000 rpms. It sputters and feels/sounds as though it is misfiring or knocking or something rather. This is my main concern as it was happening on my first cherokee when I decided I should get rid of it. I am new to working on cars.

Also I will be changing the oil tomorrow (my first time ever changing the oil). Any tips? What all tools do I need? I also plan on doing a tune up within the next week. What all do I need to do for that? I have a basic mechanical knowledge so this shouldnt be too tough but I have no hands on experience (which was evident when i changed my alternator in my TJ lol). Also, aat 140K what are some things I should check/replace. I want to get this in good running condition so I can get it on the trails asap. Thanks for the help in advance.

Oh yeah.... sometimes my windshield wipers have a mind of their own and decide to turn themselves on and not shut off. There is also a lot of moisture inside the jeep. The carpet is pretty wet and I get a layer of ice on the inside of the windows. The headliner is a bit saggy.... is there any way it could be due to a leak somewhere in the roof?

My first thought...take it to a mechanic...you need more skills(ha,ha,ha.)

seriously, if you are going to do a "tune up" get some masking tape and nail polish and mark all the wires from front to rear of the engine 1-6 with masking tape, then mark THE OLD CAP with the nail polish the corresponding spot for each wire.

Use a phillips screwdriver and take off the distributor cap (note which way the #1 spot is located on the cap and put it back the same way) and remove the rotor or "bug" as it is sometimes called making sure to note that there is a slot in it which needs to be lined back up (it will only go on one way anyhow).

now put the new cap back on and put the OLD WIRES back on the cap. Now if you plan to change the wires as well just pull off one at a time and replace it as you replace the spark plugs.

I bought the plugs with the 4 electrodes and I did notice a bit of a difference but be advised that first plug was a knuckle buster for me... the boot didn't want to come off! The back one was a bit tight also.

You will need a 5/8 deep well socket, 3/8 ratchet, at least a 3" 3/8 extention, phillips screwdriver, masking tape and marker, nail polish and soap and water for your hand when your done - you'll need it!


Changing your oil:

MAKE SURE THE ENGINE IS COLD!

you can do this hot but if its your first time lets not...

get a large pan (something what will hold at least 2 gallons of liquid), you will need a good oil filter wrench so buy a decent one - you will be using it often.

CHANGING THE OIL FILTER:

Ok, take your oil filter wrench and go to the right side of your engine. right behind the distributor cap (where the spark plug wires go) is the oil filter...it is round, looks like a small canister and sits horizontal to the motor.

put the oil filter wrench on it and turn it towards the drivers side; it may take some convincing for it to come off they can be tough. Once you get it to move make sure the pan is under it to catch the oil from the fiter...then unscrew it and take it out...you could drop it into the pan but you have to hold onto it to unscrew it and it is not hot So just take it out.

Now wipe down the area of oil that got onto the motor and where the oil filter mounts. Get your new filter and put some of the old oil on the rubber gasket of the filter - not much, just enough to put a "film" of oil on it and then reverse the order and put it back on. Hand tight usually does the trick but if you use the wrench to tighten....then no more than 1/4 turn!

DUMPING THE OLD OIL:

First thing is a wrench... I have yet to change the oil on my 95 cherokee (just bought it and it had been changed) I would use a crescent wrench for this or a socket if you have one that fits. Loosen the bolt just until it drips and make sure the pan is under the drip.

NOTE:

the oil will come out of the pan in a pretty good stream and won't fall right under the pan so you will have to be ready to adjust the pan to hit the stream right off.


Now then; loosen the bolt and let it fall into the pan

Watch the drain and make sure it will hit the pan when it is done draining as well.

While that is draining get your beer or pop or tea in my case and wait till it quits dripping, once it has - reach in the oil and get the plug (this is why we do this cold...), wipe it and your hand off and put it back on TAKING EXRTRA CARE NOT TO CROSS THREAD IT!!!

RUN THE PLUG DOWN WITH YOUR FINGERS AND THEN TIGHTEN ABOUT 1/4 - 1/2 TURN ONLY.....

Now add in your new oil (taking into account your oil filter is empty) and check the level. It should be above the full level at this point but will drop to the correct place once the engine starts. Run the engine for 1-2 miniutes and shut it off and recheck the level - you should be good to go.


NOTE:

Straight synthetic oils are thinner and have a way of finding leaks in older motors... I would not buy it for that high mileage a motor. A blend might be better but I just run straight valvoline10-40 in all my stuff.

I did put the synthetic into my hot rod truck after rebuilding the motor and I noticed it seemed to rev up faster and have more response it seemed.

Your money spend it how you like.....


Good luck:

Jeepcherokee95

The stalling and hesitation sounds a little like what I got on my 87 from a bad throttle position sensor. Before doing too much, make sure that all connectors in the engine bay are clean. Unplug and replug each one you can find two or three times, to wdake them up a little. Do a very careful check of all vacuum lines, too.

The leakage could be either from the windshield, a bad well nut on the roof rack, or a crack in the roof around one of the gutter seams. You'll need to look carefully. Some of those leaks can be hard to trace. Look also for rust-out in the cowl vent area.

The problem with the wipers could be related to the leakage, if water is getting into the intermittent wiper relay or elsewhere. Again recalling my old 87, a chronic windshield leak from before I had it ate the circuit board contacts off the cruis control module, among other things.

Thanks thats very helpful. As for taking it to a mechanic.... I am only 18 so I want to learn the skills that will help me throughout my life. I know you were joking but I still wanted to let you know. I will be doing everything other than the oil change with my friend back at school. He is a mechanic..... not certified but still a mechanic (he works at a nursery on all of their trucks and machinery). He is also teaching me to weld!!!! But thats beside the point. I just need to know what parts to buy when I go to the auto parts store in town. Anyone have any ideas about the engine sputtering problem? Anyone had it happen to them?

You know what.... I bet that cowl problem is it. Come to think of it my cruise control is not working either. I will check all of the connectors and vaccuum lines later today. Thanks.

Hi,
I do not even own a cherokee yet, but I might be able to help you a little bit.

It is great that you have decided to fix it yourself, and learn along the way.

There are two very important points:

1. Make sure you buy a Chilton or Haynes car manual. (for your particular model) They sell these at every parts store and you can get them on line even cheaper. (max $20) These are THE best learning tool. If you get one of these you will be able to do every step below.

2. Since you just got the car it is very important to start with a blank page. This means eliminating any maintenance problems, before chasing down big ones. You do not know what was the last time any of these were done. So you need to do them all and write down in notebook the date and mileage when you preform them.

Change all the fluids! Every single one of them.
-oil
-differential oil
-transmission oil
-brake fluid
-radiator fluid
-power steering fluid
-and fill up wiper fluid.

Then change the following:
-air filter
-fuel filter
-spark plugs, and maybe even spark plug wires.

Then see how much of exhaust can be repaired with cheap tape (they have one for this purpose only at parts stores)

And finally try to do valve adjustments and check the timing.

Once you have all these done you will be able to locate problems much easier, and this is the best stuff you can do for any vehicle.

All of these require only basic tools (valve adjustment requires feeler gauge $5, and timing does require timing light, but you might be able to rent one of these for free from car parts stores)

I know this sound like very many steps, but it should only take you (as a beginner) one weekend of having fun.

Thanks guys. I have the haynes manual and am reading through that right now. It is great. Both of my jeeps are incapacitated right now. My wranglers alternator is fried and the battery also. Not a single store in the area has an alternator or can get one until monday. I have a two hour drive back to school before then. It sucks. The cherokee can make it im sure but I still need to do this stuff first.

What are the best (recommended) types of each of the fluids listed above that I should get? Also in what amounts do I need to get them? Do I need special tools to fill tranny fluid or differential fluid? Sorry about all the stupid questions. I am about to head out to the local autozone to get my stuff so any help is appreciated.

Well I just found the capacities and recommended fluids in my Haynes manual about 30 seconds after I typed that. But if anybody uses something that works great for them then please post up.

Not stupid question. To fill those up you need some way to pump the fluid in. Some fluids when you buy them in the store come with little pumps on top (like liquid soap), others you can "inject" and then there are some for which you will need an additional pump. Do not buy cheap ones they are not good. So either go with ones that have pumps on top of bottles or get a nice pump. You can get all these in synthetic, and that is always my recomendation.

Good luck, and let us know how it all went!

For those fluids, go to an auto parts store and get a suction gun. It's just a big syringe-like gadget that will suck up and squirt out a pint or so of fluid at a time. Some come with a metal gooseneck end, some with a piece of hose. Either works. The metal takes a curve better, but the hose leaks less. Cheap and effective. For thinner fluids, you just stick the hose into the jug and suck. For very heavy fluids you can take the end off and pour the stuff in, then put the end back on. Just make sure when you are finished using it to empty it properly, so that you don't contaminate one fill with the material from the previous one, and never use the same pump for both clean and dirty oil. I always hang mine upside down in a place where the puddle of oil is not a problem.

http://www.hartleige.com/page_4/suction.jpg

OK I did a tune up and oil change. I have to replace all of the other fluids still this week. I also have a new fuel filter to put in but the old bolts and clamps are too rusted.... do i need to cut them off or is there a spray that will help to loosen them? Also I am still having this sputtering problem. I have no clue what it is or where to start. Any more info on this problem?

side note: be careful not to get any rust or dirt in the fuel line when replacing the filter.

"Liquid wrench" is what i use on rusty bolts.

as for the sputtering- I cant really tell you spcificaly because this hasnt happened to me... yet (knock on wood). The ignition system or fuel system or both is probably causing that. could be a sencor though. im not sure. I would just take it to your local stealership. let them figure out what is wrong. Then fix it yourself with the assistence of your mechanic buddy becuase if you let them fix it is going to be a lot of money. and then they will find 10 other things that "needed" to be replaced in the process.

when you installed the new spark plugs you set the correct gap right?

I didnt install the new plugs, rotor, cap, or wires. They were all brand new when I looked at them. I will pull them out this weekend and make sure they are gapped right.