Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
88 cherokee 4.0
01-03-2014, 11:55 PM
Post: #1
88 cherokee 4.0
Here is what i've learned so far. 1988 is not an obd1 or obd2 system for jeep, its a renix system, so being this system I can not pull codes to help me look at malfuctioning sensors or anything else. It starts fine but when it warms up it putters, misfires, and stalls. Sometimes it feels like its out of timing.
Here is what has been done.
Distributer.
Sparkplugs
Wires.
Cranck sensor.
Coil.
I don't know what else has been done, as my buddy bought it like this for cheap. I've checked timing and it seems right. I checked #1 piston up and dizzy is in the right spot. Can the timing chain be off by a tooth or so? Should i check other things before i start tearing into it. I'm really stuck on this one and someone else tore into it before, and i have no idea whats been done to it but what i did. Any info will be greatfull, thanks in advance
Find all posts by this user
Quote this message in a reply
01-04-2014, 12:27 AM
Post: #2
RE: 88 cherokee 4.0
When I only know part of the history and someone else has had their fingers under the hood I like to stick with the basics. You said, “Plugs, Wires, & Distributer.” That means; even if I was the one who did those things, I would still check the firing order one more time. Does it have vacuum issues? Weights in the distributor? Temperature sensor telling the computer that it’s cold and flooding it out? Proper fuel pressure? Did you check the timing with a light & using the proper procedure? Is the exhaust restricted?

Without being there to look for myself I can only point out a bunch of things that get overlooked. Please let us know if any of that helps.

Thanks for using the forum,
Garner

Interested in Mining? Look here: Coal Mining, PA
Visit this user's website Find all posts by this user
Quote this message in a reply
01-04-2014, 12:37 AM
Post: #3
RE: 88 cherokee 4.0
Weights in the distributer? What exactly is this. Yes I've checked the firing order. You sir just mentioned a whole lots of other things I can check. And yes it has lots of vacumm leaks, every time i find one I replace the hose. I also didn't think about the temp sensor having anything to do with it since the fans are wire direct with switch. It is work in progress since i work over the road and tinker with it on the weekends. If wife permites it. Lol
Find all posts by this user
Quote this message in a reply
01-04-2014, 11:33 AM
Post: #4
RE: 88 cherokee 4.0
Many vehicles had two small weights each with a spring attached right under the rotor. As the distributer turns faster centrifugal force flings the weights out to adjust the timing. This was on older vehicles but it is easy enough to check for. If it has them they can stick, bushings wear out, springs get weak, etc.. Repair kits are easy to get.

Since you say that you have vacuum issues, that would be the place to start. Vacuum leaks reek havoc on an engine. Get them all fixed and if you still have a problem it will be much easier to deal with.

The temperature sensor sounds like it could be a part of your problem. If someone was fooling with the circuit that would be an indication that there was a problem. Keep in mind that most vehicles have 2 temperature senders & some have 3. One sender is for the dash gauge or light. It usually only has one wire going to it. There will be a second one for the computer & some had a 3rd for the fans. They will have several wires going to them. There will also be a relay in the fan circuit that you will want to check. Get that system back to working properly even if it isn’t the source of your current issue. But I am guessing that it probably is.

Please keep us posted as wife permits!

Thanks for using the forum,
Garner

Interested in Mining? Look here: Coal Mining, PA
Visit this user's website Find all posts by this user
Quote this message in a reply
01-04-2014, 01:56 PM (This post was last modified: 01-04-2014 01:57 PM by Rupe.)
Post: #5
RE: 88 cherokee 4.0
Let's back up a moment and talk about when it quits. This would be the time to check things to see what's changed. I mean, it starts and runs but the problem comes in after it warms up, right? The timing chain will NOT change with temp so if it runs well enough cold you can rule that out.

On some of these older systems the dist advance vac goes through a gadget that screws into the water jacket and changes the vac depending on coolant temp. They can go bad!

You didn't say if this was throttle body injected or one of those electronic carbs that were so problematic. Most times (even back then) the issues were all about various o-rings that went bad or the mix solenoid failing. IOW, if it fees like it's starving for fuel that's a good place to start. (after replacing ALL of those 25 year old vac lines)

BTW, if it has advance weights in the dist you can usually get a feel for that part working by grabbing the rotor and giving it a twist. It should move maybe a half inch then spring back when you let go. You can do a test on the vac advance to see if the diaphram is ok by moving the linkage with your hand and blocking the port with a finger. It should hold till you remove your finger then spring back. Obviously any signs of rust or these parts not moving will be a clue. Only going here because you didn't say if this was a new or used dist.... and new could still be bad.
Find all posts by this user
Quote this message in a reply
01-27-2014, 09:42 PM
Post: #6
RE: 88 cherokee 4.0
Update.
After all the headache with replacing all vaccum hoses and pcv valve problem solved. It was a vaccum problem somewhere. Could not pin point exactly where since almost all the hoses where no good. But replacing them all was a good thing. Thanks for all the info and patience. I got it fixed, thanks again.
Find all posts by this user
Quote this message in a reply
01-27-2014, 10:32 PM
Post: #7
RE: 88 cherokee 4.0
Glad to hear you have a handle on things.

Also glad it was rather simple and in the long run I think anyone reading this will see how easy it is to "get the blinders on" and overlook basics when we are facing a disaster. (or so it would seem) We can all learn something from that, including me!
Find all posts by this user
Quote this message in a reply
01-28-2014, 10:38 AM
Post: #8
RE: 88 cherokee 4.0
Glad to hear that you got the main issue fixed. Thanks for taking the time to let us know! Now you should look into that messed up fan circuit.

Thanks for using the forum,
Garner

Interested in Mining? Look here: Coal Mining, PA
Visit this user's website Find all posts by this user
Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)