I just had my first XJ dropped off at the house. 85 Cherokee Pioneer 2dr, 2.5L Auto 4wd. Got it from a friend at work for little to nothing Trying to resurrect it since it has been sitting for about six years. Leaky fuel tank, peeling clear coat but solid everything else. Previous owner parked it because it wasn't accelerating and barely running.

I put in a new battery, cranked on it a little while adding gas to the carb and it hit once. After that I replaced the plugs and coil because the spark was more red than blue. Spark still looks the same but a little stronger I think. I had to hook up the jumper cables from my truck to it while cranking because after about 5 tries the starter drags and the volts fall to about 9v. I cranked on it pretty good again Sunday and sometimes it would try to hit, where it would spin faster like it was hitting a little but just not enough. Tried even a little shot of ether but that did nothing at all, didn't want to use any more because I didn't want to damage anything.

Going to pick up a compression tester this week to check that. Not sure if I need to go with new cap and rotor or not to improve the spark. Will also pull the carb and see how gummed up that is and to make sure I didn't suck any water up from the leaky fuel tank.

This would be OBDI I believe, so would that have a CPS I need to check?

I have worked on several Fords before (first vehicle was 71 F100 I had to build an engine for before Dad would give it to me a long long time ago) but not sure how things work on the Jeep.

Anyone have any other ideas of where I should go to bring this beauty back to life?

 

I would start with the carb - today's gas is questionable after 6 months, let alone 6 years. Also, clean your cable ends and other electrical connections. Hopefully someone will be along who is more familiar with your year/engine.

 

I would start with ground refreshing, including that crappo firewall ground strap. Bth ends of the battery cables sound like they could use some attention also.

Renix Ground Refreshing
The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, failed emission tests, and wasted money replacing components unnecessarily.
The components grounding at the dipstick tube stud are:
Distributor Sync Sensor, TCU main ground, TCU “Shift Point Logic”, Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff.
The factory was aware of the issues with this ground point and addressed it by suggesting the following:
Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.
Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.
While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely.
Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.
First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4” socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.
A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18” long with a 3/8” lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116.
A further improvement to the grounding system can be made using a #4 cable, about 10” long with 3/8” terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115.
For those of us with Comanches, it’s very important to remove the driver’s side taillamp assembly to access the ground for the fuel pump. Remove the screw holding the black ground wire. Scrape the paint from the body and corrosion from the wire terminal. Reattach securely.
If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price.

Revised 03-04-2013

 

Do you see a Motorcraft ignition module under the hood? I believe '85 was the last year those were used. If you've worked on Fords then you know they're problematic. Look at the back and see if the potting material is oozing out- that's a sure sign it's overheated.
Agreed with checking the compression and cleaning/rebuilding the carb, also check for rotted vacuum lines that might be causing a big leak and make sure the fuel pump still operates. Something was wrong with it when it was parked 6 years ago, sitting probably hasn't helped.

 

I will look more closely at the ignition module, seems like it had AMC on it but was similar style to the Ford one mounted on the fender just above the coil.

I have already replace most of the vacuum tubing after finding some that would turn to dust when you touch it. I still have one very tiny one coming from a 4-way rubber block near the front that I can not figure out where it goes yet. I also need to new rubber grommets for the front and rear PCV ports, these are totally shot.

Age is mostly what is wrong with this jeep, as I know the original owner probably almost never drove it over 45mph and it still only has 142K miles on it. Found just a little rust in front of the rear wheel wells but nothing major. Interior is still in great condition, just missing the headliner.

 

AMC bought ignition parts from Motorcraft. I believe the modules interchange with the Ford 300-6. So do the distributors on the AMC 258

 

I imagine the carb has some varnish in it but otherwise the fuel system was dry from having leaked out. I put about a quarter tank in it and after a week it is empty again, can even watch it drip from the hole in the plastic shroud on the tank. I think it is the 13.5 gallon tank and will need to pick one of those up. Advance has one for ~$140 I wonder it that is good or too high. Anyone know if it can be upgraded to the 20 gallon tank?

Going to clean the cable connectors also. Cruiser54, would the 4cylinder also have that grounded dipstick connection?

From other searching it looks as this isn't actually an OBD I, those are after 91? It does look like it has an O2 sensor, would that have any effect on the ignition if it only has the fender mounted module?

Gonna have to save up for a Chiltons for this for sure

 

Cool! I wonder if it also has the little sensor deep inside the distributor like was on the one in my old 79 Ford with the 400M? Had one of those go out once, the truck would run all day sitting in the drive way with the hood up, close the hood and drive off and it would die. Just that little change in heat would cause it to fail. Took forever to figure that one out.

 

Hahaha. Gotta love those problems.
I've heard certain Mitsubishi's would stall out if you slammed the hood. Something about sudden pressure change at the MAF sensor.

 

Would anyone know how well the BWD distributor cap from Advance Auto compares to the Napa Gold one?

Both have the brass terminals, just easier for me to get the Advance one if it is a good choice.

 

I wouldn't turn my back on a BWD.

 

Hey Jed. I have a mostly un-mollested 84 here. (the manual trans has a fifth gear, in case you have a tale wind). I'll guess the wiring and vacuum lines are the same, (sans what your auto trans might have). So if you have some specific issue regarding lines and wires, let me know, I can go take a peek.

Getten it through CA smog took some extra $$, then The head cracked. Dealt with that and Mom smoked the tranny. Dealt with that, then the rear end went. Dealt with that. I parked it when I got the 90 with the 4.0. Seems twice the power and about the same mileage. (back then, I'll just say 18).

Fun though! Motoring around in the snow and playen'! Loaded with 800 Lbs of tools, downshifting to 3'rd to try to stay "legal" at 45 MPH on grades on the highway was not all that much fun though.

 

Thanks guys!

Gotta say that #1 plug is a pain to get to. I got the bright idea that since my spark plug socket had a hex head on it I could put it on there and reach behind the A/C pump and get it loose, but there was no angle to make it work. Then I tried to remove the socket, forgot about the rubber gripper inside, no way to pull it off with just the tips of my fingers lol. Had to go to Lowe's and pick up a flexjoint to put on it and remove the plug, then got rid of the rubber gripper in the socket .

I feel like a rookie again, too many years with no time to play. Finally to a point I can again spend a little on toys like this.

 

Ha! Remotely in the same boat with my 84. I don't really have the energy for it, but I wouldn't mind having it ready to rock if my 90 w/over 270k has some serous issue. (I'm sure it will......). Running it now and then, since it's stored, I sort of melted the power steering pump.) Shimmed the throttle to 1800 or so then came in for a beer. Then noise and smoke. (I forgot to add PS fluid)(I use ATF)

Besides your spark...(I might not get too bent on that if it's sparking at all), (for now), are you familiar with the accelerator pump? In a "perfect world", with the choke and throttle plate open you should see a squirt as you depress the throttle. If that's not working, (probably isn't), it will almost certainly need a prime to fire. Always nice to have a towel you can weten, or an ABC fire extinguisher handy. After pouring a shot or so in there, (throttle open), then re-instaling the air cleaner cuts down on the chance a back-fire will cause an actual fire.

IIRC it's possible to remove the top of the carb without removing it. You can "sort of" get at some stuff, swab out the bowl, even change the accelerator pump gasket/ring. Not breaking the bowl gasket is tricky. I might gently tease it with my pocket knife. A can or two of Berrymans B-12 Kemtool might be handy. In the long run going that route may well be a headache. Pulling the carb, getting the kit, cleaning all of course would be better. Just to get her runnen though swabbing it out, getten the main jets flowen, might be a start....

I have 3 old cars here with rotted tanks that I run now and then. I just stick the fuel line into a gas can. (76 Wagoneer, 74 Jag, 78 Dodge camper/Van)

 

I used to pull apart Autolite two barrel carbs a lot when I had my 71 F100. Those things are dirt simple and I wish I could fit one on this thing lol. I will have to figure out this one but shouldn't be too difficult.

I picked up a compression tester on the way home today. I thought I would just pull #3 and make a quick check. Spun it over a few turns and got 135 or so, little low but not completely gone. I forgot to remove the coil wire and while it was spinning it tried to fire. I stuck the plug back in and and tried it again and the thing fired up! Ran about 6-8 seconds, sputtered and I touched the pedal and it died. Then when I tried again it turned over a few times, tried to hit once then the volts dropped and the starter started dragging. Gonna check all the grounds this weekend, if it doesn't rain too much, no garage and have to work on it in the driveway, gravel at that.