So I just got a 1990 Cherokee XJ. 220k and still runs like a champ, and I've put about 500 miles on it with no issues at all. Last night I was driving home (in the mountains of course) and it just started sputtering and died. Out of nowhere. Come to find out that it wont stay running with any electrical load on the system. it would start and run just fine and the minute i turn on my headlights or do anything it would just die. Not run rough or anything.

But what I think is the most odd thing is that we tried to see if a load right off the battery would change it so we touched wires from a buddy's hella light and the jeep still ran fine and the light lit up as it should. Ended up driving home using that one light straight off the battery. And even hitting the brakes the ABS and brake lights was enough to kill it sometimes.

And its all stock, other than a radio, but that shouldn't matter. This is the 'newest' vehicle I've ever had to mess with, I'm used to a carbed 71 GMC, with not a single sensor or smog equipment in sight.

So any Ideas on what it could be? I've looked all over on here and yet to find someone with a similar problem

Thank you so much to anyone who even looks on here

 

Start by cleaning ALL of the grounding points and not just the battery ground. Also have the alt and battery tested to make sure that they are operating correctly. A single bad ground on the XJ's can cause some very strange problems. Do those thing and see how that helps and if you are still having the same problem we can go from there.
BIW, Welcome to the forum.

 

After doing this, click on the pink link in my signature for tips on making your Renix Jeep reliable.

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

 

As the other two have said. GROUNDS GROUNDS GROUNDS.

 

thank you guys so much! I cleaned out all the grounds, and cleaned the IAC and it runs tip top again!
Also can an exhaust leak mess with the computer?

 

Sure can, if it is before the o2 sensor.

 

Glad to hear it.

No big deal on a Renix like yours because the O2 sensor is right in the manifold.